Brilliantly said, Andrew. You hit all the points I have used in explaining why I run a 235/85/16 on my Toyota Tacoma; save for the difference in our accent. My prior tire size was 285/75/16. I noticed a lot of difference in performance when I made the switch. I have driven in 3.5 feet of fresh, powdery, virgin snow, aired down to 8psi. I have gotten four other Toyota drivers to switch to narrower tires and they all appreciate my encouragement. Keep up the informative and entertaining videos.
I know your comment is more than 3 years old, but I run the same size tire on my '06 Sequoia. Performs well, and has slightly less rolling resistance on the road than the stock size. Gives me a whopping 0.5" inch of lift, too.
Here,here Andrew , I am a Canadian and have driven Jeeps for the past 40 plus years . Narrow Tires are the only way to go in our winter conditions and on our logging roads and trails during all seasons.
Snow driver here. I'd say you're pretty much right on with snow. The only time I or anyone I know would care about flotation is if the snow gets much deeper than the axles. If you're building a glacial expedition-specific vehicle, sure, but it'll suffer in almost all other imaginable driving conditions. (BTW they're often 6x6's for an even larger footprint too.) As with most things, it is compromise. There is no single go-anywhere best in all conditions/environments tire.
This just might be the the most intelligent and accurate discussion on tire size and pressure on RUclips with regards to 4WD, and more. I look at the ‘thumbs down’, there are a lot of ignorant and brain washed folks out there thinking wider is “always” better with traction. Americans as a rule, and I am one of them, think bigger is better and this surely is pervasive in the 4WD arena. Your points concerning the critical aspects of PSI per square inch is so misunderstood and in most cases ‘not’ understood, is exactly why so many people don’t understand, get or have real world side-by-side experience with this concept. Maximizing PSI down force, 99% of the time, is the most important variable to manage. It is a balance of course but far to often we go too wide and loose that magic balance with PSI downforce. Besides a 4 wheeler I am a farmer. So, I have heavy duty trucks (besides my beloved Jeep), aka one ton pickups.. Some are single rear wheeled and some are dualies . I live in Michigan; sand, mud and snow...traction is always an issue. No one drives their duallies unloaded in any of these conditions unless you remove one of the rear dual wheels because they just flat out get no traction. Not enough downward PSI spread across all that rear rubber. Removing one wheel or driving the same truck but not a dually is not a traction issue. Same physics and principles apply to traction in 4 wheeling, as a rule.
Swapped out my 285/75 16" KO2's a couple of days ago and went with the 255/85 16" 'skinny' KM3's .. I did a bit of research on these tires and was a bit worried that they would be loud .. not the case .. no louder then the KO2's. I was told that the one downside is that they don't handle as well on ice! I live in Tucson,AZ .. don't think I'll have to test that. Your testing and presentation on the 'skinny' sold me .. so thanks!
Hey I live in Tucson Arizona also I drive a disco 2 with grey bed liner body finish and a black roof. Anyway I run 285 75 16 and I swear if I'm down in the Rillito wash when it's super dry in the summer I can roll through any of the thick sand where no one has driven and come to a stop and take off just fine when skinnier tires seem to sink in forget the rolling resistance if you have the power and really my disco doesn't have a bunch. So just curious how do you feel about that now three years after this post when you ran Skinny's?
I've been thinking this direction for quite a while but never heard it explained this well backed with this much knowledge. One of the most informational videos I've ever watched thank you.
Started researching this more after your other video on choosing a skinnier tyre. Has absolutely blown my mind, and completely changed my understanding of offroad tyres. I've been preaching this to all my 4x4 mates since. Safe to say I'm ordering some skinnies for my car in preparation for a big trip in a few months. Great video and explanation!
Excellent video, thank you. 15:45 Our tractor, tall five foot 1.5 meters tires, narrow tires, to increase its grip, we lifted the axel to where both rear tires were just off the ground. Turned the rear tires so the air stem is at 12 o'clock then removed the air stem insert. Although all air escapes the robust sidewalls held the tire on the rim. With an adaptor connected to a water hose to the tire air stem filled both tires until the water overflowed the stem; returned the stem insert. Notice, there is now an air gap at the tire top. Connecting the air hose, we pressured each tire to 15 lbs. or 1.03 bars. Even after using the subsoil plow and turning plow, producing very soft fluffy soil for planting, the tires weight and narrow width provided tremendous grip to the ground. Water did not leak, we always maintained the correct air pressure; to check the tire pressure turn stem to 12 o'clock. The front tires did not contain water, much smaller diameter eighteen inches or so, and very narrow tires maybe four inches, 100 mm, pressured to 30 PSI, 2.06 Bars. As you stated, turning the wheel the tractor went where it was pointed, and the tractor was firmly planted on the ground, narrow tires all around.
I drive a semi truck, long haul here in the US. I didn’t have to watch past 1:15 rolling resistance and traction are the only things that matter to me as well. As a matter of fact rolling resistance is more important than even tire life. Reason being you spend so much less in fuel, if you get the right tire that it overcomes the lower tire life if that is even what anyone might contend. Got my sub love your content.
Excellent video! As always, thanks for sharing your wisdom. Also, submitting "Squinch" to Marriam-Webster as the new standard for any usage of square inch.
Another comment about tractor tires, a major reason tractor tires are wide is the fact you need huge area of tire to reduce pounds/sq. in preventing compaction of the soil in the fields. Dense soils are less suitable for crop growth.
This video help me decide to get a taller but thinner tire. From my 265/70R17 (10.4“ wide, 31“ tall) tire I’ll go for a 255/80/R17 (10” wide, 33” tall) tire. Looking forward to seeing the difference in performance.
Hi Andrew. Not sure if I agree wholeheartedly but as usual I'm super grateful for your experience-based opinions on all things overland! Well done and thanks for sharing.
The underlying equations are a bit complicated for a spreadsheet but can be coded up in any competent programming language. Refer to my comment above and the video. This aims to address the points you have raised.
Rolling resistance is smallest when the tire deformation is smallest (less deformation means less energy goes into heat). Smallest deformation will have a contact patch with the form of a circle, i.e. flotation tires (one that ends with LT) as their contact patch has a ameboid form. For non flotation tires the closest to circle will be square surface patch. If we take sand for example to have a good flotation one need to run about 0,7 bar. If the truck has weight of 750kg per tire that means a contact patch of 750/0,7=1071 sq.sm. If we take square root makes 32,7sm, or 12,88’ wide tire. Making a reality check by looking at competition tracks about 2,7 tons run 37x12,5 inch tires so theory is confirmed by practice.For flotation tire to have circle contact patch you need 14,5 inch wide, as area of circle is 3.14 times r times r. Good Luck.
It was the same story when I was in a mountain biking club, the cyclocross bikes with very narrow tyres were way better on the mud. Still, I got 305/70/16 for my overlander despite knowing they're "too wide", why? I just love the look of them, its that simple.
I run 255 85 16 on my troopy. Something you didnt touch on is that with narrow tires in deep sand ruts the side of your tyres dont rub on the ruts and you dont lose revs or momentum.
Thanks for the update Andrew. I'm fairly new to the overall 4wd/overland scene (been hovering around the edges for years but only dabbling) and your videos have been a big help. I would be curious to hear your thoughts/comments at some point on setting up a vehicle that also needs to regularly commute (I don't recall a video on this - if you have done, forgive my ignorance) as I'm at the point now of having to either 1. Keep the old clunker 4wd that has had a hard life + passenger car or 2. Convert into one (likely Prado or similar size). Your comments on how far tyres have come just twigged this in my head as I've always wondered what people run on their daily driver 4wd. Surely something like that KM3 is better than MT of the past but it must still substantially impact fuel economy/road manners? Is the better option two vehicles each for their specified purpose or is a single vehicle viable by using two wheel sets and removable equipment (draws/tanks/containers etc.) the better course (my worry with which is both weekend damage + the work involved to kit it back up every time you want to go somewhere)? Is a definitive answer even possible? As I said - just curious on your opinion.
Interesting talk, thank you. Weight also has to be taken into consideration, as well as rolling resistance when using wides, I.e., putting the drive components under more stress when accelerating or when tyres are spinning, especially when using steel wheels. I use 235 85 16s. I think a lot of folk use wide tyres for looks, which I agree, certainty do make the vehicle look the part and that's fair enough.
