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I am from Brazil and I used to watch his videos even though I was there. Now I'm in Canada and the knowledge I got before coming here has already been very useful. 😊
As a Canadian I think I can confidently say the true answer is: "It depends". There are a lot of different types of snow and what works best for taction is going to depend on what kind of snow you're on, how deep it is, and what's under it.
As a snow wheeler, lower pressure will always get you further in the snow, in nearly all snow and ice conditions. It just ups the risk to the tire and you have to go slower.
@@MrMattc79 I think that's the recommendation for general use. low pressure might be great for traction, but it's a killer for fuel consumption. As mentioned here, it depends a lot on where you are driving and what kind of surface you're traveling on.
Excellent, as always. This does *not* mean that drivers should run their winter tires at low pressures all Winter; it merely means that temporarily-reduced pressures can help on a surface of snow; low pressures will reduce performance and tire life when driven on paved surfaces. Kudos to Pirelli for letting you run their tires outside recommended pressures.
Yeah - I know someone who does off-road stuff in the mountains who swears by 18 PSI (and likely not a randomly picked number given their profession) in the snow, which interestingly meshes closely with the results of this video, but they also use beadlocks and inflate/deflate coming on and off snow or other terrain as appropriate.
@@Rroff2 offroad tires are completely different than normal tires, even if yoiu run some AT tires then you probnably have some ridiculous sidewall profile like 75 or 80 or 85, with such numbers you can go low on pressure as the tyre will spread out evenly, if you tried it on low profile tire which is much stiffer you would probably lose it behind you after first accceleration
exactly my thinking, I will now about this trick of lowering to just under 2 bar in my case to improve traction on heavy snow surface if I hit it with my all seasons. They're set at 2.75 normally.
@@howabout2138 Almost forgot about that, almost every new car/minivan/suv has low profile tires (aka rim benders). I've driven my regular AT tires at about 15psi on sand and never worried about the bead coming off.
I am from Serbia. I was stuck on a big uphill. Snow about 30cm. After several attempts I deflate my pireli winter tires from 2.4 to 1.4 bar on my x5 Xdrive and it goes like a tank. You have the most useful videos on YT. Thanks
@JackAndTheBeanstalkr bars and kilopascals are on the same scale. It's just moving the decimal point, 1 bar = 100 kPa = 1000 hPa = 0.1 MPa ≈ 14.5 psi (note that all those values refers to the standard atmospheric pressure on earth)
The tire tread contact patch actually doesn't get much wider with lower tire pressures, but the contact patch does get a lot longer. Many off-road channels have demonstrated this with paint or chalk and lowering the tire down onto a surface to see the resulting contact area based on pressure. It can be quite a large percentage in added contact area. Of course, you don't want to drive at those pressures at higher speeds on the road, but if you're stuck in a snow rut, just like in sand, the lower pressure can be the difference of making it out or not. Once you're out you can reinflate the tires and be on your way
The lower the tyre pressure the longer the contact patch so you’re actually tending to become more of a tracked vehicle, and we all know how good those are in snow (Ref. snowmobiles).
Hello from Finland, that was really interesting test. Here we have ice and snow (normally) during winter, and we use studded tires, and friction tires, like in your video. What I've noticed, it's better to keep your tires inflated to the 2-2.5bar range, and there's a reason. Sometimes we might have a drop in temperature, like 20C from where it was, and tire pressure might come down fast too, and you don't want to drive long with underinflated tires, as they can fail horribly. Normal people don't check tire pressures daily, and older cars don't have tire pressure warning system in the car. And yes, we have a lot of older cars because of heavy taxing of cars, and high prices. If the tires gets old, like 5-6 years old, the rubber isn't any good because it hardens, and there's barely any grip. Now that's a lot of text, more than I normally do, but cheers, It was a great video. 😂
Absolutely correct. Not enough people, and even tire sales and maintenance shops, understand the relation between ambient temperature and pressure. It's the same in northern New England as you describe in Finland: through-out a winter season we can easily experience temperature variations from 60F (15C) in the shoulder seasons to -35F (-37C) on the cold mornings. Following the rule of thumb - 1PSI/10F in temperature change - the tire pressure would vary by close to 10 PSI over that temperature range. Throw in a pressure loss of approximately 1PSI/month through slow leakage, means that a semi-underinflated tire at the start of the winter season will be dangerously underinflated on a really cold morning in late January.
Here in Alaska when it gets below -50f like right now, you must drive for a quarter of a mile at about 25mph to get the tire to warm up and the flat spots from sitting all night to go away. Washboard city 😆 Also very common to have people with under inflated tires from the summer weather 70f to the coldest winter days -80f
I have absolutely no use for this information yet I still watched the video because I appreciate the effort that goes into these videos. Thanks for always bringing us such great content.
As a retired truck driver I say slow down in the winter. Take the few minutes to clean your windows and mirrors before hitting the road and give your car a quick look over to see if your lights and wipers and tires are safe for the drive. Also put the dang phone down and focus on the driving.
I live in Michigan’s Upper Peninsula with winters that last 5 months. Driving in deep snow, slush, in zero temps, and roads with tracks from accumulating snow! You are absolutely correct about “slowing down!” I have seen numerous 4x4 trucks passing people on highways losing control when changing lanes leaving the snow tracks in traffic lanes because the lead car is driving to slow for their convenience. Good tread, equal tire pressure, and being aware, all make safer driving. One tire being low in PSI can create issues in snow and ice.
@@jamesengland7461 slowing down improves traction. You don't need specific air pressure.. Look at the sticker in the Door jam of the driver door, slow down, pay attention. That's it. That's all.
Was really waiting for the important warning at the end. 1.38 bar /20 psi on hard surface or higher speeds might kill your tyres not just out of wear, but by damaging the sidewall from getting too hot from the increased deforming they have to do. Sure if you only deflate that far for a short, slow speed situation in the cold, it most likely won't. But as you said, there is real danger if that low pressure is kept. That said, most people have too low tyre pressure in cold weather anyways. Because they don't check regularly, and usually fill their tyres when the weather is nice and still somewhat warm. So when they put 2 bar in at +15°C and then it gets around freezing, they are already missing around 0.2-0.3 bar on average. (depending on the air volume in the tyre and when and under which circumstances they filled the tyre it can be more.)
Good point about people not checking the pressures. A finnish poll from 2019 says that most finns only check the pressures twice a year when they're changing from winter to summer tires and vice versa. You can imagine how low that pressure must drop between the changes...
I really should have reminded everyone to check pressures. AT least the Fins check their pressures twice a year, places like the UK where we don't change tires no one ever checks.
Well, my dealer managed to hand me over brand new car with tyres which were inflated to 1,5 bar / 2,5 bar left side vs right side. So I wouldn't expect any normal user to check the pressures unless there is an error message on the dashboard :-)
I bring the pressures down slightly. On average, I run 12.5% less, from 36 PSI to 31.5 PSI. The tires are Michelin Alpin P5, which are classified (USA) as performance winter tires. This video confirms my experience. Thank you for taking the time to run this test!
Roddy451@ .. Copy that. .. Here in Vail @ a snowy 8,200Ft elevation, daily snow-covered roads are a given. ... Never really pressure down the winter tires; simply pressure up on the money @ 36psi. . '23 E450 wagon and '20 Subi Outback XT Touring ... Michelin Alpin 5's all around. P.S., Took a flier on the neu CrossClimate 2 ...... this tire sucks BIG time in the snow and understeers like a dog on dry pavement; '20 Subi Outback XT (235/55/18). .. Returned the tires @ Costco and fitted the Subi with winter Alpin 5s. . Back to normal.
As someone that commonly runs 5 psi for snow-wheeling, I was really happy to see this test. I've contended for years that low pressures help in bottomless snow (that is show where you can't cut through to the pavement/dirt underneath). But I would have liked to see you mention that snow conditions very widely -- what works well one time may not the next. And, I still think higher pressures are better if you have conditions where the tires are digging all the way to the pavement/dirt. However, I've also said lower pressure doesn't help on ice. While your results are mixed, it looks like I might be wrong about this.
I wish I could test in deep snow, no one has really worked out how to do it fairly yet though, so we'll have to use the knowledge from people who do it in the real world like you :)
@@tyrereviews I would actually find testing in thin snow -- snow where the tires might have a chance to cut through to the pavement -- to be more interesting. The question to answer would be is it common to have conditions where a 50 psi tire will cut through and get better traction than a 20 psi tire that floats on a layer of snow? Unfortunately I think any kind of consistency between test runs would be very difficult to achieve.
@@andrewsnow7386 Exactly. I'd love to know all of this myself too but it has to be done properly and fairly, and sometimes that's just not possible (without throwing millions at it)
Agreed deep soft snow in a 4x4 is very similar to deep soft sand. Go as low as your tire wheel setup allows. Since 4x4s typically have a lot higher and stringer tire sidewall than typical car tires you are able to get to sub 10 psi with little risk of damaging the wheel/tire or popping the tire bead.
I’ve always heard that thinner winter tires are better because they can cut through the snow and grip better on ground then floating on top of it, which coincides with higher psi to reduce deformation. To test, you would need to find a consistent runway size track to allow many runs on fresh snow, then measure the maximum amount of force per square inch it can support before giving way to ground underneath. You could then tune the contact patch through tire pressure to spread the vehicle weight higher or lower than the threshold, and examine the tire tracks after to confirm the expected behavior.
As an ice racer for over 2 decades in loads of different cars and tires you might find it interesting that I settled on 15psi as the best all around pressure. With extended periods of excessive spinning/sliding pressure growth with a suprisingly hot tire by race end(like blued tread blocks kinda hot)would see hot pressures in the low to mid 20's. The grip was better at the start of the race and would fade a bit as the laps added up,but was too risky to start any lower.
Is that on a studded tire or studless? And what vehicle weights or factory pressure recommendation? I think I'll try lower pressures this year doing studless ice racing.
Street studded tire class but non studded classes are similiar. Like other motorsports the lighter the car the better,I put more effort then most and....a sawzall is your friend ;)
@@kevlarcorolla I'm currently dominating the field in weight at around 2300lbs curb weight with awd. I'm considering doing some basic aero to try to get some modicum of downforce, namely a flat floor and big spoiler/wing.
