not really. Using Silca's tyre pressure calculator for the past 2 years. Mind you, not tubeless, for its notoriety and fussiness due to the sealant, but with TPU.
Just switched to TPU tubes on my gravel bike and checked on the silca calculator after getting a pinch flat what pressure I should be using. Turned out I'd been running at 50psi and they recommended just under 40 for my system weight and tyre width. Much comfier ride now too.
I've regular Conti 5000 25C with tubes and forgetting to pump them up to spec more often than not gets me snake bite punctures. So pumping up tires before rides is obligatory.
Because I'm lazy and ride on a variety of surfaces, I tend to inflate to a little bit higher pressure and then wait until they're noticeably lower before re inflating
No! :-) and you are overcomplicating the issue. Assuming a not rigid tire, contact patch is proportional to pressure. - No matter if the tire is 25 or 35 mm vide(!). Its as simple as Contact patch area(m2) = weight (N) / Pressure (Pa). 60kg = 588.6N, 6 bar = 600,000 pascal. 588.6/600.000 = 0.000981m2 = 982 mm2
You might be right about the elephant/stiletto thing because I have seen signs saying 'NO STILETTO'S' but I've never seen a sign saying 'NO ELEPHANT'S'.
“I love you, bye!” Ollie is one of the greatest presenters on RUclips and we are lucky that he presents cycling content for us all. Always interesting, well presented and explained, with just the right amount of humour/humor to make it enjoyable too. GCN, hang on to this gem of a man!
Same as me , I use 23 and 25c , have one bike with 28c tyres , rides awful and refuses to bank down in corners , they are awful to corner on , 23 and 25 handle 10 times better , no wonder so many crashed in the Tour de France using 32 car tyres the bloody retards , modern cyclists are being sold a load of overpriced rubbish ...Not had a puncture since 2004 when I rang the wife to come and pick me up 40 miles away , Conti Gatorskin since they came out , all my bikes have them on !
Some of my fellow club riders don't watch the road and have crashed after hitting easy to see pot holes, when driving or cycling I keep me eyes and focus on the road.
I experience far fewer punctures since reducing my tyre pressure. I believe a lower pressure allows the tyre to deform around sharp debris instead of being penetrated by it. It's much harder to prick a soft balloon than a fully inflated one.
On 28mm tyres I got 4 punctures in 5000km. Now I use 32mm tyres, 4500km and only one pucture so far. So, let's hope the next 500km won't be a puncture fest.
During about 3,000 km with new 23mm road tires I had about 11 flats. 10 of them on the front tire, and one on the rear tire. I now have 25 or 26mm road tires, and they're a tight fit. No flats but only a few hundred km.
Riding somewhere that trashy tourists leave broken glass in the bike lane doesn't help my chances. Lucky so far - one flat on the commuter bike in 1.5yrs (glass shard in a 35mm tire) and none yet on the road bike. With the junk tossed in my space I am not optimistic for maintaining no punctures on my road tires ;(
Have 26mm front, 28mm back. 1 flat (front) in 3500km. So far so good 😅i must admit 3500km is for the outer tyre, the inner is way older than that, probably closer to 6000km or more. Netherlands has good cyclepaths.
I'm an old fashioned rider, with 27 inch rims on my road and tandem bikes. I've been running 1 and 1/8" tires for years and can count the flats that I've had in the last ten year on one hand. High pressure, up to 105 lbs per square inch on my old Avocet Model 30 Road tires. Now I'm running Panaracer Protite's, 1 and 1/8" and I've still never had a problem. Narrow tires at high pressure have less rolling resistance. Where I ride, here in Ohio, the roads are pretty smooth. I can see wider tires on crappy roads, giving you more flat protection, but on decent roads, I'll take the narrow, high pressure tires, any time.
This is super interesting! Several points genuinely surprised me, and they will undoubtedly influence my future decisions regarding tire pressure and choice of tire. I love when scientific research leads to development on new knowledge like this.