I can only comment on my experience over 30 years driving mainly in the UK and Australia many other countries but the main two I have done heaps of bush / trail driving and found 285/70/16 to be the best all round drivers in multi terrain I have coopers on my land rover D2 in the uk and BF Goodrich on my Landcruiser in Australia both awesome tires and very capable. Too many people trying to look cool in their Chelsea tractors or shiny 4b that has never seen any corrugations or a bush track I'm with you Andrew for guys like us doing real long distance outback driving I think 285's are the most width you need... Thanks for your videos keep up the good work 👍🇦🇺😎
Hi Andrew, love your vids and expert advice. In regards to the rock climbing I understand what you're trying to say (and demonstrate), but I think the pointy part of a rock will have the same pressure on it regardless of tyre width. Also, think about human rock climbers, they generally open their hands wide for maximum grab when they're pulling themselves up, they don't squash their fingers together and try to grab narrow (unless its a smaller knob of rock).
You're right A lot of these Australia and British guys sinking in. As an American I see something I friendly refer to as British overthinking it's when they come up with something and they all repeat it enough to each other and they all go for it but in real life it just isn't true and the theories do have truth like shallow mud or shallow snow but overall when they say skinny is better at everything it is just a British overthinking
Wider tires hold the wheel bead better when you air down and also increase your lateral stability. I think the smaller the wheel the better, as long as it fits over your caliper. I use 15". I like most of your points though, not sure about the sand portion though. Narrow tires are definitely better considering varying terrain imo.
SuperCellProductions which is mostly irrelevant because you get more tread compliance in narrower tires at higher internal pressures because it has more psi on the contact patch. The conformity of a narrow tire at 15-20 psi is likely to be the same or better as a wide tire at 10-15 psi. You don't need to air down to silly bead locker psi on a narrow tire to accomplish the same task... Most of the time. The lateral stability I is overrated I think. To the degree it's not you could use spacers or offset wheels to accomplish the same thing if it really mattered that much. If somebody did the rollover Calc of narrow to wide tires I bet we are only taking tenths of a degree of increased side angle stability. Personally I think sliding at those angles from loss of traction gets you into more trouble than having a little extra side angle stability before rolling. Most people freak out way before there side angle roll over point anyways so it would be hard to capitalize on any benefit.
Sure, I had to embellish a little bit to think of some pros of wide tires. I'm sure pros are minimal, then again all these talking points are. I've personally barrel rolled my jeep before, so I just like the security of big offsets with my wide tires for now, even if it's false security, though I sometimes go down to 2psi in snow and have never lost a bead so take that as you will. You sound like the resident tire expert of this thread. I've been thinking about getting some super narrow boggers as my next set though as I definitely attest to narrow tires performing better overall.
Thanks for a great video and information . I am about too put new wheels and tyres on my jeep and you helped me a lot . Dont think you would remember me . We met briefly on the way from Cape town to Jhb at a stop and go . I informed you a light was out on your Land Cruiser that you we're taking too the Getaway show. Hope you have safe travels and love your channel
On point as usual Andrew. However there’s another factor as well as rolling resistance and traction. Ground pressure. This probably doesn’t relate so much to a long contact patch but obviously the less ground pressure is gonna help a lot in soft/sinky terrains.
Andrew, If you like the KM3 but dislike the width of the "test" tires I'd point out that the KM3 is available in 255x75 for 16" or 17" wheels. There are also 265's in various aspect ratios and wheel sizes as well as 245, 235, 225 all in 75 aspect ratio among others. How narrow do you want to go?
Great video Andrew. I was going to put 235/85r16 on my vehicle yet I went with 265/75r16 for 2 reasons. Reason 1 is cost, the 265 was cheaper by about $40 per tyre. Reason 2 is availability, in my experience here in Western Australia 235/85r16 aren't a common size so at a lot of tyre shops especially in country towns need to be ordered in, most seem to stock 265/75r16. Like everything on our vehicles it's a compromise.
6 лет назад+2
Hello Andrew, thank you for this inspiring video.I'm a bit confused hearing you say that wider tyres are more comfortable on the road. To say that, the road would have to be perfectly flat. In (my) reality, wide tyres cause the road bumps to feel harder, the tracks in the road surface will pull the steering wheel more and if too wide, rain will become straightforward dangerous. The only nice thing is better grip over corners, but I wouldn't call it comfort at all.Anyway.... on the Mitsubishi L200 (Triton) I used to drive in coal mines we used to use 205/80R16. Nobody of the 4WD fans here even mentioning such a skinnies. Is it something completely unusual for you guys to use it?
I agree , but with tyres need to be a certain size imo to suit the vehicle size, power, and gearing. If you have a 1000 hp with skinny or small tyres there would be not point. The bigger the tyre requires to get the best out of its Power and or gearing. IMO the optimal tyre for a land cruiser troopie would have a 285/65/16 (or eq) and a Hilux for example would be a 265/75/16 (or eq) If you have either vehicle with heaps more power and say lower gearing you would get more off road performance with bigger and WIDER tyres. Just my opinion and personal experience.
In my opinion, one of the reasons as well to go with narrower tires is that it's cheaper. I have observe a significant drop in fuel economy with wider tires. On longer trips, fuel economy is important. That's the reason why I went back from 285/65 R17 to a 265/70 R17 (Cooper Discoverer AT3). Plus it's cheaper to buy but the wider tires in my experience gives me greater stability in clay type mud. Of course, this is just my experience. Btw, thank you as usual Andrew for a very informative video and I will definitely keep this in mind when I get a taste of sand. Cheers to you sir! 😉
Stop the arguments! I agree. I run a narrow tire myself. They will work better for 90% of my personal driving situations. I can work out the other 10%. Wide tires just do not give good traction in Decomposed granite. The higher ground PSI of a narrow tire helps out a lot. Thanks for the video. Arguments proceed.......
So I use 235/85r16 here in upstate NY. We get a LOT of snow here and they’re fantastic! Next spring I’m gettin some MTs in the same size. Lots of snow in the winter = lots of mud in spring.
You seem to be tying yourself into knots over this, as will most comments in this video. However it is very good that you are raising the issues. You are absolutely correct that its not as simple as size equals grip, it is also about pressure (applied by the weight of the vehicle) per square cm. There is an optimal balance dictated by one's requirements. Good one!
I generally agree with your perspective re narrower tyres Andrew, but some details in your explanations and analogies ring hollow. Would it be possible to arrange for a knowledgeable *engineer* from your tyre company contacts to give us a run down? That would be awesome. Perhaps a one on one interview posing the same scenarios and seeking his/her explanations?
Thanks once again Andrew , it was great to meet you in Melbourne , also I’m interested in a review about roof rack , rear wheel carrier and more about tyres ie fuel consumption ect
235/85-16 BFG KO2's on my 04 Jeep Grand Cherokee. Lifted it 3" and trimmed a little to get them to fit, they are noticeably better than the previous 265/70-16 I had on there.
Being from Minnesota, I concur with everything you said except you forgot to mention compound. A winter tire with a softer compound is the most important aspect of a winter tire.
Interesting discussion. I think you are leaving part of the tyre function on the vehicle. The tyre function is based on the weight of the vehicle in the terrain. Have you revealed the weight of the troopy, the standard kerb weight is 2385, GVM of the std troopy is 3300kg. The difference between something between a common vehicle like a HiLux or DMax compared to the way heavier Troopy would make a major difference of tyre functions. (HiLux 4x4 is kerb 1850kg and GVM up around 3000kg)
Live in Alaska I agree 100% with the snow tires,wide tires cause flotation zero grip and are a recipe for disaster but beach driving with a heavy load wide tires are a must
As for rocks, check out the Rubicon Trail, Moab Utah and all the good 'ol boy rock crawling down in Tennessee. Low pressure to increase contact patch, wide width to increase contact patch. More rubber on the surface = more traction.
@@4xoverland I agree that wider tires are better on rock, particularly sandstone. Coming from a rock-crawling background in Moab, it's known that having more contact between rubber and rock results in better grip. It's worth taking a look at the wide tire widths used by competition rock crawler teams who take the technology very seriously to gain an edge. Cheers.
Some good info in the video. I too believe that each vehicle will have a "sweet spot" to do with its weight, stance, power, flex and materials used. Some much of engineering is trying to get your machine into that effecient sweet spot. Slapping large tires on, or boosting power is only changing one part of the cog so to speak. There will be a sweet spot regarding tire size that will match your vehicle. It may be different for each individual vehicle too. Once you find it it's best to stick with that. It will be good at somethings but let you down in other areas but that's what works best for your vehicle. Changing even tread type has a dramatic effect on the vehicle as a whole as every part is working together or against each other. The sweet spot will have fairly thin tires that can be for sure. That's why he mentions the arctic trucks having very tall tires to offset the width basically still making them a thin tire for the vehicle.