The problem is here in Canada a winter tire is in contact with the bare asphalt the vast majority of the time during the winter months because after it snows, it is plowed and then salted, which clears the snow and ice... at least on major roads and populated areas. That said, maybe this is more realistic for those who live in the country where dirt roads are more common.
After watching this I’ll be airing down to 20 psi for those blizzard commutes and back up again afterwards. I’m in Ottawa and it’s cold enough here that we get enough snowy roads. But yeah, growing up just outside Toronto, 99% of the time the roads were clear.
I agree. In northern-ish US, most major roads are free of snow and ice most of the time. Driving on fresh show is rare. Much more common is driving on packed snow/ ice left after the roads are plowed.
An underinflated tire has more grip on any surface. Not just ice. Of course, winter tires are useful only a few times per year. But when you need it 2-3% of extra grip can be a game changer.
Born and raised in Siberia, my driving experience has been over 25 years. I currently live in Canada, I have always driven winter tires with a pressure of 25 psi, I have never been stuck on both 4x4 and 4x2. Thanks for your video, now I'm sure that I'm doing everything right! Good luck!
Currently on a 2500 mile road trip on snow tires due to temps ranging from 65F to 15F and everything from sun to snow, and pressures have been on my mind, so this was super timely! I have tended to run them high when in hotter temps to reduce overall tire temps and avoid overheating the compound, and drop them when there's a chance of snow. Seems like more or less the right approach judging by your test. Thank you for such helpful videos!
Back in 88, I had an Accord LXI 2 door. I put better brakes, tires and struts on it. The tires were the star though. Yokohama AVS A+4. I did skid pad testing and tuned the tire pressures for maximum grip. Then I tried a slalom course. It felt sloppy, so I slightly raised the pressures until it felt good and re-tried the skid pad. The raised pressure cost me about 0.02g. If my memory serves, I used 31 in the front and 28 in the back. The tires wore evenly, and lasted longer than you would expect on my daily commute, and I had the advantage of having just about the quickest turning and stopping car on the road. Never did anything about the engine, so it was slow to accelerate, but I had many people in much more expensive cars discover that they could not hang with me in the tight twisty stuff. One guy in a 928 followed me for almost 10 miles to ask what I had done. I saw him a few months later running AVS Dry, and yea, he smoked me and then we started tuning his tire pressures.
As a Seasoned Canadian driver, i recommend manufacturers recommend psi on asphalt . In the backroads where the snow is packed down for months at a time we down pressure the tires. And traction off for fun. But driving on a frozen body of water is the best.
Thanks; looked like fun. Could have told you this living here in Northern Ontario. In the early 60's (yes, I'm a geezer)with my 58 Ford, we would lower pressure about 5 (or if confident 10) psi if there was a high chance of being stuck in snow. Carried a bicycle pump in the trunk to reinflate. Although surface contact area is fairly but not totally independent, there are a number of variables involve including: The temperature of the snow, the pressure on the snow (on ice, think of ice scates vs boots), the depth of snow, the rate of acceleration and the related, change in coefficient of static vs kinetic friction. Nowadays driving is sooo much easier with front wheel drive, stability control and much better snow tires.
I really enjoy your in depth videos! I’ve always said that the best compromise on winter tyres, is tall and narrow. That gives you a good penetration on slush, and a long footprint for traction. More nerdy stuff please😎😂 Happy winter from Norway.
Keep in mind a temperature drop of 10C can also loose 0.14 bar or 2 psi. So in winter it is important to check pressure in as cold a temperature as you can if you know temps will drop quite low on the trip. I've had the pressure warning come up many times when driving from like +5C to -15C and then back to +5C. Basically going over a mountain in Norway and when I get back down to sea level it might trigger. I usually add 0.1 bar in winter to account for temp drops. My garage rarely get below freezing so going out in -15C or below is a big difference.
I have driven for nearly 50 years and my experience with our vans at work has been to lower the driven wheels to 20psi on snow and reflate them as soon as off snow. This has worked in even recovering stuck drivers in our fleet and on just standard van tyres with no special pattern. Drive smoothly according to conditions and try to keep on fresh rather than compacted snow
I live in Louisiana in the USA. I've driven in sand, mud, and snow. It is normal for my wife and I to visit family in the wintertime in Northern states where snow, ice, and slush is normal. I have also driven heavy 18-wheelers (lorries for my European readers) and learned early on that reducing air pressure does help on snow. On my personal vehicles, reducing air pressure to about 20 psi definitely helps in snow because it widens the tire footprint. Moe
As a firefighter, the biggest thing is just slow down and make sure your windows are clean, of and put your winter tires on in advance, we had our first snowfall yesterday and our radios were dispatching non stop, our town alone had 5 car accidents within a few hours.
A lot of cars, especially small hatchbacks, state that the front tyres require more pressure than the rears, due to the weight of the engine. Going even all around can be in disagreement with your owners manual.
@@egocd Yeah my Qashqai even has 30 rear/33 front split and putting them to even noticeably impacts the steering and ride comfort. Unfortunately it isn't easy to get a good balance though as IMO 30 is too low on the rears and a lot of tyres don't seem to like it, while the steering starts to feel worse once the fronts rise above ~36 PSI and you need a good 3 PSI between the front and rear to maintain the normal levels of handling and comfort.
My experiment with Nokian tyres during a Canadian winter proved that the fastest way to destroy the tire casing is to run it below the placard pressure for the car. Car called for 32 psi, I went as low as 20 psi while experimenting. The traction was great. The weather warmed up, went back to the car's suggested pressure, a few warmer days later and 3 of 4 tire casings separated causing a severe vibration. When they were removed from the wheels there was no scuffing on the inside of the casing. 60% tread remaining tires went to the scrap pile.
@MikeYurbasovich i didn't say nokian were bad. I said it sounds like a QC problem with the particular set he had. Possibly he got old/new tires, pretty common with winter tires.
As a Jeep Wrangler driver that has 35s I can tell you we always air down offroad and it makes a huge difference. When I plan to drive on the snow I always air down as well and 20psi for both has always been a good starting point. I don't think the results would change much but 15psi is also usually the low end where going below that requires a certain need. Thanks for the awesome data!
Yeah but with 35s you are going for flotation. A big fat wide tire does flotation very well but if you want to cut down to the pavement then a big narrow tire does better. Of course pretty much any wet snow over a foot deep is probably going to need flotation.
@@monsaka7827 The only time you are cutting down to pavement is if its slushy and you can spray it out of the way. Any other snow on the road is just going to compress under the tire. If you could always just cut down, then there wouldnt be a whole lot of reason for snow tires.
@Jay-me7gw That is not what I meant at all. It's obvious to a brain dead chicken that tires running over snow are not going to contact pavement. But they will compress the snow. That compressed snow will resist shear under weight assuming your tires can grip it. Winter tires do an excellent job gripping it. Weight does a great job of increasing the shear strength.
315/75R16 on my H3, I go as low as 6-8PSI without beadlocks for deep snow (not offroad, but like, deep snow rescue/recovery neighborly stuff). Never lost a bead on 7.5" wide rims.
I live in Canada we have a solid mix of road. Highway. Snow, ice and slush covered roads. In my experience I always set my winter tire pressure at 30psi. Anything less can be dangerous when on cold Pavement but still provides great traction for all conditions
Winter tires go on tomorrow here in New Hampshire! These videos are fantastic, helped me pick the X-Ice Snow from Michelin for my Nissan Rogue Sport last year!
Had them on my 93 Mazda Protege lx. They were very good on ice. Deep snow wasn't their favorite thing. But the throttle pedal was good for keeping the car moving in the right direction. As long as the tires were spinning and the car moving forward I never got stuck or went off course. Never changed them or rotated them . Got five years out of them the fronts were done but the back tires were still 70 %. That car was easy on tires . Excellent tires in the cold and rain.
Thanks for validating what I felt last year - had an oil change and they over inflated my snow tires to over 40 psi and the SUV felt so different on the way home (snowy day). When I got home is when I figured it out and aired them back down to 33. With my conditions keeping them at 33 is the compromise for everyday driving.
I'm amazed that this is surprising to most. Coming from the off road and snow wheeling community, I've been dropping my tire pressure during snow storms to 20 psi for decades, it's unbelievable the difference. Actually here in the northeast they use to teach that trick in the drivers Ed books. I wish the "people of the internet" would do their own testing before they give horrible advice like running snow tire pressure at 50 psi for maximum traction, lol
@@tyrereviews no, I’ve never lost a bead either. 33x12.5r15 tires on 8” wide wheels. I think the 8” wheel pinched the bead of the wide tire very tight and maybe helped? To be fair I was almost exclusively doing
Nobody said to run 50 psi, the tester just did it to see the results. But, just like you have off road experience lots have heavy weight carrying and pulling experience with increased air pressures. The argument for more pressure was to pizza cut into the snow, not float over it with low air pressure. I guess, before snow tires got good, more air pressure was a solid technique.
I'd always been told higher pressure 'narrows' the tire, so it can dig in to the snow. Kinda like the same reasoning you don't want monster wide tires during winter or rain. I was told wrong and have learned.
I’m in New England. I run aggressive (triple snow peak) AT tires on my trucks at 35psi year round. Never had an issue with this setup. I’ve found you will gain more traction by adding a few hundred pounds to the bed/trunk than by adjusting tire pressure.
Well, that was interesting. People ask me quite frequently about it and I answer them with a stock "The manufacturer tests the tires quite a lot. What they recommend will be best MOST of the time. If you get stuck, then it is time to experiment.....". I run snow tires on my '85 Toyota P/U. I only put about 3,000 miles each year on it, so the longer lasting hard tread designs have to be replaced due to age long before they are even half worn. The snow tires have lasted three years now, and are only a 2/32nds down on tread, with 5/32's left to go before they have mandatory replacement at the end of the summer.... Mandatory meaning when I feel they are too worn. Minimum tread is ridiculous in shedding water...... Good vid, good testing ideas. Bravo.
Being a Swede, yes, lower preassure does work in snow as you explained but the it depends on the snow, wet snow and low pressure is like a boat. Now living in Scotland i rely purley on normal pressure, Michelin Crossclimate and snow socks, should i need it.
So when it comes to winter and carrying blankets, snow shovel etc you should also carry a means of re-inflating a tyre if you need to drop it down if you encounter enough snow to warrant dropping the pressure. Top tips as always. Thanks.