I’ve been setting pressure in the tires of mine and wife’s bikes at 15% drop for about a decade. I initially tried this based upon somehow finally fully comprehending a magazine article from the 1970s. Although all 4 of our tires are identical I have a unique pressure in each tire because of difference in F to R weight distribution and difference in her weight and mine. The 15% drop came from lab test study on drums for optimal rolling resistance. I can’t confirm the speed but do perceive it to be true. I can attest to other benefits. The most noticeable is better handling because this results in F and R tires having same size contact patch. Tires last longer because the intended width of tread is used, spreading the load and not concentrating wear along the center of tread. The GCN observation about fewer flats has no argument from me. I’ve encountered this in aviation, manufacturing, and cycling, prior generations understood something, subsequent generations lost the knowledge, and sometimes we rediscover it.
Ollie and GCN, What about the energy loss due to compression of the air in the tyre and energy loss due to the deformation of the rubber? Compressing gas requires oodles of energy that is lost to heat (thanks for nothing thermodynamics!). Cycling 20 years ago we could ignore deformation as we all rode skinny tires at very high pressures. Today I see road bikes with 30mm and even 35mm tires at ridiculously low pressures and you can clearly see their huge contact point and deformation with the naked eye. Its no longer a negligible variable. As an engineer I'd love to see some models showing energy losses due to Crr vs. Compression/Deformation energy losses vs. Aerodynamic losses (0deg yaw) vs. tire pressure (bar) and load on tire (kg).
Hysteresis loss is smaller with bigger tyres/lower pressures. You may find this discussion with Josh Poertner of Silca interesting. ruclips.net/video/ZuxUWFziuGI/видео.html
The majority of the air compression happens when you get on the bike, so only once. As the tyre rolls the pressure will be constant (aside from the effect of bumps obviously) so I don’t think that’s a concern. On the deformation I think the argument is that the wider tyre gives a wider rather than longer contact patch which reduces much of the hysteresis loss you might expect if the contact patch shape remained the same.
@@robertpoll27 sounds like you have never ridden a bike outdoors. The whole point of a pneumatic tyre is to give suspension to the rider, because the 'effect of bumps' is happening *all* the time. Evenon supposedly smooth surfaces. The rider is also moving on bike via pedalling, when sprinting, standing up for hills and also off saddle when it surfaces get rougher. It's a constantly changing dynamic system which means the tyres are constantly deforming. How well the tyres deform is key to a bike's comfort, handling and efficiency.
The compression/Deformation energy losses that you are concerned about are included in the measured rolling resistance. And the one factor that you have neglected is road roughness. High pressure narrow tires have the lowest rolling resistance on ideally smooth indoor wooden velodromes, but as you move outside onto real roads, the degree of roughness impacts rolling resistance. The ideal tire matches width and pressure with the roughness of the surface. As the road gets chunkier, wider tires at lower pressures are faster.
I have suffered so many punctures on my 50k commute on Auckland city roads on a 55kph ebike. Most have been a "snake-bite" pinch punctures from manholes and potholes (in traffic they are sometime impossible to avoid). My carbon wheels do not allow tubeless and I am running 32mm Continental GP5000. My final solution is very involved. 1. Very think inner-tubes. 2. A "ghetto liner" (where you take an old inner tube, cut it along the inner circumference, and then place it inside your tire over a new inner tube) 3. Tyre Slime 4. A high tyre pressure, about 85psi. Finally I seem to be running puncture free.
I’ve been going up on tyre size and down on pressure every few years. This morning I realised I know ride exactly at half the pressure I did 12 years ago and have moved from 23 to 30s. And I do love the way the 30s feel, both comfy and fast
@@Fudgeis1337 Sometimes the note shows 'out of stock,' but it refers to a specific size and colour, which means the product is available in other sizes and/or colours
Hi, thanks for the video. I once learned that the grip over pressure in NOT linear for rubber. This means there should be a optimal (contact patch) pressure for a given compound. If I understood correctly this has something to do with the rubber interlocking with the surface, but at a certain pleasure the interlocking is complete and an increase in pressure does only slightly increase the grip. I guess we should strive to hit this sweet spot. Or tire manufacturers should strive to provide tires that hit that sweet spot when used at correct pressure. (just to make it bit more nerdy ;-) )
You should do more videos like this with useful data. 30/32mm wide gp5000 tires, at proper pressure, with silca sealant will make it very hard to flat. I havent flatted in a couple of years now, about 12000km and im 90kg. Using proper tire pressure and a good selant that is kept up to date is key. I hope Pirelli keep improving thier compound to catch up with GP5000. And I believe Tadej ran gp5000 28mm TT TR last year, this year he went to 30mm gp5000 S TR. And he can basically pick any wheel/tire combo he wants, so this speaks volume to that tire.