I've said this before and its worth saying again - You are correct regarding width for performance off road but its ignoring profile. a 9 inch wide tire will perform well but if its an 85 series sidewall you are going to lose lateral stability at high speed. Air pressure supports the weight of the vehicle vertically but the sidewall stiffness controls the lateral stability of the vehicle and the taller the tire the less there is. You can add more air but its the sidewall that's doing most the of the work, not the air. Meaning in an emergency situation a heavily loaded touring wagon is going to be less stable and more prone to loss of traction and control. Even in heavy cross winds at high speeds you can feel the difference. Where I live most of my touring is separated by long stretches of 80 mph freeway and while my 285/75r16 might not be the best tire in terms of width, they offer greater on road stability in those situations. The tradeoff is worth it to me.
You make some very good points. In fact, it requires a very good motivation or special use situation to venture away from the sizes chosen by the manufacturer for the vehicle. It is not necessarily 'bigger is better'. In my own case with a 76 V8 wagon (265/65X16 standard) with all terrains and living in a farming area I was tempted to go to 285/75 X16 for some extra diff height without doing extra lift. Our local tyre supplier advised against it for all the reasons you discuss, but did advise me to rather change to 265/75 X16 when the first set was worn. The reason? They are the most common size 16 inch tyre available in the sticks here! The average farmer here pounds his usually overloaded 79 over rocks and potholes daily and they do not like wide tyres. So I fitted Dunlop ATR3 (3 ply sides) and managed an 8,000km trip around Namibia towing an off-road caravan without a single puncture or tyre loss. On the hard I ran them on spec pressures, whereas on hard gravel I went down to 2.3 Bar and 1.8 Bar nominally. If I even smelt sand I was 1.6 Bar all round. Why no lift? Besides not needing the extra height, it would require me to modify my garage entrance height. I think not. Did you ever see one of the 15 million Model T Ford's on balloons?....and that was before there were proper roads.
Remember when he tested a black Jeep Rubicon at the United Arab Emirates in the soft sand and those tires were 12.5 inch wide well it never got stuck and it could roll right up those Hills nice and slow from a stop but skinny tires have to keep momentum to go through this and who cares about drag they're going to sink in if you have the power you're not worried about Dragon worried about floating over-the-top this is what I call a British overthinking
I drive 35" M/T for the past six years on many Desert Crossing on tracks like the French, Madigan etc but also quite a few remote Cross Country Desert crossings without tracks, not to mention plenty of beach driving on Fraser, Moreton, Stockton, Blacksmith and so on... I yet have to get stuck. Interestingly any Desert bicycle rider will choose the biggest fat tyres they can ride (on a bike that has it's limit as you only have one Man Power). In a car however it has little practical bearing as long as you have correct tyre pressures as nearly any modern car has enough power to push the little sand in front and the longer footprint and wider tyres compensate amply with plenty of traction even at low speed. On our last 3 Desert Cross Country trip the only vehicles not stuck where solid-axle LandCruisers with 35" wide M/T tyres. Have plenty of videos on my chancel which demonstrates that. A narrow tyre is better for rock climbing? Hm I have yet to see you do any rock climbing or having a vehicle who could do this. I go technical driving once a week and that is 95% rock and wide tyres are certainly better as they give you a bigger contact area to latch on to. Wide tyres do no sit there and spin where narrow tyres don't if they have the correct pressure. Have yet to see a purpose build rock crawler in any competition on narrow tyres most guy's there do that for years and have tried every conceivable constellation.
@@gabi.2.1 what do I see tough? Moab is a Rock Desert, can you drive it with Pizza Cutters? sure you can and for certain tracks and lines, some people use them but in general wider tyres better grip as long as the vehicle is set up for it.
I have owned 30 4x4s and have tried out many tyers and terrains.Currently i run a twin arb locked zd30 patrol on 7.50r16 Michelin XZL’s.The thing will go where you point your steering wheel.Also is impossible to get a flat tyer on them,even sharp river rocks can’t stop them.
Racing swamp buggies have tall narrow chevron pattern tires. Some UTV's mimic them. I went on a tag-along and watched a 60 series play in a swamp with 33" tires. It allowed him to move back and forth without sinking down and crossed it. 33's were the accepted norm. in this club.
This video arrived at just the correct time, because it's time for new tires and wheels for my Ford E250 Van, and i have been planning on getting BF Goodrich AT's. But two different sizes are available for my vehicle, one is wide and low profile and the other narrow and taller... thank you.
As a KO2 owner I say find something else...they've never gotten me stuck but they are just alright everywhere, except wet road in which case they are scary.
I've been a little concerned about having to go to a narrower, slightly taller tire in order to fit all terrain tires to my stock 16" rims, AT's aren't made in my stock tire width, and this eases my mind considerably.
I'm glad you've been able to convince yourself that narrow is better than wide. I've been struggling with it for decades. The big difference between us is that I don't deflate my tires off-road. I guess I'm just too lazy. I've experimented with 235-85 17 on a full-size pickup vs 265 75 and on my FJ Cruiser I tried 255-75 vs 265-70. I never do any sand driving anymore. But we have our winters with lots of snow and ice. I still think the wider gives you better response with handling braking and acceleration just about everywhere at full tire pressure. I think the narrow tire will loose traction more quickly when rolling over smaller rock because it acts as bearings and lifts most of the tread off the ground where the wider tire will confort a little better and retain more traction (at normal pressures). The pickup with narrow tires would spin more readily on just about any surface. Of course my opinion is still a guess because of the advancements in compounds over the years but I went through 5 sets of tires with the pickup and 3 on the Cruiser probably another 4 on a Ranger. I never deflated on dirt because my speeds were often too high. On ice and snow I also kept normal pressures because I wanted the studs to work efficiently which they do. SO... in the end I tend to go on the wide (stock) size purely for the extra traction in emergency situations in every day driving. Modern vehicles with all the safety electronic nannies are calibrated towards stock size tires and I don't want to risk loosing their effectiveness through tire widths.
Thought that would be your view and i agree. But how did you find the noise coming up from Melbourne to Ipswich i didn't get to ask you at the Ipswich meet and greet the sponsor seamed too be taking up your time, it was good to see you and your daughter there.
Got a 100 series Cruiser, stock tyre is 275/70r16 (31.16"). Lots of guys go up to 285/75r16 (32.83") but I'm thinking of going 265/75r16 (31.65"). Opinions? Should I try stick with the stock size? Noting that there are less tyre options at the stock size.
Appreciate the video Andrew! What’s your opinion on 15” wheels? I would assume, if you can fit them, they would be better than 16” or 17”.
6 лет назад
If you can fit 15" wheels, you have brakes of no use. :-)I run 15" alloys on my old Vanagon 4WD, orignally wanted to use 215/75 R15 but because of weak brakes I sacrificed some clearance and went for 205/70R15.And then guys, try to beat my narrow tyres! :-D
Fully aligned! Also prefer narrow, especially for sand! Runed 235/85 on a kzj95 in sand and it performed great!.now running 255/85 R16 on a Y61 lwb and also expected to perform great. The only downside is road handling, but you get a better fuel milage! Great review!
Maybe week or engines and lighter vehicles are better with narrow in the sand because he tested that black Jeep Rubicon in the sand and those tires were 12.5 inches wide on the dunes and it could literally stop at the bottom and go up huge hills without sinking because of the flotation of a wider Tire. I have tested skinny and wider in the Sugar Sand we have here in the desert of Arizona that is extremely loose thick grain and hard to walk on it doesn't pack the way Dune sand does when you push on it it is completely loose and my 285 75 16 perform much better than skinny tires that just sink in. That's why dirt bikes and ATVs have pretty wide tires for how dramatically like they are under 300 pounds. The whole drag Theory makes no sense unless you're driving some old Toyota or Old Land Rover with no power but all the most powerful newer vehicles with wider tires float right over sand like nothing they don't have to keep momentum to keep going that literally proves it's better.
I aired down one snowy night ,2 inches, and it did offer better traction. I have always thought skinny tires were good for snow. Did that larger contact patch help me out that night?
The narrow front tyre on a tractor has one feature that you do not mention. They usually have three straight groves that are aligned with the direction of the tire. The object of the three ridges is to direct the dirt or mud into the areas between them and that allows them to float above the muck and still have the sharp edges contacting the main strata so that they can turn with ease.
I've noticed in muddy condition, a skinny tire might be beneficial as it cuts through the soft mud and reaches the bedrock underneath to give better traction, rather than float on top and getting packed with mud.
Agree, I put 235/85 16 on my Pajero ( second Gen) instead of the original 265/70 15. Much better in every Offroad Situation, but on Tarmac the skinnys sucks a bit. Great Vid.