You should warn people on the dangers of running a tire severely underinflated for lengths of time, especially when your not always on snow/ice. It can lead to overheating even in cold condiotons and blowouts etc.
Now what we need is a way to adjust tire (tyre) pressure on the fly. It's being done in pro cycling (bicycle) racing now. Most places I go here in northern NY begin with a couple miles of country road where this could sometimes be useful, and then onto a highway where 20-25 psi wold be a deathwish. Thanks much for the testing. Very enlightening. Now who's going to tell rally racers who seem to prefer skinnier tires?
Loved the video and interesting takeaway! I knew for sure that lower pressure was better in sand (so many people get stuck in Saudi Arabia or Dubai, but get going once the pressure is lowered). So it’s interesting to see it’s the same for snow.
Yup, confirms my driving experiences. I run 25psi in my truck on road for winter. 20 performs better but I'm trying to consider tire wear, 32psi is recommended.
this is good but you really need to explain the anomaly at 30psi as it makes no sense. also you should do this again with 20, 25, 30, 35 and 40psi. these are more realistic and practical pressures that would give more useful information than unsafe pressures at 10 and 50psi for winter roads
FINALLY! I asked you if this test was coming four years ago. Which is best for snow tires, higher or lower pressure? I've been unable to get an answer from car magazine pages and Tire Rack here in the states because nobody knew the answer and nobody wanted to say anything but, "use the manufacturer's recommended tire pressures", which had to be bunk. One way had to be better or worse, right? I'll drop my snows, just put on yesterday, to 5psi below the recommended numbers. Can't do more than that, the tires will be eaten alive by snow-less roads and, a huge caution about lowering pressures before heading out on a cold and snowy day, Schrader valves can freeze open when the expansion or air comes out if there is any water inside the stem. You'll be left with a flat tire. Do pressure adjustments ahead of time or don't do it at all!
Great video! Thanks!! Here’s another data point for you: when I took my family on a tour of sand dunes in New England one summer, I learned that, to drive on the sand dunes, the driver said the tire pressure was set to 11! PSI. I never would have thought to go that low. And he was very specific about that because he checked it before we drove onto the sand!
The engineers do a pretty good job of making winters that grip better than standard (compounds and patterns), so fitting winters is most of the benefit. It'll probably stick to recommended pressures, as they've done all the engineering to come up with those, balancing snow/ice/slush and clear roads (unless you're in Scandewegia or the Alps, I'll bet many of us have mostly clear roads), wear and sidewall degradation etc etc. They seem to know what they're doing, and whilst there may be marginal gains from tweaking pressures, there will be down-sides too (its not all about acceleration and braking on snow and ice). Great and thorough testing regime, as always, and some intriguing results. I guess snow is a soft material, so the more tread/sipes in contact with the small crystals, the better performance in general - that's why winters have sipes after all.
I live in the colorado rockies. Vehicle spec with snow tires has always done me right. I've never even thought about playing with the pressures because it's never been an issue. Edit* but I appreciate you doing this experiment for us 😃👍
Here in the great white north of Canada, where lots of snow and -40C is common, I run my tires at least 10 lbs less than recommended manufacture settings. The confidence in braking and cornering is very positive. I run Michelin Aplin PA4's on a 2013 Mercedes AMG C63.
Really useful video. In Alaska 16 years ago there wasn’t any info on things like this. Arriving in September with only all season tires I was practically on skis after the first snow. Then, with studded snow tires, when the snow melts, there were too many walking speed near accidents on plate ice. The only info I could get was more pressure was better- to pizza cut through the snow. But, I’ve known that cornering and braking are more important than accelerating so, I’ll determine a figure based on your course times and braking figures. Knowing is half the battle. Thanks!
@@tyrereviews a wet test would be nice (skipping the 10psi), as many times during winter in snowy areas when temp is above 0C degrees there is a mix of "clean" main roads which are wet, and roads with snow&ice
@@tyrereviews what about aquaplaning with different pressures and testing in wet mud for slush as an orientation? Compacted snow should be possible though
Thank you very much for this video. This is important information for using the tires correctly. Since I have been using all-season tires, I drive with lower tire pressure in winter (approx. 0.4-0.5 bar). This means that the tire works harder and gets warmer. This is why the tire pressure increases more during the journey. In summer, the tire pressure is increased again by 0.4-0.5 bar.
Big thanks for this test. I think the discussions shouldnt be about riding with low pressure but to know that there is a chance to ride on when you get stuck! I was pleased that this is still the same with the new tires as we learned 45 years ago in switzerland. I like your great videos very much!
This is great to know...I always assumed higher pressure to press through the snow to get to solid surface better. 20 psi!! Who would've guessed?!?!? Great video!! Thanks.
10:25 if you've gotta know! Last winter, with temperatures close to -10°C, my dash showed very low tire pressures, so I inflated them back to the OEM recommendation of 2.6 bar for fuel efficiency or speeds > 160 km/h (front axle, Germany, winter oriented 4 season tire). Unfortunately, this was not ideal for the colder conditions; just 10 meters from home, on a compacted snow-covered uphill right turn, I started sliding backwards. Had to install my tire socks to complete the journey, so close yet so far. My observation has been that, applying the recommended pressure at 20°C ambient seems to cover all scenarios. Since that incident, I adjust the tire pressures by adding or subtracting 0.1 bar for every 5-degree deviation from 20°C. With this approach, the wear and grip has been perfect in every condition. Can't tell whether that applies to all tire-OEM-car combinations, though.
The biggest concern I'd have with low tire pressure is uneven wear of the tread, as TR pointed out. I've got wider meats for my summer tires and I'm getting excessive inside/outside shoulder wear despite inflating 3 to 4 PSI above normal tires on my car. Next summer, I'll be aiming for 6 PSI over stock.
Can you elaborate on the tire pressure at 20 degrees? Is it written in your manual that the tire pressure should be checked at 20 degrees? Does this mean that the winter tire will be severely underinflated at 0 degrees and colder?
I have always had day and night results with running lower tire pressure in bad conditions here in Canada. In a front weight biased car, like my 04 Impala, where 60% of the weight is up front and 40% is in the rear; dropping my pressures to 30/20 (normally 35/35) make almost 0 fish tailing and confident braking. It plows through snow on any given tire pressure, so no complaints there.
Im glad i read the comments first because this doesnt apply to me much at all. The problems i have are with ice, not snow. I wish they could just not plow at all, it would be great for those of us with proper tires
@@tyrereviews, thank you a lot! No rush, just being "worried" that it won't going ot make it for this season, and I'm really curious on it, as for the last 3 years switched to "Sumer+All season" instead of "Sumer + Winter"
You know, you'd be the perfect channel to explore the effects of car setups on lap time. Like how do stiffer shocks, springs, anti-rolls etc affect handling AND how they interplay with each other.
Without having watched the video yet, I assume it's the golden middle (or how it's expressed in proper English). Let me watch the video now to see if my wild guess is wrong or right 🤓
I have wheels at the tire hotel, they put in 2.8 front and 2.9 rear, on a 2009 Lexus IS 250! I said guys it's not an SUV 😅 dropped to 2.6 and 2.7. After seeing this, I'm going to try out 2.1 front and 2.2 rear.
Hello and thank you for all your time and effort that was an awesome video. I live in Pennsylvania and at times we can get a considerable amount of snow especially in the past. As far as your testing goes you have a lot more going on there than you spoke about. If you were to do the same testing in sand ( hello everyone in South and Central America ) you would be able to see the shape of the sand under the tire when you drive over it. The more pressure you have like 50 psi the tire will grow but also can cup outward across the tread like the tire is bulging. It may not be obvious when the car is sitting still but once the tire starts to spin it's a bit of a different story with centrifugal forces. A very exaggerated example of this will be the rear tires on a top fuel dragster which probably only have about 12 PSI in them. With that said higher pressure will be more suited for digging in which in snow or sand is really NOT what you want. Handling would also be decreased because you're kind of riding on a narrow very hard due to the air pressure somewhat bulging tire. As the pressure gets lower ( 40, 30, 20, 10psi ) you would be cupping the tire inward capturing the snow under the tire actually forcing the tire to ride on top of it. Not to mention with lower pressure like 10 psi the tire will be wider EXCEPT the sidewall will be softer which will give more causing the handling to deteriorate exponentially. Going straight is awesome going through corners not so much. Something else to consider unless you're on a snow covered road course most winter snow driving is NOT aggressive. If you want to get aggressive you better invest in a set of studded snow tires. Other than that winter driving is basically slow and steady going very easy in the turns to get to where you're going and get off the road. With that said you were saying you kept the car in first gear the whole time. In a way that's counterproductive because you would be applying. more torque to the front wheels which is going to cause them to spin easier. It will be better to shift sooner keep the RPMs down which will have less of a chance of spinning the tires. It's almost like you would be lugging the engine. That's all I can think of but what I would like to see is another test where you show the pattern in the snow tire makes at each tire pressure and that will explain a lot. The same goes for anyone in the warmer climates you could do the same thing in the soft dry sand, it will give similar results and you will be able to see the pattern clearly. In closing, when I lived in North Carolina upon entering Carolina Beach with a 4x4 there was a beach access sign that advised to lower the tire pressure to either 10 or 20 psi I can't remember. There was also a tire filling station to pump back up when you were leaving. And for the people who thought they knew something they didn't there was also a sign saying that if you got stuck on the beach and they had to pull you out you were paying dearly for it 😂
On packed snow yes, to a point. But winter roads arent always this prepaired, if There's loose snow ontop a wider tire will slide on top of the snow, and a narrower will cut through the loose snow to come in contact with the packed snow underneath, which is why rallycars use narrow tires in snow. They used 135 width tires a couple of years ago to cut through the snow into the ice at the bottom. A wider tire will also wander alot as packed snow is almost never level. There is a lot of ruts, and the wider tire will hook into them more than a narrower tire.
Driving since 1972 and father gave advice then that reducing TP to about 20psi would get me out of most problems. Used this advice both in UK but also Germany and Austria when I lived there and the advice has never let me down in tricky snow 👍🏻
In just a few years all car enthusiasts' doubts will be gone! You do cover it all! Another amazingly clear, relevant and well done test. I feel the results will be valid on specifically this type of tire (a high quality winter tire). Potentially studded tires will follow a different trend and also all terrain tires.