Thanks for this! Here's a case where English units are intuitively more helpful than metric. A 180 lb bike HAS to support 180 pounds. If it's distributed over 2 square inches, that means 90 pounds per square inch. (I'm a little skeptical about the statement (8:00) that there's more pressure in the center of the contact patch. Granted, central tread wears faster, but that's the area that strikes the ground most frequently. Gasses in a closed system press everywhere equally; that's kind of the point.)
maybe it has to do with the molded shape of bike tires vs. car tires? if they're measuring the actual pressure of the contact patch, I'd expect there to be variation from the center line out, since the tire isn't flat across its surface.
@@johnhufnagel I think they mentioned that the physics of car tires was very different than bikes. A model of the gas dynamics of the contact patch might be a row of gas cylinders joined at the top. The force on each cylinder will be equal, no matter whether some cylinders are pressed in more than others.
I ride with 23, 25, 28 and 32mm, and so far, i prefer 25mm. I don't feel much difference with 23/25 and 28/32 are way more sluggish when going out the saddle. The biggest factor isn't tyre width but tyre compound and the innertube. Switching from butyl to latex/TPU or even tubeless makes a big difference. And from experience riding daily with them, 28mm Hutchison sector are slippery as hell on the wet whereas 24mm cinturato are as good as on the wet as on the dry.
Silca's tyre pressure calculator actually gives me some 5 to 10 PSI higher pressure recommendations than those given by the SRAM one. I like the latter more; I feel like the recommendations by Silca are overly high, leading to a bumpier and slower ride. (With 28 mm tyres and interal rim width being 21 mm.)
Doesn’t it depend on the surface you select? I find the pressure from ‘new pavement’ to be firmer than I like. I use ‘chipseal’ now and find it feels good on nicely paved areas and soaks up bumps in the poor areas.
Well done, GCN! In the late 90’s and early 00’s, I was convinced that carbon fiber technology would revolutionize cycling, and it did. What has surprised me in the years since, is how much greater the effects that improvements in brake and tire technologies have had on our sport. On our rural west Texas mountain roads, I find that my 25lb(11.5Kg) steel-framed, early “gravel” bike is just as fast on 32mm tires as my 19lb(8.5Kg), mid-level carbon fiber Cannodale Synapse is on 28mm tires. Both bikes have the same gear ranges, both have low spoke-count aero wheels, and both are running the same brand tires of the same spec. I’d put 32’s on the Cannondale, but they’re too big to clear the fork crown. Sigh.😁
Late 90s was when VREDESTEIN touted their high 175psi clinchers. In my local group ride nobody was crazy enough to go higher than 120. I still have several NOS Fortezza clinchers and still think that VREDS had superior tires. But only 23mm for my Colnago Master with Mavic Open pro wheels still running true.
@@andreemurray7039been using Paves since the late eighties...never went back to 23s . I'm a bit large so 27/28 worked out well. Still riding the rims from that Era. Wide and flat ...those have a noticeable positive impact on ride feel too....not areo though. Vitoria Special Pave was my favorite. The cool thing with the latex tubes in them is you can air them up and by the end of the day they do have a little less pressure in them oh and they make themselves anonymous while riding and ward off a few puntures along the way 😊
As someone who has ridden in many different states, where you ride and the condition of the roads plays a huge factor in tire choice. Southern Europe and the Western US have Puncturevine (goat head thorns) that I've seen puncture many tires easier than metal/glass.
I still use 25mm tyres, but get far fewer punctures than I used to. I'd put this down to: 1. better tyres with some puncture protection 2. better pump to stop pinch flats 3. lower mileage 😞
@fredmcgough748 Going faster produces more vibrations that are felt by the rider. But more vibrations (from higher pressures) does not mean you are going faster. "Feels fast" is a highly misleading sensation.