Another great video Andrew. I think a good part of the tyre selection problem is advertising hype .. ie. wide tyres are the current 'fad'. They look good because everybody else says they look good ... just like when you go to by a 4x4 .. everyone wants a Toyota. Everyone wants a Toyota because everyone else tells them that they need to get a Toyota ... without 'really' knowing what they're talking about. Don't get me wrong ... vehicles like Landcruisers are very capable 4x4's .. they're just not necessarily 'the' 4x4. When you buy a new LC the first thing that people do is get rid of the factory wheels and put 'huge' tyres on them because that somehow makes them much more 'capable' and 'macho'. Due to a lack of knowledge .. and experience .. many people purchase every accessory they can get their hands on because that's what you 'need' to have a good 4x4. You only need to look at the range of accessories that are in the 4x4 stores now .. along with the ridiculously high prices. And people just pay it!!
Most off road tires today at a 33 to 35 inch tire range have a 12.5 inch cross section. Years ago you could get those same tires in a 10.5 inch cross section.
Old Griz Yeah but the rubber compound on intercos is from the stone ages lol. You couldn't pay me to drive those tires on wet pavement, snow, the highway lol.
They way I think of tires is in biting edges. How many biting edges do you need for the terrain? A major factor as well is vehicle weight. The other factor is how much force will your terrain support per inch
Key to this whole lecture @8:28. I like tall-skinnies on light vehicles with low power (Zook) Vehicles with higher power (Steering, Brakes, Engine) I like a wider tire. I can deal with as large of a rim as a 20" as long as the tire is a 37" or larger. 17s are the norm for most here in the states anymore with the size of the brakes that come stock. For a 17" the lowest diameter I like is a 33" tire on an off-road vehicle. On the STT Pro I like the 12.50 over the 13.50.
I went from 255 mud tires to 305 and they were terrible. Always floating through corners in the mud and just squirming about where my 255's just cut through and drove like it was on rails in comparison. The 285's I had next were a good size as well, but taller than average as they were 285/75r18 and on a very heavy truck. Despite being an uncommon size in North America I"m back to 255/85r16 but I have yet to get off road much with this tire yet.
I am in agreement with you Andrew. I have spent many years in the military driving just about every kind of vehicle you can imagine from small 4x4s, medium and large 6x6 trucks, tank transporters and amphibians in every environment. People just need to look at the tyres that the military use on their vehicles and realise that millions of miles have gone in to testing tyres they use for the best and worst of conditions. I can tell you that nearly all of the tyres are of the taller sidewall thinner profile and mostly with an all terrain tread pattern type. Go look at what the military use and make it an easy decision.
About the rocks(rock crawling) while you are correct to a point. However in America where they build rock crawlers all day long with wide 40 inch tyres and wide axles and narrow bodies. They do it for it stability. What they do, where they get to and the obstacles they do you're not going to get a Overlander type 4x4 on skinny tyres near these these things. It's apples and oranges. I run a wider tyre and I prefer it for rocks and feel like I have more grip.
it would be nice to know how far you let the pressure down on a rim, i suppose that heavy trucks could be in trouble at very low pressure, bead lock rims are commonly used in the US, are them really better? My truck is quite heavy and running 17" rims i'm worried about let the pressure too low especially during sharp turn while offroad, so the only way out for me is to go wider tires, what do you think about?
So, it is mostly about the percentage of a tire's radius that falls below the tracks surface. As that percentage increases, the rolling resistance increases as well, until it meets up with the tractive force, leaving you stuck. Also, in certain circumstances, the greater the percentage of radius that the tire has sunk to, the more power it will take to pull the trailing side of the tire up out of the material it is buried in, which will also result in some downforce on the tire. It certainly does no good to have the leading, and trailing sides of the tire fighting against each other. In certain circumstances, wider tires will make this problem worse. However, increasing the diameter of a tire means that for a given depth you have sunk, the percentage of radius below the surface will be lower.
Andrew, thanks for this video. I am looking at buying a new set of tyre for my LC79 DC. I have narrowed the choices down to BF Goodrich AT KO2 265/70R16 and the 235/85R16. The height of the sidewalls are 265/70 is 185,5 vs the 235/85 is 199,75. I selected these tyres because both are 10 ply tyres which should help me against punctures in the Tankwa. I understand that the ride comfort is going to suffer. My concern is that I also do lots of Namibia dunes so I need good performance in sand. I am leaning towards the 235/85 because of the higher profile which I believe is going to give me a longer footprint at low pressures. What is your opinion?
Thank you. Really enjoying the explanation of so called 'simple' overlanding topics. It's comforting to have an expert opinion you can trust. Looking forward to more.
If my load per tire was 1000 pounds and my tire max pressure is 50psi at 2000 pounds. Does that mean I should always run between 25 and 50psi? Would it be ok to run less than 25psi at slow speed off road?
Actually changed my tires because of your recommendation .. and I had a major problem: I have a 2001 Ford Explorer 2Dr Sport and I have run two sets of BFG KO2's in 285/75 16" getting over 40K miles on each set. I decided to try the BFG KM3's in 255/85 16" .. They seemed to work well but coming back from a recent road trip something wasn't right .. took it to my mechanic and decided to rotate and rebalance the KM3's .. well, they couldn't be balanced! 7052 miles and the tires are junk! At Jack Furrier Tire here in Tucson they tried to rebalance them with no luck .. there was a definite 'hump' in each tire as it spun .. like the tire was hitting a bump? I never even got a chance to air them down. Put on a new set of BFG KO2's like before .. problem solved. I sent a email to BFG .. we'll see what they say.
Tyre technology might have changed with improved materials and modelling techniques but the traction and offroad formulae for different types of terrain is still based on the formulae developed in WW2 with just a few tweaks in the 50s-70s... you've got mechanical engagement, friction and rolling resistance all balancing off each other and all affected by many variables.
I wanna see a guide video from this man on long distance tarmac driving on stock vehicles. Helpful tips on accessories or things to keep in the vehicle to make driving easier without turning the while vehicle into an overland tourer.
I agree partially with what you say but too many variables. I agree Pressure on a narrow tyre may be more but friction increases with more rubber on the surface. A wide tyre on rocks also helps straddle rocks where a narrow one might get caught in a crevice or slide off more easily . Also width of the rim impacts on drivability as a narrow rim on same sized tyre hold the tyre better than a wider one imo.. finally at very low tyre pressures, we talking 8-12 can increase width of contact as well as foot print length..
So Andrew what are your thoughts with regard to the commonly available tyre sizes for 4x4's at the moment? It seems to me there's a distinct lack of tall but narrow options! I'm a fellow troopy owner and I've always enjoyed and seen the benefits in narrow tyres but if you want to go slightly taller you have to go a lot wider and the few exceptions available are only in certain tread patterns (for example BFG makes a 255/85r16 but only in a mud tread not all terrain)....
true about the old tractors ... but the new tractors in USA have very wide tires , I mean gigantic wide tires ... front and back ... why ? I wonder if they went with narrow tires in the old days because the rubber was more expensive and also the manufacturing process ... possible maybe ?
Brilliantly said, Andrew. You hit all the points I have used in explaining why I run a 235/85/16 on my Toyota Tacoma; save for the difference in our accent. My prior tire size was 285/75/16. I noticed a lot of difference in performance when I made the switch. I have driven in 3.5 feet of fresh, powdery, virgin snow, aired down to 8psi. I have gotten four other Toyota drivers to switch to narrower tires and they all appreciate my encouragement. Keep up the informative and entertaining videos.
Check my vehicle on my channel i copied u
I know your comment is more than 3 years old, but I run the same size tire on my '06 Sequoia. Performs well, and has slightly less rolling resistance on the road than the stock size. Gives me a whopping 0.5" inch of lift, too.
Here,here Andrew , I am a Canadian and have driven Jeeps for the past 40 plus years . Narrow Tires are the only way to go in our winter conditions and on our logging roads and trails during all seasons.
You sir just answered ALL my tire questions and arguments. I salute you Andrew.
Well Andrew, you and Ronny better do an comparison episode on this. And give us the ‘facts’ and put this to bed. 👍
Yes!
Why involve Ronny?
Davin Ellicson. so! Heaps of popular 4x4 bloggers / vloggers (or whatever they call themselves) run 35’s.
Because ronny and andrew are good mates
ParKKos97 . “Good mates”! Lol.
Snow driver here. I'd say you're pretty much right on with snow. The only time I or anyone I know would care about flotation is if the snow gets much deeper than the axles. If you're building a glacial expedition-specific vehicle, sure, but it'll suffer in almost all other imaginable driving conditions. (BTW they're often 6x6's for an even larger footprint too.) As with most things, it is compromise. There is no single go-anywhere best in all conditions/environments tire.