Great Test - I always wondered about the best pressure in winter... As for Ice Braking Test - I think the key factor behind better braking at 10 psi is simply Surface Area... Braking in a straight line ought to 'Mush' the tire directly into the ice, increasing the footprint or contact patch in proportion to the braking effort. More Surface Area, Same Normal Force Should result in More Friction... At least that would be my guess.
@@captindan5460 here in Germany you're usually given multiple tire pressures. Mostly it's empty normal driving, fully loaded and good Fuel economy. Some sporty cars throw in an extra value for high Performance driving.
Thanks for confirming my best guess. I've had positive experiences lowering the front tire pressures in FWD wagons by 0.2-0.4 bar in winter. Much more predictable behaviour with the balance moving toward oversteer. On a snowy commute, it's reassuring to know that understeer is not the default skid and that I have more ways to correct a skid. That is to say - lowering front tire pressure increased front tire grip
Absolutely fascinating, as always! Confirmed my bias toward lower pressures. Similarly, off road, particularly on rocks and sand, 10-15psi is commonly used, but only at very low speeds. Generally, the greater the contact patch, and tread deformability, the better the grip, though with loss of steering response, predictably. Amazing work! Looking forward to your next revelatory test!
@ always do, even though I never get to drive on snow these days… in Australia! By the way, I’m getting my new BFG KO3s next week, for my Ranger Raptor, 315/70x17, so I might take them to the snow, if there is any, next winter, while you’re testing UUHP summer tyres!
This is an awesome analysis. Thank you for doing this. Clearly, there is a trend that lower PSI does improve the braking, but the most interesting thing is that the amount of improvement is minuscule. The greatest gain is seen comparing with the higher 50 psi, where most car tires in the USA are not even rated for that level anyway. Additionally, under inflating the car tire will increase the risk of a flat, and you also lose a lot of gas mileage. Basically, the conclusion seems to be that keeping the tire at its rated value seems best even in the snow given the increase risk of tire damage or flat, and the markedly reduced gas mileage, despite a essentially minuscule amount of improvement in the braking distance.
I was really hoping stock pressures would win. The intended tire shape would be maintained and I could set and forget it. Great video as always. Good to know I could drop pressures temporarily if I was in a pinch.
Two fine points. On a radial tire, the tread contact patch does not get significantly wider as you lower pressure. It gets longer. The ground pressure of the tire does not change when the car is braking, as you stated. The ground pressure is related solely to tire pressure and a rule of thumb is that it is approximately equal to tire pressure..
Your results do not surprise me at all. Having driven in the desert before ever driving in snow, I have found the two conditions require pretty similar driving styles. In the desert, lowered pressures are the standard for good traction and control. Well done on your scientific method. The data speaks for itself.
I keep the pressure proportional to the load. Too low and too high are bad for traction. But in loose snow it is soft. For cross-country ability. Thank you.
Thank you for the great video and for listening to our comments. I emailed you about that topic one year ago, and here we are! Thank you! Finally, lower is better-that's confirmed. If the golf's base pressure is 32 PSI, lowering it to around 20 PSI will improve its traction and other criteria by around 10%. I don't believe driving with 10 PSI lower in snowy conditions damages tires or wheels.
You would want to go up and over the snow because digging in could get you high centered. Some big four-wheel drives don't care about high centered because they have the body height to deal with it, but for most of us mere mortals we want to go up and over the snow. So I would say having a wider tire with the best traction you can afford would be the way to go. I just bought Bridgestone Blizzaks and inflate them to whatever the sticker says on my door sill. Then I let them go lower in pressure if the temperature gets colder, for better traction on ice. So far so good. I'm happy with the Blizzaks. I can feel the difference between dedicated snow tires and all-seasons.
Funny how this is very much in line with my experience for adventure motorcycle tires, especially your braking test. That between 2.8 and 1.5bar is where most of grip improvement happens. I think this is area where most of tire deflection /contact patch increase happens. (Obviously not necessarily on snow but grip in general, especially offroad)
FANTASTIC VIDEO!!! Finally proof of what I have known from experience my whole life. The way to maximize this effect, is by running tire/wheel sizes that can more easily handle those lower pressures. Smaller rims, higher ratios, more load rating.... Been telling people this for years on forums and always run into resistance. I run as low as 6-8PSI on my SUV with huge tires and tiny rims (315/75R16), and as low as 15PSI in my sedan (215/60R16) for deep snow driving. These pressures provide the contact patch to make it home through just about anything. FEET of snow in the SUV is no problem. ~20PSI is perfectly safe for reduced speeds in cold weather in most cars too. Just don't go flying down the highway at 80MPH at 20PSI.
Afaik, you can look up any specific tire size parameter on a tire load table , and all the brands will all have the same load capacity at a given pressure. You can reduce pressure down to the matching load that is your *actual* weight and then drive that until the cows come home. Going below that pressure should work, but you're in the safety margin. Finding a tire size/spec that fits and can be pressure reduced while still having the actual weight capacity would be the trick, yep. With a full size suv you can typically go with P or LT tires. LT have higher weight capacity per given size, so they could be aired down more.. but I gave up on LT... I like a smoother ride.
@@davecarpenter4917 I think you may have missed the point I was making. This video was a follow-up to a video that compared different profile tires (narrow, wide, with different rim sizes). With changes to tire profiles, we change the load capacity of the tire for a given pressure, but that previous video failed to give the tires that had more capacity per pound of pressure the advantage of reduced operating pressures, so the conclusion of that video was wrong for those who would adjust pressures for the conditions they are driving in, and take advantage of more headroom on the bottom end of the range on higher series tires.
@@BlackForestWoodStoving I think we're on the same page. I was saying that tire sizes/profiles can be found that would still carry the same load, but at a lower pressure. Most people dont know about tire tables, they just install whatever the door pillar sticker says. Obviously there are physical space limitations, but often one can pick a range of tire if you dont mind minor errors in the speedo.
i think the reason of the accelerating & breaking different numbers is due to the hardness & softness of the front & the rear suspension. when accelerating the body weight gos to the rear, while breaking gos to the front
Thanks for this test! There is always something to learn from your videos. Thanks to the rigorous methods you use we get reliable information. This is way more than entertainment. I had one memorable experience in this topic. No clue why exactly but once I have overinflated my rear tyres by 0,5 bar (2,3 instead of 1,8). The car started to have noticable oversteer in the corners on snow even at modest driving speeds. Fun on a closed track but quite scary on public roads :D
I recall well being stayed in snow on wide summer tires on a high performance car, it just wouldn’t go! So I got out of the car, let enough air out to where I could easily see the sidewalls begin to fold, got back in the car and simply drove away! Miraculous 🤷♂️
Grew up in Midwest of the USA. Deep snow winters are par for the course. Get stuck, let some air out. More often then not, drive right out. Otherwise, time to chain up.
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some of the links just take you to amazon homepage
Awesome video as always! Thank you!
The Fanntik stuff really looks tempting but the promo codes appear to not be valid on the German Amazon.
Shame about the amazon promo but hopefully they'll have a good blackfriday deal anyway!
can you please do this in a ultra high performance summer tire on dry road
I'm from Brazil, I have never even seen a winter tire in my life, but i just like the way you spread good information in your videos.
I would like to visit Brazil one day
That's super kind, thanks for watching.
Съезди в Аргентину там должен быть снег
Go to a ski resort in Chile or Argentina and have fun.
I am from Brazil and I used to watch his videos even though I was there. Now I'm in Canada and the knowledge I got before coming here has already been very useful. 😊
As a Canadian I think I can confidently say the true answer is: "It depends".
There are a lot of different types of snow and what works best for taction is going to depend on what kind of snow you're on, how deep it is, and what's under it.
Indeed.
Speed is also a contributing factor. I'd avoid high speed on low pressure.
Agree entirely!
As a snow wheeler, lower pressure will always get you further in the snow, in nearly all snow and ice conditions. It just ups the risk to the tire and you have to go slower.
My tire distributor said 35 psi was the right tire pressure for my 285/45 R22 tires.
@@MrMattc79 I think that's the recommendation for general use. low pressure might be great for traction, but it's a killer for fuel consumption. As mentioned here, it depends a lot on where you are driving and what kind of surface you're traveling on.
Excellent, as always. This does *not* mean that drivers should run their winter tires at low pressures all Winter; it merely means that temporarily-reduced pressures can help on a surface of snow; low pressures will reduce performance and tire life when driven on paved surfaces. Kudos to Pirelli for letting you run their tires outside recommended pressures.
100%
Yeah - I know someone who does off-road stuff in the mountains who swears by 18 PSI (and likely not a randomly picked number given their profession) in the snow, which interestingly meshes closely with the results of this video, but they also use beadlocks and inflate/deflate coming on and off snow or other terrain as appropriate.
@@Rroff2 offroad tires are completely different than normal tires, even if yoiu run some AT tires then you probnably have some ridiculous sidewall profile like 75 or 80 or 85, with such numbers you can go low on pressure as the tyre will spread out evenly, if you tried it on low profile tire which is much stiffer you would probably lose it behind you after first accceleration
exactly my thinking, I will now about this trick of lowering to just under 2 bar in my case to improve traction on heavy snow surface if I hit it with my all seasons. They're set at 2.75 normally.
@@howabout2138 Almost forgot about that, almost every new car/minivan/suv has low profile tires (aka rim benders). I've driven my regular AT tires at about 15psi on sand and never worried about the bead coming off.
I am from Serbia. I was stuck on a big uphill. Snow about 30cm. After several attempts I deflate my pireli winter tires from 2.4 to 1.4 bar on my x5 Xdrive and it goes like a tank. You have the most useful videos on YT. Thanks
the rest of the world uses kPa
@JackAndTheBeanstalkr bars and kilopascals are on the same scale. It's just moving the decimal point, 1 bar = 100 kPa = 1000 hPa = 0.1 MPa ≈ 14.5 psi (note that all those values refers to the standard atmospheric pressure on earth)
Google it bro. Don't be lazy
The tire tread contact patch actually doesn't get much wider with lower tire pressures, but the contact patch does get a lot longer. Many off-road channels have demonstrated this with paint or chalk and lowering the tire down onto a surface to see the resulting contact area based on pressure. It can be quite a large percentage in added contact area. Of course, you don't want to drive at those pressures at higher speeds on the road, but if you're stuck in a snow rut, just like in sand, the lower pressure can be the difference of making it out or not. Once you're out you can reinflate the tires and be on your way
You are correct
Same reason they do it at the drag strip
Came here to say that thanks
The lower the tyre pressure the longer the contact patch so you’re actually tending to become more of a tracked vehicle, and we all know how good those are in snow (Ref. snowmobiles).