@@fredmcgough748 All of the data suggests that running 28's or even 30's will be faster on public roads....if you ride on perfect pavement, or a velodrome then skinny is better....but for 99% of riders wider tires will result in faster riding.
Sorry I understand most of the content and am enjoying using wider tyres thanks to GCN. But I'm confused by the contract patch sizes and units used at 6 minutes. I'd imagine perhaps around 100 square mm (1 square cm) rather than 1000 mm squared.
The other huge area of difference between performance automobile tires and those on bikes is heat, which is a total non-issue with bikes, but a core constraint with any car tire, and likely the most significant factor in designing racing car tires.
25mm will go the way rim brakes have. Running on 28 and 35 on my road and gravel for commuting... 1 pinch flat over 20k km (and it was me being too fast for my back wheel on a curb climb...) Pirelli Race TLR and GP5000 STR. I think the Pirellis are slightly more resistant to wear but still early to tell. Tubeless with Vittoria airliners in for added protection.
Appreciate you addressing sponsorship. It makes you more trustworthy to us viewers when we know there's sponsorship involved. Also, elephants have feet, not hooves!
As a voice from the past, I have some comments . When narrow(25mm) clinchers first came out in the mid 1970s, I put my sew ups aside. I got more flats on the clinchers. I deducted unscientifically that the clincher rim was stiffer and worked like an anvil above the tire. Kind of like putting the tire between a rock and a hard place. As a dark horse in my cycling club, I returned to sew ups. I could wear a tire out and could almost predict the day it would puncture based on wear and road conditions. Fifty years later I still ride cheap sew ups and am happy. Any cycling archeologist can tell you that back then ,for Paris-Roubaix there were large cross section ,very light silk tubular tires. So your contact patch science was considered back then. Moral of the story? I think experience and the willingness to understand are important. Off road guys know how to receive the variations in the ground surface. Roadies should do this also. I call it riding vertically while going along. This is difficult in a pack , but can be done by choosing positions within the group. I never lost a race due to a problem with my bike. I lost hundreds of races due to the other guy(s) being faster or using better tactics.
I am tall and well built => heavier than most cyclists I thought to run at higher pressures to compensate ie at 7 bar. I was made aware of the SRAM and Silca tire pressure and found I should drop my tire pressures by 1 bar. Amazing big difference in ride comfort. I still partially to sligh higher pressure to avoid punctures from the many potholes, but ti seems even dropping the pressure a little can make a big difference in ride comfort
Just had my first proper flat that the tubeless sealant couldn’t self heal this weekend. Been running 28mm tubeless for nearly two years, so while it could be a coincidence I’m inclined to believe the science here.
Cool video. I switched to tubeless 28mm back when Schwalbe came out with the tubeless pro ones (2015ish) and never looked back. My initial reason for switch was to cut down on flats, who knew there was so many more reason to switch. I've also mastered the art of tubeless setup by making every mistake possible :)
Been a year since my last puncture on road bike. I don't stress when I get one as it's easy to fix with my rim brake bike, tyre can be removed and fitted by hand, got C02 and a decent pump. Prefer 25mm tyres with TPU tubes normally, have run 28 and 32 in the past.
Sorry Olly, pretty sure Pogačar rode 30mm tyres in this year's Tour? Not 28mm. I started riding 30mm this year, the best comfort/grip/speed I've ever had. On my C64 the ride is simply sublime. At 82kg I use 70psi (4½ bar). And when I think back, I used to race with 23mm Tubs, 110psi, back in the 80s 😳
@@seanmccuen6970 Well seeing as that Pogaćar's tyres measured at nearly 33mm, no 32mm tyres are not needlessly large. I stopped using my 28mm road tyres many years back after realising my 33mm CX tyres were just as fast and way more comfy.
@@JeremyLawrence-imajez nah, 30's mounted on 25mm internal width rims were apparently his go-to package, thus the '32mm' measurement (your words). he wouldn't run 32's which are overkill for normal pure road riding, he wouldn't accept the WEIGHT penalty (nor the less than aerodynamically optimal tire cross sectional shape). only time 32's are 'optimal' on a road bike is if it's wet and filthy out and/or you prioritize increased comfort over anything else.