This just might be the the most intelligent and accurate discussion on tire size and pressure on RUclips with regards to 4WD, and more. I look at the ‘thumbs down’, there are a lot of ignorant and brain washed folks out there thinking wider is “always” better with traction. Americans as a rule, and I am one of them, think bigger is better and this surely is pervasive in the 4WD arena. Your points concerning the critical aspects of PSI per square inch is so misunderstood and in most cases ‘not’ understood, is exactly why so many people don’t understand, get or have real world side-by-side experience with this concept. Maximizing PSI down force, 99% of the time, is the most important variable to manage. It is a balance of course but far to often we go too wide and loose that magic balance with PSI downforce. Besides a 4 wheeler I am a farmer. So, I have heavy duty trucks (besides my beloved Jeep), aka one ton pickups.. Some are single rear wheeled and some are dualies . I live in Michigan; sand, mud and snow...traction is always an issue. No one drives their duallies unloaded in any of these conditions unless you remove one of the rear dual wheels because they just flat out get no traction. Not enough downward PSI spread across all that rear rubber. Removing one wheel or driving the same truck but not a dually is not a traction issue. Same physics and principles apply to traction in 4 wheeling, as a rule.
Swapped out my 285/75 16" KO2's a couple of days ago and went with the
255/85 16" 'skinny' KM3's .. I did a bit of research on these tires and
was a bit worried that they would be loud .. not the case .. no louder
then the KO2's. I was told that the one downside is that they don't
handle as well on ice! I live in Tucson,AZ .. don't think I'll have to
test that. Your testing and presentation on the 'skinny' sold me .. so
thanks!
Hey I live in Tucson Arizona also I drive a disco 2 with grey bed liner body finish and a black roof. Anyway I run 285 75 16 and I swear if I'm down in the Rillito wash when it's super dry in the summer I can roll through any of the thick sand where no one has driven and come to a stop and take off just fine when skinnier tires seem to sink in forget the rolling resistance if you have the power and really my disco doesn't have a bunch. So just curious how do you feel about that now three years after this post when you ran Skinny's?
I've been thinking this direction for quite a while but never heard it explained this well backed with this much knowledge. One of the most informational videos I've ever watched thank you.
Started researching this more after your other video on choosing a skinnier tyre. Has absolutely blown my mind, and completely changed my understanding of offroad tyres. I've been preaching this to all my 4x4 mates since. Safe to say I'm ordering some skinnies for my car in preparation for a big trip in a few months. Great video and explanation!
Excellent video, thank you. 15:45 Our tractor, tall five foot 1.5 meters tires, narrow tires, to increase its grip, we lifted the axel to where both rear tires were just off the ground. Turned the rear tires so the air stem is at 12 o'clock then removed the air stem insert. Although all air escapes the robust sidewalls held the tire on the rim. With an adaptor connected to a water hose to the tire air stem filled both tires until the water overflowed the stem; returned the stem insert. Notice, there is now an air gap at the tire top. Connecting the air hose, we pressured each tire to 15 lbs. or 1.03 bars. Even after using the subsoil plow and turning plow, producing very soft fluffy soil for planting, the tires weight and narrow width provided tremendous grip to the ground. Water did not leak, we always maintained the correct air pressure; to check the tire pressure turn stem to 12 o'clock. The front tires did not contain water, much smaller diameter eighteen inches or so, and very narrow tires maybe four inches, 100 mm, pressured to 30 PSI, 2.06 Bars. As you stated, turning the wheel the tractor went where it was pointed, and the tractor was firmly planted on the ground, narrow tires all around.
I drive a semi truck, long haul here in the US. I didn’t have to watch past 1:15 rolling resistance and traction are the only things that matter to me as well. As a matter of fact rolling resistance is more important than even tire life. Reason being you spend so much less in fuel, if you get the right tire that it overcomes the lower tire life if that is even what anyone might contend. Got my sub love your content.
Excellent video! As always, thanks for sharing your wisdom.
Also, submitting "Squinch" to Marriam-Webster as the new standard for any usage of square inch.
Another comment about tractor tires, a major reason tractor tires are wide is the fact you need huge area of tire to reduce pounds/sq. in preventing compaction of the soil in the fields. Dense soils are less suitable for crop growth.
Indeed. Probably thinking of an old Massey Ferguson Model 35!
This video help me decide to get a taller but thinner tire. From my 265/70R17 (10.4“ wide, 31“ tall) tire I’ll go for a 255/80/R17 (10” wide, 33” tall) tire. Looking forward to seeing the difference in performance.
@kiddomike after this many years, what's your feedback on going to 255.
How did you like those 255s?
Dropping the "things have changed Mate" like a regular Aussie already
Hi Andrew. Not sure if I agree wholeheartedly but as usual I'm super grateful for your experience-based opinions on all things overland! Well done and thanks for sharing.
We need some science! ‘Fat’ or ‘thin’ isn’t enough. We need weight to tire width/size calculations on a spreadsheet :)
The underlying equations are a bit complicated for a spreadsheet but can be coded up in any competent programming language. Refer to my comment above and the video. This aims to address the points you have raised.
Rolling resistance is smallest when the tire deformation is smallest (less deformation means less energy goes into heat). Smallest deformation will have a contact patch with the form of a circle, i.e. flotation tires (one that ends with LT) as their contact patch has a ameboid form. For non flotation tires the closest to circle will be square surface patch. If we take sand for example to have a good flotation one need to run about 0,7 bar. If the truck has weight of 750kg per tire that means a contact patch of 750/0,7=1071 sq.sm. If we take square root makes 32,7sm, or 12,88’ wide tire. Making a reality check by looking at competition tracks about 2,7 tons run 37x12,5 inch tires so theory is confirmed by practice.For flotation tire to have circle contact patch you need 14,5 inch wide, as area of circle is 3.14 times r times r. Good Luck.
Pascal's= force/Area squared.
It was the same story when I was in a mountain biking club, the cyclocross bikes with very narrow tyres were way better on the mud. Still, I got 305/70/16 for my overlander despite knowing they're "too wide", why? I just love the look of them, its that simple.
I run 255 85 16 on my troopy.
Something you didnt touch on is that with narrow tires in deep sand ruts the side of your tyres dont rub on the ruts and you dont lose revs or momentum.
Thanks for the update Andrew. I'm fairly new to the overall 4wd/overland scene (been hovering around the edges for years but only dabbling) and your videos have been a big help. I would be curious to hear your thoughts/comments at some point on setting up a vehicle that also needs to regularly commute (I don't recall a video on this - if you have done, forgive my ignorance) as I'm at the point now of having to either 1. Keep the old clunker 4wd that has had a hard life + passenger car or 2. Convert into one (likely Prado or similar size). Your comments on how far tyres have come just twigged this in my head as I've always wondered what people run on their daily driver 4wd. Surely something like that KM3 is better than MT of the past but it must still substantially impact fuel economy/road manners? Is the better option two vehicles each for their specified purpose or is a single vehicle viable by using two wheel sets and removable equipment (draws/tanks/containers etc.) the better course (my worry with which is both weekend damage + the work involved to kit it back up every time you want to go somewhere)? Is a definitive answer even possible? As I said - just curious on your opinion.
Interesting talk, thank you. Weight also has to be taken into consideration, as well as rolling resistance when using wides, I.e., putting the drive components under more stress when accelerating or when tyres are spinning, especially when using steel wheels. I use 235 85 16s. I think a lot of folk use wide tyres for looks, which I agree, certainty do make the vehicle look the part and that's fair enough.
I can only comment on my experience over 30 years driving mainly in the UK and Australia many other countries but the main two I have done heaps of bush / trail driving and found 285/70/16 to be the best all round drivers in multi terrain I have coopers on my land rover D2 in the uk and BF Goodrich on my Landcruiser in Australia both awesome tires and very capable. Too many people trying to look cool in their Chelsea tractors or shiny 4b that has never seen any corrugations or a bush track I'm with you Andrew for guys like us doing real long distance outback driving I think 285's are the most width you need... Thanks for your videos keep up the good work 👍🇦🇺😎
Hi Andrew, love your vids and expert advice.
In regards to the rock climbing I understand what you're trying to say (and demonstrate), but I think the pointy part of a rock will have the same pressure on it regardless of tyre width.
Also, think about human rock climbers, they generally open their hands wide for maximum grab when they're pulling themselves up, they don't squash their fingers together and try to grab narrow (unless its a smaller knob of rock).
You're right A lot of these Australia and British guys sinking in. As an American I see something I friendly refer to as British overthinking it's when they come up with something and they all repeat it enough to each other and they all go for it but in real life it just isn't true and the theories do have truth like shallow mud or shallow snow but overall when they say skinny is better at everything it is just a British overthinking
Good ramble there Andrew. I learnt a lot. Cheers
Wider tires hold the wheel bead better when you air down and also increase your lateral stability. I think the smaller the wheel the better, as long as it fits over your caliper. I use 15". I like most of your points though, not sure about the sand portion though. Narrow tires are definitely better considering varying terrain imo.