@@ianmathieson65 tyre=tire
Hello from Finland, that was really interesting test. Here we have ice and snow (normally) during winter, and we use studded tires, and friction tires, like in your video. What I've noticed, it's better to keep your tires inflated to the 2-2.5bar range, and there's a reason. Sometimes we might have a drop in temperature, like 20C from where it was, and tire pressure might come down fast too, and you don't want to drive long with underinflated tires, as they can fail horribly. Normal people don't check tire pressures daily, and older cars don't have tire pressure warning system in the car. And yes, we have a lot of older cars because of heavy taxing of cars, and high prices. If the tires gets old, like 5-6 years old, the rubber isn't any good because it hardens, and there's barely any grip. Now that's a lot of text, more than I normally do, but cheers, It was a great video. 😂
Absolutely correct. Not enough people, and even tire sales and maintenance shops, understand the relation between ambient temperature and pressure. It's the same in northern New England as you describe in Finland: through-out a winter season we can easily experience temperature variations from 60F (15C) in the shoulder seasons to -35F (-37C) on the cold mornings. Following the rule of thumb - 1PSI/10F in temperature change - the tire pressure would vary by close to 10 PSI over that temperature range. Throw in a pressure loss of approximately 1PSI/month through slow leakage, means that a semi-underinflated tire at the start of the winter season will be dangerously underinflated on a really cold morning in late January.
Here in Alaska when it gets below -50f like right now, you must drive for a quarter of a mile at about 25mph to get the tire to warm up and the flat spots from sitting all night to go away. Washboard city 😆
Also very common to have people with under inflated tires from the summer weather 70f to the coldest winter days -80f
Привет Я раньше жил в России и шипованные шины nokian hakapelita самые лучшие
@@moderndiogenes insane weather Alaska
@@vermontsownboy6957 PV=nRT...
I have absolutely no use for this information yet I still watched the video because I appreciate the effort that goes into these videos. Thanks for always bringing us such great content.
Glad you enjoyed it!
As a retired truck driver I say slow down in the winter. Take the few minutes to clean your windows and mirrors before hitting the road and give your car a quick look over to see if your lights and wipers and tires are safe for the drive. Also put the dang phone down and focus on the driving.
Of course, but this is not the subject of the video, which is if you can improve traction with air pressure.
I live in Michigan’s Upper Peninsula with winters that last 5 months. Driving in deep snow, slush, in zero temps, and roads with tracks from accumulating snow! You are absolutely correct about “slowing down!” I have seen numerous 4x4 trucks passing people on highways losing control when changing lanes leaving the snow tracks in traffic lanes because the lead car is driving to slow for their convenience. Good tread, equal tire pressure, and being aware, all make safer driving. One tire being low in PSI can create issues in snow and ice.
@@jamesengland7461 slowing down improves traction. You don't need specific air pressure.. Look at the sticker in the Door jam of the driver door, slow down, pay attention. That's it. That's all.
Amen
Best advice in these comments!!!
Was really waiting for the important warning at the end.
1.38 bar /20 psi on hard surface or higher speeds might kill your tyres not just out of wear, but by damaging the sidewall from getting too hot from the increased deforming they have to do. Sure if you only deflate that far for a short, slow speed situation in the cold, it most likely won't. But as you said, there is real danger if that low pressure is kept.
That said, most people have too low tyre pressure in cold weather anyways. Because they don't check regularly, and usually fill their tyres when the weather is nice and still somewhat warm.
So when they put 2 bar in at +15°C and then it gets around freezing, they are already missing around 0.2-0.3 bar on average. (depending on the air volume in the tyre and when and under which circumstances they filled the tyre it can be more.)
Good point about people not checking the pressures. A finnish poll from 2019 says that most finns only check the pressures twice a year when they're changing from winter to summer tires and vice versa. You can imagine how low that pressure must drop between the changes...
@@Pusahispidasaimensis OMG ... I test tyre's pressure each month 😂
I destroyed my PS4s-es tire walls with too low pressure
I really should have reminded everyone to check pressures. AT least the Fins check their pressures twice a year, places like the UK where we don't change tires no one ever checks.
Well, my dealer managed to hand me over brand new car with tyres which were inflated to 1,5 bar / 2,5 bar left side vs right side. So I wouldn't expect any normal user to check the pressures unless there is an error message on the dashboard :-)
I bring the pressures down slightly. On average, I run 12.5% less, from 36 PSI to 31.5 PSI. The tires are Michelin Alpin P5, which are classified (USA) as performance winter tires.
This video confirms my experience. Thank you for taking the time to run this test!
Glad you've found something that works for you
Roddy451@ .. Copy that. .. Here in Vail @ a snowy 8,200Ft elevation, daily snow-covered roads are a given. ... Never really pressure down the winter tires; simply pressure up on the money @ 36psi. . '23 E450 wagon and '20 Subi Outback XT Touring ... Michelin Alpin 5's all around.
P.S., Took a flier on the neu CrossClimate 2 ...... this tire sucks BIG time in the snow and understeers like a dog on dry pavement; '20 Subi Outback XT (235/55/18). .. Returned the tires @ Costco and fitted the Subi with winter Alpin 5s. . Back to normal.
Smart, I was going to say somewhere between 10-15% and you nailed it!
Agreed. I think more than 15-20% lower runs too many other risks of low pressure.
As someone that commonly runs 5 psi for snow-wheeling, I was really happy to see this test. I've contended for years that low pressures help in bottomless snow (that is show where you can't cut through to the pavement/dirt underneath). But I would have liked to see you mention that snow conditions very widely -- what works well one time may not the next. And, I still think higher pressures are better if you have conditions where the tires are digging all the way to the pavement/dirt. However, I've also said lower pressure doesn't help on ice. While your results are mixed, it looks like I might be wrong about this.
I wish I could test in deep snow, no one has really worked out how to do it fairly yet though, so we'll have to use the knowledge from people who do it in the real world like you :)
@@tyrereviews I would actually find testing in thin snow -- snow where the tires might have a chance to cut through to the pavement -- to be more interesting. The question to answer would be is it common to have conditions where a 50 psi tire will cut through and get better traction than a 20 psi tire that floats on a layer of snow? Unfortunately I think any kind of consistency between test runs would be very difficult to achieve.
@@andrewsnow7386 Exactly. I'd love to know all of this myself too but it has to be done properly and fairly, and sometimes that's just not possible (without throwing millions at it)
Agreed deep soft snow in a 4x4 is very similar to deep soft sand. Go as low as your tire wheel setup allows. Since 4x4s typically have a lot higher and stringer tire sidewall than typical car tires you are able to get to sub 10 psi with little risk of damaging the wheel/tire or popping the tire bead.
I’ve always heard that thinner winter tires are better because they can cut through the snow and grip better on ground then floating on top of it, which coincides with higher psi to reduce deformation.
To test, you would need to find a consistent runway size track to allow many runs on fresh snow, then measure the maximum amount of force per square inch it can support before giving way to ground underneath. You could then tune the contact patch through tire pressure to spread the vehicle weight higher or lower than the threshold, and examine the tire tracks after to confirm the expected behavior.
As an ice racer for over 2 decades in loads of different cars and tires you might find it interesting that I settled on 15psi as the best all around pressure.
With extended periods of excessive spinning/sliding pressure growth with a suprisingly hot tire by race end(like blued tread blocks kinda hot)would see hot pressures in the low to mid 20's.
The grip was better at the start of the race and would fade a bit as the laps added up,but was too risky to start any lower.
Is that on a studded tire or studless? And what vehicle weights or factory pressure recommendation? I think I'll try lower pressures this year doing studless ice racing.
Street studded tire class but non studded classes are similiar.
Like other motorsports the lighter the car the better,I put more effort then most and....a sawzall is your friend ;)
@@kevlarcorolla I'm currently dominating the field in weight at around 2300lbs curb weight with awd. I'm considering doing some basic aero to try to get some modicum of downforce, namely a flat floor and big spoiler/wing.
@@Levibetz
My mid engined awd R1 powered geo metro was right around 1700lbs and had 2 BIG wings with a combined area of approx 16 sq ft :)
The problem is here in Canada a winter tire is in contact with the bare asphalt the vast majority of the time during the winter months because after it snows, it is plowed and then salted, which clears the snow and ice... at least on major roads and populated areas. That said, maybe this is more realistic for those who live in the country where dirt roads are more common.
After watching this I’ll be airing down to 20 psi for those blizzard commutes and back up again afterwards. I’m in Ottawa and it’s cold enough here that we get enough snowy roads. But yeah, growing up just outside Toronto, 99% of the time the roads were clear.
I agree. In northern-ish US, most major roads are free of snow and ice most of the time. Driving on fresh show is rare. Much more common is driving on packed snow/ ice left after the roads are plowed.
Depends where in Canada you are.
An underinflated tire has more grip on any surface. Not just ice. Of course, winter tires are useful only a few times per year. But when you need it 2-3% of extra grip can be a game changer.
@@billyhw99 true, but that’s also true everywhere.
Born and raised in Siberia, my driving experience has been over 25 years. I currently live in Canada, I have always driven winter tires with a pressure of 25 psi, I have never been stuck on both 4x4 and 4x2. Thanks for your video, now I'm sure that I'm doing everything right! Good luck!
Currently on a 2500 mile road trip on snow tires due to temps ranging from 65F to 15F and everything from sun to snow, and pressures have been on my mind, so this was super timely! I have tended to run them high when in hotter temps to reduce overall tire temps and avoid overheating the compound, and drop them when there's a chance of snow. Seems like more or less the right approach judging by your test. Thank you for such helpful videos!