@@seanmccuen6970 Sigh! the width of a tyre is what the ruler/calipers measure it at. Size labels on tyres are as notoriously inaccurate just like clothing/shoe sizes and they can only be accurately stated in conjunction with the rim it is fitted to. Pogaćar rode tyres that measured at nearly 33mm, ergo he was riding 33mm tyres. Not to mention that a wider rim will also be heavier than a narrower one and that weights of wheels have gone up of late anyway because the benefits of non ultra light wheels make up for the extra grams. People not that long back said 28mm tyres were too wide, heavy etc just as you are now saying about 32mm tyres. Plus ça change.
@@JeremyLawrence-imajez lol nah, measured tire size is a product of the tire size and internal rim width (btw, I get actual tire sizes can vary re. manufacturing, etc). he was running the overall A-1 optimal tire size of 30c for 'conventional' road riding/racing on insanely wide modern wheels which equated to around that measured 33mm figure you stated. he was running 30's, no less, and definitely no more (per my original point).
My 28s are inflated to 90psi. Anything lower than 80-85psi feels like a flat to me. Finally used up the 23s I had, felt like a hard rubber tires at 85-90psi. My son prefers 23s, wear as I have switched to 28s, on my old Mavic rims. I ride to & from work, 22 miles round trip, and for exercise on weekends. Paved streets, not going fast so I can't avoid road hazards. Never had a flat on the road/bike path or on the Coney Island boardwalk which is why I still use tubes, however have had ONE flat sitting in the garage (aged tube), I own 3 bikes.
I have been using extra thick or thorn resistant tubes since the 90's. They are much heavier than a regular tube but I hardly ever get flats. The hand full of times I have gotten flats I was not riding on the rim making it much easier to stop. My .02
The current focus on low rolling resistance with tubeless tires is the main cause for more punctures. There is less tread and casing material compared to equivalent clinchers. Wear and durability is half what it used to be. At least sealant gets me home with small punctures.
In 50 years of active cycling I’ve found the greatest contributor to flats is riding over debris and having it “pound” into the tread. You pick up the bit and every rotation it’s driven up into the tube. Back in the 225g tubular days we would see the debris and use our hands to brush the debris off before it could puncture. Also damp roads are doubly problematic. The water acts as an adhesive to pick up debris and a lubricant to drive it through the rubber. Over 300,000km I’ve replaced more tubes from rotting than puncturing.
On my all purpose bike (commuting groceries and touring I have 50mm tires, semi slicks never puncture and rolling resistance is rather low when pumped to near 4 bar. The reccommended pressure is between 2.0 and 4.0 bar, when the roads are bad I can lower the pressure for more comfort. In winter I mostly ride on the "dual fighter with a smooth rolling patch and more grippy profile. The nice thing about wide tires is that you have a lot of freedom adjusting pressure to circumstances. Cheap tires suck because when adjusting pressure for gravel or snow the rolling resistance goes through the roof!
@@michab4083 Off course there is. Off course there are also other factors to take into consideration. Factors that outweigh the advantage of lower rolling resistance and therefore make riders choose wider tyres. Like lesser chance for punctures and the potential associated loss of time outweighs the win in time because of the lesser rolling resistance. The choice of wider tyres is by no means proof of a lesser rolling resistance. Why do you think sports cars need wider tyres? Exactly: for more grip (or ground resistance)
@@michab4083 One thing seems for sure. If you are a 55-65kg pro, riding pro speeds, those 28mm tires most of them use must be fastest. Couldn't imagine otherwise. The situation for mere recreational riders might be very different. I personally find those wider tires more pleasant to ride on, and if folks pass me because they are fitter or have faster gear, good for them.
No discussion about the type of tube and its effect on the tire patch. There must be a difference between butyl tubes and TPU tubes, and I bet the difference is that the TPU tube has less rolling resistance. I heard somewhere where a TPU tubed tire runs with almost the same resistance as a tubeless tire. So the TPU'd tire will be lighter (no sealant), almost as fast as tubeless, and none of the mess and hassle of tubeless. I've been running TPUs on both my road and gravel bike for over a year now, and love 'em. Give it try if you're considering it. TPUs are expensive, though, but easier to patch than butyl.
contact patch area = gross weight / tyre pressure. If the tyre has carcass strength then ground pressure can vary across the patch and the patch will be smaller.