SuperCellProductions which is mostly irrelevant because you get more tread compliance in narrower tires at higher internal pressures because it has more psi on the contact patch. The conformity of a narrow tire at 15-20 psi is likely to be the same or better as a wide tire at 10-15 psi. You don't need to air down to silly bead locker psi on a narrow tire to accomplish the same task... Most of the time. The lateral stability I is overrated I think. To the degree it's not you could use spacers or offset wheels to accomplish the same thing if it really mattered that much. If somebody did the rollover Calc of narrow to wide tires I bet we are only taking tenths of a degree of increased side angle stability. Personally I think sliding at those angles from loss of traction gets you into more trouble than having a little extra side angle stability before rolling. Most people freak out way before there side angle roll over point anyways so it would be hard to capitalize on any benefit.
Sure, I had to embellish a little bit to think of some pros of wide tires. I'm sure pros are minimal, then again all these talking points are. I've personally barrel rolled my jeep before, so I just like the security of big offsets with my wide tires for now, even if it's false security, though I sometimes go down to 2psi in snow and have never lost a bead so take that as you will. You sound like the resident tire expert of this thread. I've been thinking about getting some super narrow boggers as my next set though as I definitely attest to narrow tires performing better overall.
SuperCellProductions No just a pet peeve issue and I have a cold and can't sleep. Lol I should probably shut up and stop posting though lol.
Thanks for a great video and information . I am about too put new wheels and tyres on my jeep and you helped me a lot . Dont think you would remember me . We met briefly on the way from Cape town to Jhb at a stop and go . I informed you a light was out on your Land Cruiser that you we're taking too the Getaway show. Hope you have safe travels and love your channel
Thank you for the best birthday gift I've received today. A new upload of yours full of knowledge and enthusiasm.
On point as usual Andrew. However there’s another factor as well as rolling resistance and traction. Ground pressure. This probably doesn’t relate so much to a long contact patch but obviously the less ground pressure is gonna help a lot in soft/sinky terrains.
squinch! hahaha. love it. no need to correct yourself.....that's the perfect term!
Andrew, If you like the KM3 but dislike the width of the "test" tires I'd point out that the KM3 is available in 255x75 for 16" or 17" wheels. There are also 265's in various aspect ratios and wheel sizes as well as 245, 235, 225 all in 75 aspect ratio among others. How narrow do you want to go?
Lyle Herbert : There is also an 7.50 r16! Roughly 205/100 r16 or about 32 inch.
Great video Andrew.
I was going to put 235/85r16 on my vehicle yet I went with 265/75r16 for 2 reasons. Reason 1 is cost, the 265 was cheaper by about $40 per tyre.
Reason 2 is availability, in my experience here in Western Australia 235/85r16 aren't a common size so at a lot of tyre shops especially in country towns need to be ordered in, most seem to stock 265/75r16.
Like everything on our vehicles it's a compromise.
Hello Andrew, thank you for this inspiring video.I'm a bit confused hearing you say that wider tyres are more comfortable on the road. To say that, the road would have to be perfectly flat. In (my) reality, wide tyres cause the road bumps to feel harder, the tracks in the road surface will pull the steering wheel more and if too wide, rain will become straightforward dangerous. The only nice thing is better grip over corners, but I wouldn't call it comfort at all.Anyway.... on the Mitsubishi L200 (Triton) I used to drive in coal mines we used to use 205/80R16. Nobody of the 4WD fans here even mentioning such a skinnies. Is it something completely unusual for you guys to use it?
I agree , but with tyres need to be a certain size imo to suit the vehicle size, power, and gearing. If you have a 1000 hp with skinny or small tyres there would be not point. The bigger the tyre requires to get the best out of its
Power and or gearing.
IMO the optimal tyre for a land cruiser troopie would have a 285/65/16 (or eq) and a Hilux for example would be a 265/75/16 (or eq)
If you have either vehicle with heaps more power and say lower gearing you would get more off road performance with bigger and WIDER tyres. Just my opinion and personal experience.
In my opinion, one of the reasons as well to go with narrower tires is that it's cheaper. I have observe a significant drop in fuel economy with wider tires. On longer trips, fuel economy is important. That's the reason why I went back from 285/65 R17 to a 265/70 R17 (Cooper Discoverer AT3). Plus it's cheaper to buy but the wider tires in my experience gives me greater stability in clay type mud. Of course, this is just my experience. Btw, thank you as usual Andrew for a very informative video and I will definitely keep this in mind when I get a taste of sand. Cheers to you sir! 😉
Stop the arguments!
I agree. I run a narrow tire myself. They will work better for 90% of my personal driving situations. I can work out the other 10%. Wide tires just do not give good traction in Decomposed granite. The higher ground PSI of a narrow tire helps out a lot. Thanks for the video.
Arguments proceed.......
So I use 235/85r16 here in upstate NY. We get a LOT of snow here and they’re fantastic! Next spring I’m gettin some MTs in the same size. Lots of snow in the winter = lots of mud in spring.
I’m ready for some travel and camping. Get that Troopy in the dirt. But still a great and informative video. Thanks.
You seem to be tying yourself into knots over this, as will most comments in this video. However it is very good that you are raising the issues. You are absolutely correct that its not as simple as size equals grip, it is also about pressure (applied by the weight of the vehicle) per square cm. There is an optimal balance dictated by one's requirements. Good one!
Verry interesting Mr White, thank you. Please continue making this type of experiences!
I generally agree with your perspective re narrower tyres Andrew, but some details in your explanations and analogies ring hollow.
Would it be possible to arrange for a knowledgeable *engineer* from your tyre company contacts to give us a run down? That would be awesome. Perhaps a one on one interview posing the same scenarios and seeking his/her explanations?
Thanks once again Andrew , it was great to meet you in Melbourne , also I’m interested in a review about roof rack , rear wheel carrier and more about tyres ie fuel consumption ect
Good information. I like your work, Cheers
235/85-16 BFG KO2's on my 04 Jeep Grand Cherokee. Lifted it 3" and trimmed a little to get them to fit, they are noticeably better than the previous 265/70-16 I had on there.
Being from Minnesota, I concur with everything you said except you forgot to mention compound. A winter tire with a softer compound is the most important aspect of a winter tire.
Interesting discussion. I think you are leaving part of the tyre function on the vehicle. The tyre function is based on the weight of the vehicle in the terrain. Have you revealed the weight of the troopy, the standard kerb weight is 2385, GVM of the std troopy is 3300kg. The difference between something between a common vehicle like a HiLux or DMax compared to the way heavier Troopy would make a major difference of tyre functions. (HiLux 4x4 is kerb 1850kg and GVM up around 3000kg)
Live in Alaska I agree 100% with the snow tires,wide tires cause flotation zero grip and are a recipe for disaster but beach driving with a heavy load wide tires are a must
As for rocks, check out the Rubicon Trail, Moab Utah and all the good 'ol boy rock crawling down in Tennessee. Low pressure to increase contact patch, wide width to increase contact patch. More rubber on the surface = more traction.
Thanks for this input. Appreciated.
@@4xoverland I agree that wider tires are better on rock, particularly sandstone. Coming from a rock-crawling background in Moab, it's known that having more contact between rubber and rock results in better grip. It's worth taking a look at the wide tire widths used by competition rock crawler teams who take the technology very seriously to gain an edge. Cheers.
Some good info in the video. I too believe that each vehicle will have a "sweet spot" to do with its weight, stance, power, flex and materials used. Some much of engineering is trying to get your machine into that effecient sweet spot. Slapping large tires on, or boosting power is only changing one part of the cog so to speak. There will be a sweet spot regarding tire size that will match your vehicle. It may be different for each individual vehicle too. Once you find it it's best to stick with that. It will be good at somethings but let you down in other areas but that's what works best for your vehicle.
Changing even tread type has a dramatic effect on the vehicle as a whole as every part is working together or against each other.
The sweet spot will have fairly thin tires that can be for sure. That's why he mentions the arctic trucks having very tall tires to offset the width basically still making them a thin tire for the vehicle.
I've said this before and its worth saying again - You are correct regarding width for performance off road but its ignoring profile. a 9 inch wide tire will perform well but if its an 85 series sidewall you are going to lose lateral stability at high speed. Air pressure supports the weight of the vehicle vertically but the sidewall stiffness controls the lateral stability of the vehicle and the taller the tire the less there is. You can add more air but its the sidewall that's doing most the of the work, not the air. Meaning in an emergency situation a heavily loaded touring wagon is going to be less stable and more prone to loss of traction and control. Even in heavy cross winds at high speeds you can feel the difference. Where I live most of my touring is separated by long stretches of 80 mph freeway and while my 285/75r16 might not be the best tire in terms of width, they offer greater on road stability in those situations. The tradeoff is worth it to me.