Back in 88, I had an Accord LXI 2 door. I put better brakes, tires and struts on it. The tires were the star though. Yokohama AVS A+4. I did skid pad testing and tuned the tire pressures for maximum grip. Then I tried a slalom course. It felt sloppy, so I slightly raised the pressures until it felt good and re-tried the skid pad. The raised pressure cost me about 0.02g. If my memory serves, I used 31 in the front and 28 in the back. The tires wore evenly, and lasted longer than you would expect on my daily commute, and I had the advantage of having just about the quickest turning and stopping car on the road. Never did anything about the engine, so it was slow to accelerate, but I had many people in much more expensive cars discover that they could not hang with me in the tight twisty stuff. One guy in a 928 followed me for almost 10 miles to ask what I had done. I saw him a few months later running AVS Dry, and yea, he smoked me and then we started tuning his tire pressures.
As a Seasoned Canadian driver, i recommend manufacturers recommend psi on asphalt . In the backroads where the snow is packed down for months at a time we down pressure the tires. And traction off for fun. But driving on a frozen body of water is the best.
Thanks; looked like fun. Could have told you this living here in Northern Ontario. In the early 60's (yes, I'm a geezer)with my 58 Ford, we would lower pressure about 5 (or if confident 10) psi if there was a high chance of being stuck in snow. Carried a bicycle pump in the trunk to reinflate. Although surface contact area is fairly but not totally independent, there are a number of variables involve including: The temperature of the snow, the pressure on the snow (on ice, think of ice scates vs boots), the depth of snow, the rate of acceleration and the related, change in coefficient of static vs kinetic friction. Nowadays driving is sooo much easier with front wheel drive, stability control and much better snow tires.
I really enjoy your in depth videos! I’ve always said that the best compromise on winter tyres, is tall and narrow. That gives you a good penetration on slush, and a long footprint for traction.
More nerdy stuff please😎😂
Happy winter from Norway.
Keep in mind a temperature drop of 10C can also loose 0.14 bar or 2 psi. So in winter it is important to check pressure in as cold a temperature as you can if you know temps will drop quite low on the trip.
I've had the pressure warning come up many times when driving from like +5C to -15C and then back to +5C. Basically going over a mountain in Norway and when I get back down to sea level it might trigger. I usually add 0.1 bar in winter to account for temp drops. My garage rarely get below freezing so going out in -15C or below is a big difference.
This confirms what the elders knew, it confirms what I was right to deflate the tires on the snow. Thank you very much for your excellent works
I have driven for nearly 50 years and my experience with our vans at work has been to lower the driven wheels to 20psi on snow and reflate them as soon as off snow. This has worked in even recovering stuck drivers in our fleet and on just standard van tyres with no special pattern. Drive smoothly according to conditions and try to keep on fresh rather than compacted snow
How did you re inflate them on the road? Portable tire pump?
@@Un1234l everyone has a portable pump - anyway - in case of punctures. My own one is cordless
I live in Louisiana in the USA. I've driven in sand, mud, and snow. It is normal for my wife and I to visit family in the wintertime in Northern states where snow, ice, and slush is normal. I have also driven heavy 18-wheelers (lorries for my European readers) and learned early on that reducing air pressure does help on snow.
On my personal vehicles, reducing air pressure to about 20 psi definitely helps in snow because it widens the tire footprint.
Moe
As a firefighter, the biggest thing is just slow down and make sure your windows are clean, of and put your winter tires on in advance, we had our first snowfall yesterday and our radios were dispatching non stop, our town alone had 5 car accidents within a few hours.
This test was the next step from the "wide vs narrow" in 2023. Thank you.
And in this test the difference looks noticable.
This for me also highlights how important it is for even tyre pressures all round. Great video as always!
Ha! The driver instructor from Birmingham. 😅
@@simsnqta Maybe not Birmingham, but importantly saving lives. Thankyou Ashley, Thankyou Tyre reviews
A lot of cars, especially small hatchbacks, state that the front tyres require more pressure than the rears, due to the weight of the engine. Going even all around can be in disagreement with your owners manual.
@@egocd Yeah my Qashqai even has 30 rear/33 front split and putting them to even noticeably impacts the steering and ride comfort.
Unfortunately it isn't easy to get a good balance though as IMO 30 is too low on the rears and a lot of tyres don't seem to like it, while the steering starts to feel worse once the fronts rise above ~36 PSI and you need a good 3 PSI between the front and rear to maintain the normal levels of handling and comfort.
Liverpool
My experiment with Nokian tyres during a Canadian winter proved that the fastest way to destroy the tire casing is to run it below the placard pressure for the car. Car called for 32 psi, I went as low as 20 psi while experimenting. The traction was great. The weather warmed up, went back to the car's suggested pressure, a few warmer days later and 3 of 4 tire casings separated causing a severe vibration. When they were removed from the wheels there was no scuffing on the inside of the casing. 60% tread remaining tires went to the scrap pile.
From a tire tech, 20 psi shouldn't destroy tires, thats poor QC not systematic issue
@@Jonathan-hx6oynokian tires are excellent winter tires. I prefer them over all others for Wisconsin winters
@MikeYurbasovich i didn't say nokian were bad. I said it sounds like a QC problem with the particular set he had. Possibly he got old/new tires, pretty common with winter tires.
@@Jonathan-hx6oy got ya
nice contradiction
As a Jeep Wrangler driver that has 35s I can tell you we always air down offroad and it makes a huge difference. When I plan to drive on the snow I always air down as well and 20psi for both has always been a good starting point. I don't think the results would change much but 15psi is also usually the low end where going below that requires a certain need. Thanks for the awesome data!
Yeah but with 35s you are going for flotation. A big fat wide tire does flotation very well but if you want to cut down to the pavement then a big narrow tire does better. Of course pretty much any wet snow over a foot deep is probably going to need flotation.
@@monsaka7827 The only time you are cutting down to pavement is if its slushy and you can spray it out of the way. Any other snow on the road is just going to compress under the tire. If you could always just cut down, then there wouldnt be a whole lot of reason for snow tires.
@Jay-me7gw That is not what I meant at all. It's obvious to a brain dead chicken that tires running over snow are not going to contact pavement. But they will compress the snow. That compressed snow will resist shear under weight assuming your tires can grip it. Winter tires do an excellent job gripping it. Weight does a great job of increasing the shear strength.
@ ok well you didn’t explain what you meant well. So maybe consult that brain dead chicken
315/75R16 on my H3, I go as low as 6-8PSI without beadlocks for deep snow (not offroad, but like, deep snow rescue/recovery neighborly stuff). Never lost a bead on 7.5" wide rims.
I live in Canada we have a solid mix of road. Highway. Snow, ice and slush covered roads. In my experience I always set my winter tire pressure at 30psi. Anything less can be dangerous when on cold
Pavement but still provides great traction for all conditions
Winter tires go on tomorrow here in New Hampshire! These videos are fantastic, helped me pick the X-Ice Snow from Michelin for my Nissan Rogue Sport last year!
Glad you like the Michelin, get a review on the site!
Had Michelin ice x for last car, and now my CX-5. Definitely an awsome tire for NH
@jbrown4137 They are unreal! Performance blew me away, blasting up to the mountains early before the plows came out to hit some fresh powder!
Good video, thanks for sharing! I've been using Bridgestone Blizzaks for the past 11 years as a winter tyre on my Toyata Prius. Brilliant tyre!
Had them on my 93 Mazda Protege lx. They were very good on ice. Deep snow wasn't their favorite thing. But the throttle pedal was good for keeping the car moving in the right direction. As long as the tires were spinning and the car moving forward I never got stuck or went off course. Never changed them or rotated them . Got five years out of them the fronts were done but the back tires were still 70 %. That car was easy on tires . Excellent tires in the cold and rain.
Thanks for validating what I felt last year - had an oil change and they over inflated my snow tires to over 40 psi and the SUV felt so different on the way home (snowy day). When I got home is when I figured it out and aired them back down to 33. With my conditions keeping them at 33 is the compromise for everyday driving.
I'm amazed that this is surprising to most. Coming from the off road and snow wheeling community, I've been dropping my tire pressure during snow storms to 20 psi for decades, it's unbelievable the difference. Actually here in the northeast they use to teach that trick in the drivers Ed books.
I wish the "people of the internet" would do their own testing before they give horrible advice like running snow tire pressure at 50 psi for maximum traction, lol
Same! I always will run lower in deep snow. 10psi when slow Offroad.
10psi you must be on beadlocks?!
@@tyrereviews no, I’ve never lost a bead either. 33x12.5r15 tires on 8” wide wheels.
I think the 8” wheel pinched the bead of the wide tire very tight and maybe helped? To be fair I was almost exclusively doing
Nobody said to run 50 psi, the tester just did it to see the results. But, just like you have off road experience lots have heavy weight carrying and pulling experience with increased air pressures. The argument for more pressure was to pizza cut into the snow, not float over it with low air pressure.
I guess, before snow tires got good, more air pressure was a solid technique.
I'd always been told higher pressure 'narrows' the tire, so it can dig in to the snow. Kinda like the same reasoning you don't want monster wide tires during winter or rain. I was told wrong and have learned.
Thanks
44 seconds in and I will say 25psi is the sweet spot... now on to the video!
I’m in New England. I run aggressive (triple snow peak) AT tires on my trucks at 35psi year round. Never had an issue with this setup. I’ve found you will gain more traction by adding a few hundred pounds to the bed/trunk than by adjusting tire pressure.
I've been waiting for this video :)
Good job!
Hope you enjoyed it!
Well, that was interesting. People ask me quite frequently about it and I answer them with a stock "The manufacturer tests the tires quite a lot. What they recommend will be best MOST of the time. If you get stuck, then it is time to experiment.....".
I run snow tires on my '85 Toyota P/U. I only put about 3,000 miles each year on it, so the longer lasting hard tread designs have to be replaced due to age long before they are even half worn. The snow tires have lasted three years now, and are only a 2/32nds down on tread, with 5/32's left to go before they have mandatory replacement at the end of the summer.... Mandatory meaning when I feel they are too worn. Minimum tread is ridiculous in shedding water......
Good vid, good testing ideas. Bravo.
Being a Swede, yes, lower preassure does work in snow as you explained but the it depends on the snow, wet snow and low pressure is like a boat. Now living in Scotland i rely purley on normal pressure, Michelin Crossclimate and snow socks, should i need it.
So when it comes to winter and carrying blankets, snow shovel etc you should also carry a means of re-inflating a tyre if you need to drop it down if you encounter enough snow to warrant dropping the pressure. Top tips as always. Thanks.