I’m not sure about the effect on punctures, but I just learned the lesson of wider tires at lower pressure and the ride now never felt better in my life. I was riding 25mm tires at 120psi! I’m 200lbs so my rims and tires hated me. 😂 After a spoke break and splitting side walls, my local shop recommended 28mm at 90psi or lower.
I was baffled when my colleague that shares my commute route had WAY less punctures on his 25mm tires compared to my 35mm gravel tires. The reason we found out was shells from acorns and other nuts, they "skid" off of his tires but get stuck in the more aggressive profiling of my tires. Then again I run tubeless and just keep on cycling and he needs to change his innertubes :D
I got one puncture in four years / about 40k km's, and I ride the shittiest b-roads, forest roads and rocky gravel. Proper pressure, considerate line choice, wide(r) tires and running mostly tubeless prevent a lot of headache.
I recently changed from Maxxis to Pirelli.... OMG... It was like I found god.... I am doing 3 to 4km/h faster and the bike now feels sexy on the road... Love them love them love them.
I run tubeless and haven’t had a flat in several years. The last one was a long sliver of steel that cut a slit the tire.BTW I ride gravel, road, and a bit of trail/mountain bike.
Ollie..I thought that was super interesting and you did an excellent job explaining the science in understandable terms. Also, that blue sweatshirt is your color man
Good, useful content Ollie: thanks. (Notice my lack of snark, for once? Wonders will never cease.) I like Pirelli tyres. They last pretty well, roll pretty fast, and are ever so slightly less expensive than Continental. One of their gems is the vanilla P Zero - not the 'Race' model. £10-20 cheaper than the 'Race' (let alone the RS) model, with about 90% of the performance (slightly less grippy tread, I think). A little bit hard to find: I think they/importers/retailers know these are a good value (read: lower profit margin) tyre. For those of us who go through tyres like underwear, this is an advantage: keep the gee-whiz £££ tyres for Sunday best, put some almost as good lookalikes on for trucking around on during the week (or for superannuated hacks like me, use them all the time) and let people think you're running £100 tyres ALL THE TIME and make it look as tho you're rich or sponsored (hah!) or summat lahk tha'.
Pinch flats were mentioned, but there's another factor as well. Given a fixed size defect in the road surface, say a 1/2" rock, the danger of totally compressing the tire is much greater for that 18mm tire than a 28mm one.
I believe you stated the question incorrectly at the start: 'which vehicle puts more *force* at the bottom of its tires?' The force is the total load, not just the pressure. A tire with a 100lbs load will put 100lbs of force into the ground, but the smaller ther tire, the higher the pressure.
I actually genuinely can’t remember the last time I got a puncture on the road, it’s at least a couple of years ago, probably at least 12,000-15,000 miles since I had a puncture in road riding, and I use race tyres year round on crappy British lanes full of debris and pot holes. Running tubeless tyres between 25 and 32mm across multiple bikes, at modern low pressures as recommended by the SRAM calculator. I did have a sidewall puncture a few weeks ago - but that was doing a rough gravel descent at speed on road tyres, so can’t really count that! I put a plug in the tyre and then did another 500 miles to complete the ultra race I was doing without problem.
Just stared last year. No punctures in 5000km. Riding in the lane; not on the debris-filled shoulder, (as much as safely possible). 28mm & 30mm @5ish bar
I’m still using 23mm tire because Zipp says that they make my 2011 808 Firecrest wheelset more aero. If I go bigger the rims are less aero. I would need to buy new wheels to run wider tires.