Thanks Andrew. Best video on this topic that I have ever seen.
You make some very good points. In fact, it requires a very good motivation or special use situation to venture away from the sizes chosen by the manufacturer for the vehicle. It is not necessarily 'bigger is better'. In my own case with a 76 V8 wagon (265/65X16 standard) with all terrains and living in a farming area I was tempted to go to 285/75 X16 for some extra diff height without doing extra lift. Our local tyre supplier advised against it for all the reasons you discuss, but did advise me to rather change to 265/75 X16 when the first set was worn. The reason? They are the most common size 16 inch tyre available in the sticks here! The average farmer here pounds his usually overloaded 79 over rocks and potholes daily and they do not like wide tyres. So I fitted Dunlop ATR3 (3 ply sides) and managed an 8,000km trip around Namibia towing an off-road caravan without a single puncture or tyre loss. On the hard I ran them on spec pressures, whereas on hard gravel I went down to 2.3 Bar and 1.8 Bar nominally. If I even smelt sand I was 1.6 Bar all round. Why no lift? Besides not needing the extra height, it would require me to modify my garage entrance height. I think not.
Did you ever see one of the 15 million Model T Ford's on balloons?....and that was before there were proper roads.
Remember when he tested a black Jeep Rubicon at the United Arab Emirates in the soft sand and those tires were 12.5 inch wide well it never got stuck and it could roll right up those Hills nice and slow from a stop but skinny tires have to keep momentum to go through this and who cares about drag they're going to sink in if you have the power you're not worried about Dragon worried about floating over-the-top this is what I call a British overthinking
I drive 35" M/T for the past six years on many Desert Crossing on tracks like the French, Madigan etc but also quite a few remote Cross Country Desert crossings without tracks, not to mention plenty of beach driving on Fraser, Moreton, Stockton, Blacksmith and so on... I yet have to get stuck. Interestingly any Desert bicycle rider will choose the biggest fat tyres they can ride (on a bike that has it's limit as you only have one Man Power). In a car however it has little practical bearing as long as you have correct tyre pressures as nearly any modern car has enough power to push the little sand in front and the longer footprint and wider tyres compensate amply with plenty of traction even at low speed. On our last 3 Desert Cross Country trip the only vehicles not stuck where solid-axle LandCruisers with 35" wide M/T tyres. Have plenty of videos on my chancel which demonstrates that.
A narrow tyre is better for rock climbing? Hm I have yet to see you do any rock climbing or having a vehicle who could do this. I go technical driving once a week and that is 95% rock and wide tyres are certainly better as they give you a bigger contact area to latch on to. Wide tyres do no sit there and spin where narrow tyres don't if they have the correct pressure. Have yet to see a purpose build rock crawler in any competition on narrow tyres most guy's there do that for years and have tried every conceivable constellation.
AllOffroad 4x4 Adventures TV just search on RUclips “ stock Willies doing the Moab” and see
@@gabi.2.1 what do I see tough? Moab is a Rock Desert, can you drive it with Pizza Cutters? sure you can and for certain tracks and lines, some people use them but in general wider tyres better grip as long as the vehicle is set up for it.
@@gabi.2.1 my experience is a bit different from Andrews ruclips.net/video/snQdgMpAKfU/видео.html
I have owned 30 4x4s and have tried out many tyers and terrains.Currently i run a twin arb locked zd30 patrol on 7.50r16 Michelin XZL’s.The thing will go where you point your steering wheel.Also is impossible to get a flat tyer on them,even sharp river rocks can’t stop them.
Racing swamp buggies have tall narrow chevron pattern tires. Some UTV's mimic them. I went on a tag-along and watched a 60 series play in a swamp with 33" tires. It allowed him to move back and forth without sinking down and crossed it. 33's were the accepted norm. in this club.
This video arrived at just the correct time, because it's time for new tires and wheels for my Ford E250 Van, and i have been planning on getting BF Goodrich AT's. But two different sizes are available for my vehicle, one is wide and low profile and the other narrow and taller... thank you.
As a KO2 owner I say find something else...they've never gotten me stuck but they are just alright everywhere, except wet road in which case they are scary.
T4nkc0mm4nd3r I'm used to them being like that. I have had two other sets on some other vehicles.
I've been a little concerned about having to go to a narrower, slightly taller tire in order to fit all terrain tires to my stock 16" rims, AT's aren't made in my stock tire width, and this eases my mind considerably.
I'm glad you've been able to convince yourself that narrow is better than wide. I've been struggling with it for decades. The big difference between us is that I don't deflate my tires off-road. I guess I'm just too lazy. I've experimented with 235-85 17 on a full-size pickup vs 265 75 and on my FJ Cruiser I tried 255-75 vs 265-70. I never do any sand driving anymore. But we have our winters with lots of snow and ice. I still think the wider gives you better response with handling braking and acceleration just about everywhere at full tire pressure. I think the narrow tire will loose traction more quickly when rolling over smaller rock because it acts as bearings and lifts most of the tread off the ground where the wider tire will confort a little better and retain more traction (at normal pressures). The pickup with narrow tires would spin more readily on just about any surface. Of course my opinion is still a guess because of the advancements in compounds over the years but I went through 5 sets of tires with the pickup and 3 on the Cruiser probably another 4 on a Ranger. I never deflated on dirt because my speeds were often too high. On ice and snow I also kept normal pressures because I wanted the studs to work efficiently which they do. SO... in the end I tend to go on the wide (stock) size purely for the extra traction in emergency situations in every day driving. Modern vehicles with all the safety electronic nannies are calibrated towards stock size tires and I don't want to risk loosing their effectiveness through tire widths.
Thought that would be your view and i agree. But how did you find the noise coming up from Melbourne to Ipswich i didn't get to ask you at the Ipswich meet and greet the sponsor seamed too be taking up your time, it was good to see you and your daughter there.
Very informative! I'll consider narrower tires next time I need new ones for sure.
Hey mate, awesome video once again. What size are the tyres you're currently running?
Got a 100 series Cruiser, stock tyre is 275/70r16 (31.16"). Lots of guys go up to 285/75r16 (32.83") but I'm thinking of going 265/75r16 (31.65"). Opinions? Should I try stick with the stock size? Noting that there are less tyre options at the stock size.
Appreciate the video Andrew! What’s your opinion on 15” wheels? I would assume, if you can fit them, they would be better than 16” or 17”.
If you can fit 15" wheels, you have brakes of no use. :-)I run 15" alloys on my old Vanagon 4WD, orignally wanted to use 215/75 R15 but because of weak brakes I sacrificed some clearance and went for 205/70R15.And then guys, try to beat my narrow tyres! :-D
Fully aligned! Also prefer narrow, especially for sand! Runed 235/85 on a kzj95 in sand and it performed great!.now running 255/85 R16 on a Y61 lwb and also expected to perform great. The only downside is road handling, but you get a better fuel milage! Great review!
Maybe week or engines and lighter vehicles are better with narrow in the sand because he tested that black Jeep Rubicon in the sand and those tires were 12.5 inches wide on the dunes and it could literally stop at the bottom and go up huge hills without sinking because of the flotation of a wider Tire. I have tested skinny and wider in the Sugar Sand we have here in the desert of Arizona that is extremely loose thick grain and hard to walk on it doesn't pack the way Dune sand does when you push on it it is completely loose and my 285 75 16 perform much better than skinny tires that just sink in. That's why dirt bikes and ATVs have pretty wide tires for how dramatically like they are under 300 pounds. The whole drag Theory makes no sense unless you're driving some old Toyota or Old Land Rover with no power but all the most powerful newer vehicles with wider tires float right over sand like nothing they don't have to keep momentum to keep going that literally proves it's better.
I am running 285/70/17 Cooper STT PRO’s on my FJ Cruiser. On a 3 inch lift.
My rig takes me anywhere I want to go.
I aired down one snowy night ,2 inches, and it did offer better traction. I have always thought skinny tires were good for snow. Did that larger contact patch help me out that night?
The narrow front tyre on a tractor has one feature that you do not mention. They usually have three straight groves that are aligned with the direction of the tire. The object of the three ridges is to direct the dirt or mud into the areas between them and that allows them to float above the muck and still have the sharp edges contacting the main strata so that they can turn with ease.
I've noticed in muddy condition, a skinny tire might be beneficial as it cuts through the soft mud and reaches the bedrock underneath to give better traction, rather than float on top and getting packed with mud.
Agree, I put 235/85 16 on my Pajero ( second Gen) instead of the original 265/70 15. Much better in every Offroad Situation, but on Tarmac the skinnys sucks a bit. Great Vid.
Another great video Andrew.