You should warn people on the dangers of running a tire severely underinflated for lengths of time, especially when your not always on snow/ice. It can lead to overheating even in cold condiotons and blowouts etc.
Now what we need is a way to adjust tire (tyre) pressure on the fly.
It's being done in pro cycling (bicycle) racing now.
Most places I go here in northern NY begin with a couple miles of country road where this could sometimes be useful, and then onto a highway where 20-25 psi wold be a deathwish.
Thanks much for the testing. Very enlightening. Now who's going to tell rally racers who seem to prefer skinnier tires?
Loved the video and interesting takeaway! I knew for sure that lower pressure was better in sand (so many people get stuck in Saudi Arabia or Dubai, but get going once the pressure is lowered). So it’s interesting to see it’s the same for snow.
Yup, confirms my driving experiences. I run 25psi in my truck on road for winter. 20 performs better but I'm trying to consider tire wear, 32psi is recommended.
this is good but you really need to explain the anomaly at 30psi as it makes no sense. also you should do this again with 20, 25, 30, 35 and 40psi. these are more realistic and practical pressures that would give more useful information than unsafe pressures at 10 and 50psi for winter roads
FINALLY! I asked you if this test was coming four years ago. Which is best for snow tires, higher or lower pressure? I've been unable to get an answer from car magazine pages and Tire Rack here in the states because nobody knew the answer and nobody wanted to say anything but, "use the manufacturer's recommended tire pressures", which had to be bunk. One way had to be better or worse, right? I'll drop my snows, just put on yesterday, to 5psi below the recommended numbers. Can't do more than that, the tires will be eaten alive by snow-less roads and, a huge caution about lowering pressures before heading out on a cold and snowy day, Schrader valves can freeze open when the expansion or air comes out if there is any water inside the stem. You'll be left with a flat tire. Do pressure adjustments ahead of time or don't do it at all!
Also, this only applies ins slow speeds on snow. don't drive on highway with under-inflated tires
Yes
Great video! Thanks!! Here’s another data point for you: when I took my family on a tour of sand dunes in New England one summer, I learned that, to drive on the sand dunes, the driver said the tire pressure was set to 11! PSI. I never would have thought to go that low. And he was very specific about that because he checked it before we drove onto the sand!
The engineers do a pretty good job of making winters that grip better than standard (compounds and patterns), so fitting winters is most of the benefit. It'll probably stick to recommended pressures, as they've done all the engineering to come up with those, balancing snow/ice/slush and clear roads (unless you're in Scandewegia or the Alps, I'll bet many of us have mostly clear roads), wear and sidewall degradation etc etc. They seem to know what they're doing, and whilst there may be marginal gains from tweaking pressures, there will be down-sides too (its not all about acceleration and braking on snow and ice). Great and thorough testing regime, as always, and some intriguing results. I guess snow is a soft material, so the more tread/sipes in contact with the small crystals, the better performance in general - that's why winters have sipes after all.
I live in the colorado rockies. Vehicle spec with snow tires has always done me right. I've never even thought about playing with the pressures because it's never been an issue.
Edit* but I appreciate you doing this experiment for us 😃👍
I’m Australian and we just love our UHP tyres all year round 😂
Here in the great white north of Canada, where lots of snow and -40C is common, I run my tires at least 10 lbs less than recommended manufacture settings. The confidence in braking and cornering is very positive. I run Michelin Aplin PA4's on a 2013 Mercedes AMG C63.
When you go offroad or for every day driving...?
Being from Sweden, I've known this for a long time!
Really useful video. In Alaska 16 years ago there wasn’t any info on things like this. Arriving in September with only all season tires I was practically on skis after the first snow. Then, with studded snow tires, when the snow melts, there were too many walking speed near accidents on plate ice.
The only info I could get was more pressure was better- to pizza cut through the snow.
But, I’ve known that cornering and braking are more important than accelerating so, I’ll determine a figure based on your course times and braking figures.
Knowing is half the battle. Thanks!
Interesting to see what would happen on compacted snow or slushy road conditions as these are more common for me as a European in southern Germany.
It would have been, it's just very hard to consistently test in slush. No one does it
@@tyrereviews a wet test would be nice (skipping the 10psi), as many times during winter in snowy areas when temp is above 0C degrees there is a mix of "clean" main roads which are wet, and roads with snow&ice
@@tyrereviews what about aquaplaning with different pressures and testing in wet mud for slush as an orientation? Compacted snow should be possible though
Thank you very much for this video. This is important information for using the tires correctly. Since I have been using all-season tires, I drive with lower tire pressure in winter (approx. 0.4-0.5 bar). This means that the tire works harder and gets warmer. This is why the tire pressure increases more during the journey. In summer, the tire pressure is increased again by 0.4-0.5 bar.
Amazing content as always. Can you make the same kind of tests about tyre pressures but in dry and wet? I'd love to see that
It's on the list!
Big thanks for this test. I think the discussions shouldnt be about riding with low pressure but to know that there is a chance to ride on when you get stuck! I was pleased that this is still the same with the new tires as we learned 45 years ago in switzerland. I like your great videos very much!
Oooh, that song at the end is a baaanger!!
Hahaha I just was saying this
So much of a banger that I had to find out what it was, which is "Wrath by AGST"
ruclips.net/video/d9GPAvKGlz0/видео.html
The next video on the channel will be full of them
This is great to know...I always assumed higher pressure to press through the snow to get to solid surface better. 20 psi!! Who would've guessed?!?!? Great video!! Thanks.
10:25 if you've gotta know! Last winter, with temperatures close to -10°C, my dash showed very low tire pressures, so I inflated them back to the OEM recommendation of 2.6 bar for fuel efficiency or speeds > 160 km/h (front axle, Germany, winter oriented 4 season tire). Unfortunately, this was not ideal for the colder conditions; just 10 meters from home, on a compacted snow-covered uphill right turn, I started sliding backwards. Had to install my tire socks to complete the journey, so close yet so far. My observation has been that, applying the recommended pressure at 20°C ambient seems to cover all scenarios. Since that incident, I adjust the tire pressures by adding or subtracting 0.1 bar for every 5-degree deviation from 20°C. With this approach, the wear and grip has been perfect in every condition. Can't tell whether that applies to all tire-OEM-car combinations, though.
The biggest concern I'd have with low tire pressure is uneven wear of the tread, as TR pointed out. I've got wider meats for my summer tires and I'm getting excessive inside/outside shoulder wear despite inflating 3 to 4 PSI above normal tires on my car. Next summer, I'll be aiming for 6 PSI over stock.
Can you elaborate on the tire pressure at 20 degrees? Is it written in your manual that the tire pressure should be checked at 20 degrees? Does this mean that the winter tire will be severely underinflated at 0 degrees and colder?
This is the best tire channel ever. Great work as usual
OEM PSI! Give or take a 1-5psi depending on the tire.
I have always had day and night results with running lower tire pressure in bad conditions here in Canada. In a front weight biased car, like my 04 Impala, where 60% of the weight is up front and 40% is in the rear; dropping my pressures to 30/20 (normally 35/35) make almost 0 fish tailing and confident braking. It plows through snow on any given tire pressure, so no complaints there.
Mostly I see the "air down" claims for offroad, not on street, even in winter. I stick with recommended (car door) pressure for my winter tires.
going 0.3bar lower than spec not only gives u grip, also saves your suspension, all new car pressures are made for fuel efficiency crap not longevity
@@shutu6338 Fair point. There is also tire wear to consider. Maybe I should start doing a Chalk test for optimal pressure for tire wear.
Im glad i read the comments first because this doesnt apply to me much at all. The problems i have are with ice, not snow. I wish they could just not plow at all, it would be great for those of us with proper tires
Thank you for yet another great test!
But what is happening with "All Season and Winter tyres" comparison review?
It's still on the list. It'll be a december video now sadly, just not enough hours in the day
@@tyrereviews, thank you a lot!
No rush, just being "worried" that it won't going ot make it for this season, and I'm really curious on it, as for the last 3 years switched to "Sumer+All season" instead of "Sumer + Winter"
You know, you'd be the perfect channel to explore the effects of car setups on lap time. Like how do stiffer shocks, springs, anti-rolls etc affect handling AND how they interplay with each other.
Without having watched the video yet, I assume it's the golden middle (or how it's expressed in proper English). Let me watch the video now to see if my wild guess is wrong or right 🤓
I use just 12 psi in my 2019 Honda monkey 125 at winter conditions.
Good grip.
No studs.
Greetings from Finland again 🎉
In the winter just stay around 2.0 BAR
I have wheels at the tire hotel, they put in 2.8 front and 2.9 rear, on a 2009 Lexus IS 250! I said guys it's not an SUV 😅 dropped to 2.6 and 2.7. After seeing this, I'm going to try out 2.1 front and 2.2 rear.
Hello and thank you for all your time and effort that was an awesome video. I live in Pennsylvania and at times we can get a considerable amount of snow especially in the past. As far as your testing goes you have a lot more going on there than you spoke about.
If you were to do the same testing in sand ( hello everyone in South and Central America ) you would be able to see the shape of the sand under the tire when you drive over it.
The more pressure you have like 50 psi the tire will grow but also can cup outward across the tread like the tire is bulging. It may not be obvious when the car is sitting still but once the tire starts to spin it's a bit of a different story with centrifugal forces. A very exaggerated example of this will be the rear tires on a top fuel dragster which probably only have about 12 PSI in them. With that said higher pressure will be more suited for digging in which in snow or sand is really NOT what you want. Handling would also be decreased because you're kind of riding on a narrow very hard due to the air pressure somewhat bulging tire.
As the pressure gets lower ( 40, 30, 20, 10psi ) you would be cupping the tire inward capturing the snow under the tire actually forcing the tire to ride on top of it. Not to mention with lower pressure like 10 psi the tire will be wider EXCEPT the sidewall will be softer which will give more causing the handling to deteriorate exponentially. Going straight is awesome going through corners not so much.
Something else to consider unless you're on a snow covered road course most winter snow driving is NOT aggressive. If you want to get aggressive you better invest in a set of studded snow tires. Other than that winter driving is basically slow and steady going very easy in the turns to get to where you're going and get off the road.