I think a good part of the tyre selection problem is advertising hype .. ie. wide tyres are the current 'fad'.
They look good because everybody else says they look good ... just like when you go to by a 4x4 .. everyone wants a Toyota.
Everyone wants a Toyota because everyone else tells them that they need to get a Toyota ... without 'really' knowing what they're talking about.
Don't get me wrong ... vehicles like Landcruisers are very capable 4x4's .. they're just not necessarily 'the' 4x4.
When you buy a new LC the first thing that people do is get rid of the factory wheels and put 'huge' tyres on them because that somehow makes them much more 'capable' and 'macho'.
Due to a lack of knowledge .. and experience .. many people purchase every accessory they can get their hands on because that's what you 'need' to have a good 4x4. You only need to look at the range of accessories that are in the 4x4 stores now .. along with the ridiculously high prices. And people just pay it!!
Another great video and explanation! How is your trip across Australia going so far? When can we expect the full review of the KM3?
Most off road tires today at a 33 to 35 inch tire range have a 12.5 inch cross section. Years ago you could get those same tires in a 10.5 inch cross section.
IamTranslation Preach! Super pissed they don't make 33x9.50's anymore. :(.
jeep6242 , interco still makes them.
IamTranslation , My Cooper ATPs are sold as 285.75.16 and measures out to 32.8 x 11.50. They seem like a good all around tire for my 3/4 ton Suburban.
Old Griz Yeah but the rubber compound on intercos is from the stone ages lol. You couldn't pay me to drive those tires on wet pavement, snow, the highway lol.
Old Griz Yeah I think for vehicles that big you start getting close to the level of diminishing returns for super skinny.
Getting myself a set of Skinnies in 255/85 /16's for 02' Tundra.
-Great discussion..
They way I think of tires is in biting edges. How many biting edges do you need for the terrain? A major factor as well is vehicle weight. The other factor is how much force will your terrain support per inch
Can you tell BFG to bring skinny tires the the U.S.A. ? Please!
really interesting ... I drive a defender , and im looking for new tyres ? 235 or 265 ... what would you pick , Great vids ...
235/85/16 KO2s on my TRD Tacoma, stock 3:73 gears.
Thank you, as always.
Key to this whole lecture @8:28.
I like tall-skinnies on light vehicles with low power (Zook)
Vehicles with higher power (Steering, Brakes, Engine) I like a wider tire.
I can deal with as large of a rim as a 20" as long as the tire is a 37" or larger.
17s are the norm for most here in the states anymore with the size of the brakes that come stock. For a 17" the lowest diameter I like is a 33" tire on an off-road vehicle. On the STT Pro I like the 12.50 over the 13.50.
I went from 255 mud tires to 305 and they were terrible. Always floating through corners in the mud and just squirming about where my 255's just cut through and drove like it was on rails in comparison. The 285's I had next were a good size as well, but taller than average as they were 285/75r18 and on a very heavy truck. Despite being an uncommon size in North America I"m back to 255/85r16 but I have yet to get off road much with this tire yet.
Look at the aggression on his face when he is getting in to it lol
I am in agreement with you Andrew. I have spent many years in the military driving just about every kind of vehicle you can imagine from small 4x4s, medium and large 6x6 trucks, tank transporters and amphibians in every environment. People just need to look at the tyres that the military use on their vehicles and realise that millions of miles have gone in to testing tyres they use for the best and worst of conditions. I can tell you that nearly all of the tyres are of the taller sidewall thinner profile and mostly with an all terrain tread pattern type. Go look at what the military use and make it an easy decision.
About the rocks(rock crawling) while you are correct to a point. However in America where they build rock crawlers all day long with wide 40 inch tyres and wide axles and narrow bodies. They do it for it stability.
What they do, where they get to and the obstacles they do you're not going to get a Overlander type 4x4 on skinny tyres near these these things.
It's apples and oranges.
I run a wider tyre and I prefer it for rocks and feel like I have more grip.
I agree. My Jeep JKUR climbed steep loose shale better with the stock narrow 32" BFG Mud Tires than with the wider 35" Mickey Thompson MTs.
it would be nice to know how far you let the pressure down on a rim, i suppose that heavy trucks could be in trouble at very low pressure, bead lock rims are commonly used in the US, are them really better?
My truck is quite heavy and running 17" rims i'm worried about let the pressure too low especially during sharp turn while offroad, so the only way out for me is to go wider tires, what do you think about?
So, it is mostly about the percentage of a tire's radius that falls below the tracks surface. As that percentage increases, the rolling resistance increases as well, until it meets up with the tractive force, leaving you stuck. Also, in certain circumstances, the greater the percentage of radius that the tire has sunk to, the more power it will take to pull the trailing side of the tire up out of the material it is buried in, which will also result in some downforce on the tire. It certainly does no good to have the leading, and trailing sides of the tire fighting against each other. In certain circumstances, wider tires will make this problem worse. However, increasing the diameter of a tire means that for a given depth you have sunk, the percentage of radius below the surface will be lower.
Andrew, thanks for this video. I am looking at buying a new set of tyre for my LC79 DC. I have narrowed the choices down to BF Goodrich AT KO2 265/70R16 and the 235/85R16. The height of the sidewalls are 265/70 is 185,5 vs the 235/85 is 199,75. I selected these tyres because both are 10 ply tyres which should help me against punctures in the Tankwa. I understand that the ride comfort is going to suffer. My concern is that I also do lots of Namibia dunes so I need good performance in sand. I am leaning towards the 235/85 because of the higher profile which I believe is going to give me a longer footprint at low pressures. What is your opinion?
When are you coming again to the US Andrew?
Thank you. Really enjoying the explanation of so called 'simple' overlanding topics. It's comforting to have an expert opinion you can trust. Looking forward to more.
If my load per tire was 1000 pounds and my tire max pressure is 50psi at 2000 pounds. Does that mean I should always run between 25 and 50psi? Would it be ok to run less than 25psi at slow speed off road?
Actually changed my tires because of your recommendation .. and I had a major problem: I have a 2001 Ford Explorer 2Dr Sport and I have run two sets of BFG KO2's in 285/75 16" getting over 40K miles on each set. I decided to try the BFG KM3's in 255/85 16" .. They seemed to work well but coming back from a recent road trip something wasn't right .. took it to my mechanic and decided to rotate and rebalance the KM3's .. well, they couldn't be balanced! 7052 miles and the tires are junk! At Jack Furrier Tire here in Tucson they tried to rebalance them with no luck .. there was a definite 'hump' in each tire as it spun .. like the tire was hitting a bump? I never even got a chance to air them down. Put on a new set of BFG KO2's like before .. problem solved. I sent a email to BFG .. we'll see what they say.
Have you heard back from manufacturer yet? Just wondering if it was a defect or the design is flawed? Thanks in advance.
@@boblafountaine9560 Yup! There is no warranty on the KM3's .. none, as they pointed out. They weren't really interested in why they failed.
Tyre technology might have changed with improved materials and modelling techniques but the traction and offroad formulae for different types of terrain is still based on the formulae developed in WW2 with just a few tweaks in the 50s-70s... you've got mechanical engagement, friction and rolling resistance all balancing off each other and all affected by many variables.
How's the fuel milage with the new tires compared to the old ones?
Narrow will win all the time
I wanna see a guide video from this man on long distance tarmac driving on stock vehicles. Helpful tips on accessories or things to keep in the vehicle to make driving easier without turning the while vehicle into an overland tourer.
I agree partially with what you say but too many variables. I agree Pressure on a narrow tyre may be more but friction increases with more rubber on the surface. A wide tyre on rocks also helps straddle rocks where a narrow one might get caught in a crevice or slide off more easily . Also width of the rim impacts on drivability as a narrow rim on same sized tyre hold the tyre better than a wider one imo.. finally at very low tyre pressures, we talking 8-12 can increase width of contact as well as foot print length..
Real good video and thanks for your opinion.
So Andrew what are your thoughts with regard to the commonly available tyre sizes for 4x4's at the moment? It seems to me there's a distinct lack of tall but narrow options! I'm a fellow troopy owner and I've always enjoyed and seen the benefits in narrow tyres but if you want to go slightly taller you have to go a lot wider and the few exceptions available are only in certain tread patterns (for example BFG makes a 255/85r16 but only in a mud tread not all terrain)....
true about the old tractors ... but the new tractors in USA have very wide tires , I mean gigantic wide tires ... front and back ... why ? I wonder if they went with narrow tires in the old days because the rubber was more expensive and also the manufacturing process ... possible maybe ?
Andrew, looks like a fairly wide tyre in the background? what size is it?
Amazing video. I couldn’t agree more!!
I’m going to get some BF Goodrich’s for my 76series.
Do you normally run All terrains or mud terrains on your troopy?