With that said you were saying you kept the car in first gear the whole time. In a way that's counterproductive because you would be applying. more torque to the front wheels which is going to cause them to spin easier. It will be better to shift sooner keep the RPMs down which will have less of a chance of spinning the tires. It's almost like you would be lugging the engine.
That's all I can think of but what I would like to see is another test where you show the pattern in the snow tire makes at each tire pressure and that will explain a lot.
The same goes for anyone in the warmer climates you could do the same thing in the soft dry sand, it will give similar results and you will be able to see the pattern clearly.
In closing, when I lived in North Carolina upon entering Carolina Beach with a 4x4 there was a beach access sign that advised to lower the tire pressure to either 10 or 20 psi I can't remember. There was also a tire filling station to pump back up when you were leaving.
And for the people who thought they knew something they didn't there was also a sign saying that if you got stuck on the beach and they had to pull you out you were paying dearly for it 😂
So wider tire is better, for sure
Yeah, can we get this tested...same tire just in varying widths. Everyone says go narrower, but I'm not sure I buy that.
@@SomeGuysGarage Tyre Reviews tested that as well. And it was pretty much a wash...
@@SomeGuysGarage I drive 235 all 4 and 285 all 4 on A7, sottozero 3, much much better on 285..
On packed snow yes, to a point. But winter roads arent always this prepaired, if There's loose snow ontop a wider tire will slide on top of the snow, and a narrower will cut through the loose snow to come in contact with the packed snow underneath, which is why rallycars use narrow tires in snow.
They used 135 width tires a couple of years ago to cut through the snow into the ice at the bottom.
A wider tire will also wander alot as packed snow is almost never level. There is a lot of ruts, and the wider tire will hook into them more than a narrower tire.
@@SomeGuysGarageHe's already done that, but of course thats on a packed prepaired snow course. Not the same as a road.
Driving since 1972 and father gave advice then that reducing TP to about 20psi would get me out of most problems. Used this advice both in UK but also Germany and Austria when I lived there and the advice has never let me down in tricky snow 👍🏻
That's it. I'm dropping my pressure from F/R 2.6/2.7 to 2.1/2.2 bar 🕺🏼
Just keep an eye on wear. Closely.
That's going to make your wear and fuel economy a lot worse.
@@swecreations at -20 to -25C? The rubber is pretty stiff at those temperatures.
In just a few years all car enthusiasts' doubts will be gone! You do cover it all!
Another amazingly clear, relevant and well done test. I feel the results will be valid on specifically this type of tire (a high quality winter tire). Potentially studded tires will follow a different trend and also all terrain tires.
there's a rule of thumb: "if running deflated tires , never travel more than 2x the PSI in MPH" -- so, at 10psi, don't go any faster than 20mph
So if I deflate my tires a few PSI to 30 PSI, then I shouldn’t drive faster than 60 mph? I feel like you just made that up.
Great Test - I always wondered about the best pressure in winter...
As for Ice Braking Test - I think the key factor behind better braking at 10 psi is simply Surface Area... Braking in a straight line ought to 'Mush' the tire directly into the ice, increasing the footprint or contact patch in proportion to the braking effort. More Surface Area, Same Normal Force Should result in More Friction...
At least that would be my guess.
BEST tire pressure, is the manufacturer recommended tire pressure.
Incorrect that tire pressure is for the best mpg, not necessarily grip and performance.
@@captindan5460 here in Germany you're usually given multiple tire pressures. Mostly it's empty normal driving, fully loaded and good Fuel economy. Some sporty cars throw in an extra value for high Performance driving.
The manufacturer recommended pressure is a great starting point
Washington state reporting- we typically on bad snow and ice days will run tire pressure at 25psi. Thank you for validating this.
From my experience, I would say this applies to sand as well. Good work man.
Thanks for confirming my best guess. I've had positive experiences lowering the front tire pressures in FWD wagons by 0.2-0.4 bar in winter. Much more predictable behaviour with the balance moving toward oversteer. On a snowy commute, it's reassuring to know that understeer is not the default skid and that I have more ways to correct a skid. That is to say - lowering front tire pressure increased front tire grip
Ofcourse there is also a fuel factor, load weight etc.. if someone cares :)
Nice test!
Absolutely fascinating, as always! Confirmed my bias toward lower pressures.
Similarly, off road, particularly on rocks and sand, 10-15psi is commonly used, but only at very low speeds.
Generally, the greater the contact patch, and tread deformability, the better the grip, though with loss of steering response, predictably.
Amazing work! Looking forward to your next revelatory test!
Glad you enjoyed it!
@ always do, even though I never get to drive on snow these days… in Australia! By the way, I’m getting my new BFG KO3s next week, for my Ranger Raptor, 315/70x17, so I might take them to the snow, if there is any, next winter, while you’re testing UUHP summer tyres!
This is an awesome analysis. Thank you for doing this. Clearly, there is a trend that lower PSI does improve the braking, but the most interesting thing is that the amount of improvement is minuscule. The greatest gain is seen comparing with the higher 50 psi, where most car tires in the USA are not even rated for that level anyway. Additionally, under inflating the car tire will increase the risk of a flat, and you also lose a lot of gas mileage. Basically, the conclusion seems to be that keeping the tire at its rated value seems best even in the snow given the increase risk of tire damage or flat, and the markedly reduced gas mileage, despite a essentially minuscule amount of improvement in the braking distance.
I was really hoping stock pressures would win. The intended tire shape would be maintained and I could set and forget it. Great video as always. Good to know I could drop pressures temporarily if I was in a pinch.
Two fine points. On a radial tire, the tread contact patch does not get significantly wider as you lower pressure. It gets longer.
The ground pressure of the tire does not change when the car is braking, as you stated. The ground pressure is related solely to tire pressure and a rule of thumb is that it is approximately equal to tire pressure..
Backpack kislux - also works for Compare - I can't find any difference and still use it for the gym
Your results do not surprise me at all. Having driven in the desert before ever driving in snow, I have found the two conditions require pretty similar driving styles. In the desert, lowered pressures are the standard for good traction and control.
Well done on your scientific method. The data speaks for itself.
I keep the pressure proportional to the load. Too low and too high are bad for traction. But in loose snow it is soft. For cross-country ability. Thank you.
Thank you for the great video and for listening to our comments. I emailed you about that topic one year ago, and here we are! Thank you!
Finally, lower is better-that's confirmed. If the golf's base pressure is 32 PSI, lowering it to around 20 PSI will improve its traction and other criteria by around 10%. I don't believe driving with 10 PSI lower in snowy conditions damages tires or wheels.
You would want to go up and over the snow because digging in could get you high centered. Some big four-wheel drives don't care about high centered because they have the body height to deal with it, but for most of us mere mortals we want to go up and over the snow. So I would say having a wider tire with the best traction you can afford would be the way to go. I just bought Bridgestone Blizzaks and inflate them to whatever the sticker says on my door sill. Then I let them go lower in pressure if the temperature gets colder, for better traction on ice. So far so good. I'm happy with the Blizzaks. I can feel the difference between dedicated snow tires and all-seasons.
Funny how this is very much in line with my experience for adventure motorcycle tires, especially your braking test.
That between 2.8 and 1.5bar is where most of grip improvement happens.
I think this is area where most of tire deflection /contact patch increase happens.
(Obviously not necessarily on snow but grip in general, especially offroad)
This channel is the best on this topic, thank you
FANTASTIC VIDEO!!! Finally proof of what I have known from experience my whole life.
The way to maximize this effect, is by running tire/wheel sizes that can more easily handle those lower pressures. Smaller rims, higher ratios, more load rating.... Been telling people this for years on forums and always run into resistance.
I run as low as 6-8PSI on my SUV with huge tires and tiny rims (315/75R16), and as low as 15PSI in my sedan (215/60R16) for deep snow driving. These pressures provide the contact patch to make it home through just about anything. FEET of snow in the SUV is no problem.
~20PSI is perfectly safe for reduced speeds in cold weather in most cars too. Just don't go flying down the highway at 80MPH at 20PSI.
Afaik, you can look up any specific tire size parameter on a tire load table , and all the brands will all have the same load capacity at a given pressure.
You can reduce pressure down to the matching load that is your *actual* weight and then drive that until the cows come home. Going below that pressure should work, but you're in the safety margin. Finding a tire size/spec that fits and can be pressure reduced while still having the actual weight capacity would be the trick, yep.
With a full size suv you can typically go with P or LT tires. LT have higher weight capacity per given size, so they could be aired down more.. but I gave up on LT... I like a smoother ride.
@@davecarpenter4917 I think you may have missed the point I was making. This video was a follow-up to a video that compared different profile tires (narrow, wide, with different rim sizes).
With changes to tire profiles, we change the load capacity of the tire for a given pressure, but that previous video failed to give the tires that had more capacity per pound of pressure the advantage of reduced operating pressures, so the conclusion of that video was wrong for those who would adjust pressures for the conditions they are driving in, and take advantage of more headroom on the bottom end of the range on higher series tires.
@@BlackForestWoodStoving I think we're on the same page. I was saying that tire sizes/profiles can be found that would still carry the same load, but at a lower pressure. Most people dont know about tire tables, they just install whatever the door pillar sticker says. Obviously there are physical space limitations, but often one can pick a range of tire if you dont mind minor errors in the speedo.
i think the reason of the accelerating & breaking different numbers is due to the hardness & softness of the front & the rear suspension. when accelerating the body weight gos to the rear, while breaking gos to the front
Thanks for this test! There is always something to learn from your videos. Thanks to the rigorous methods you use we get reliable information. This is way more than entertainment.
I had one memorable experience in this topic. No clue why exactly but once I have overinflated my rear tyres by 0,5 bar (2,3 instead of 1,8). The car started to have noticable oversteer in the corners on snow even at modest driving speeds. Fun on a closed track but quite scary on public roads :D
Excellent video, as allways ! Maybe worth mentioning that the recommended tire pressure of the Golf is 38 psi (2,6 bar).
I recall well being stayed in snow on wide summer tires on a high performance car, it just wouldn’t go! So I got out of the car, let enough air out to where I could easily see the sidewalls begin to fold, got back in the car and simply drove away! Miraculous 🤷♂️
Grew up in Midwest of the USA. Deep snow winters are par for the course. Get stuck, let some air out. More often then not, drive right out. Otherwise, time to chain up.