Ollie - you is a scientist mate! Pressure is Force / Area, so the tyre pressure and the system weight almost totally determine the total patch area. For example, my system weight is roughly 155 lb + 20 lb = 175 lb. Let’s call it 180 lb for fun with full water bottles. Now if I have 90 psi in each tyre (of course I do not I read the Silca pressure calculator too!) and equal weight distribution then each tyre bears 90 lb with 90 lb / sq-inch so the total area of the contact patch on each tyre must be 1 square inch. Of course the SHAPE of the patch must vary (wider tyre = wider side to side and narrower front to back) and the properties of the casing will have some effect to the extent that tensile forces distribute some of the load (so the actual patch area in contact with the surface will be marginally smaller than 1 sq in). I assume that the tensile redistribution is small, but if later in the video you reveal this is wrong that will actually blow my mind (that would be like those nifty string spokes Pidcock and Ferrand-Prevot rode to glory…).
i saw the video and have no idea why my bike tyres get more punctures but i should choose pirelli because they think about it aside from that i think its tyre (training tyres can be slower but more durable), roads you ride and your attention to obstacles that can puncture you
@oli don't forget to mention for a non-skidding tyre, the contact patch is stationary and the the opposite side of the wheel is travelling forward at twice the speed of the bike.🤓
In 6000+km, with multiple bike and tire types over the years (all with tubes), my father and I accumulated the huge amount of three flats, two of them in the last couple months. Mine was caused by some dirt inside the tire, my father's on the other hand was due to some small metal shaving that made its way through the tire. Never had anything fancy, probably low cost and low performance means more material between the road and the tube
Over the last 2.5 years riding a couple times a week all over Texas and some parts of Alaska, I've yet to get a single puncture, even with Continental GP5000 tires with TPU tubes. I've always set my pressures using an online calculator.
😉 In the 'question time' at 2:49, Olli literally asks for the object's (gravitational) forces while the video revolves around their pressures, respectively, guess he was a bit in a hurry when speaking :D
Curiously, I’m running my commuter bike to work every single day, with 25mm Michelin Lithion’s and decathlon’s inner tubes. Zero flats so far (more than 3 years on that setup). On the other hand, I’ve punctured every single month on any performance bike that I have, and I mean I’ve punctured on Conti’s 5k, Pirelli’s PZeros, Schwalbe Pro Ones, Veloflexes Corsa Evos and Michelin’s PowerCup, all tubeless and many of those in 28mm spec, with all kinds of tubeless sealants (Silca, Stans, Orange Seal and others). After dealing with too much sealant hassle I’ve decided to return to tubes, and I’m now running Michelin’s Power Cups with Conti Supersonic tubes for more than a year, and I can say that I’ve probably punctured about 2 or 3 times in more than 12 months, and had to deal with a bad valve seal on a Conti supersonic tube once. All this to say that the science sometimes tell a story and the real world just finds its way to annoy science now and then 😂 I still continue to run 25mm Lithions without a single flat to date 😅
Elephants have feet, not hooves, but I love my Pirellis, my bikes are all running on tubeless Pirellis. They seat better than anything else and are incredibly reliable. I run 40s on gravel and 30 P Zeros on road. 😅👍🏼💙
just upgrade my challenge handmade tlr 27 for a vittoria corsa pro 28 and run at 3,3 bar (recomend pressure in vittoria site) so smooth ride and fast, before 4,5 bar and in the rear 5 bar
Not had a puncture since 2017.......i use zwift in winter when it's bad. But the number 1 reason is i do not ride bike paths or ride near the gutter on the road
What about the effects of tire pressure on rolling resistance? All the data I've seen on that that rolling resistance site seems to clearly indicate that rolling resistance is a lot lower at higher pressures for a given tire size.
Can’t remember last time had a puncture, no doubt will get loads now. I use continental GP 5000 and like to match the tube with the tyre so stick with continental. Have also had no problems with Michelin
Have you been running your tyres at the wrong pressure? 🛞
not really. Using Silca's tyre pressure calculator for the past 2 years. Mind you, not tubeless, for its notoriety and fussiness due to the sealant, but with TPU.
Just switched to TPU tubes on my gravel bike and checked on the silca calculator after getting a pinch flat what pressure I should be using. Turned out I'd been running at 50psi and they recommended just under 40 for my system weight and tyre width. Much comfier ride now too.
I've regular Conti 5000 25C with tubes and forgetting to pump them up to spec more often than not gets me snake bite punctures. So pumping up tires before rides is obligatory.
Because I'm lazy and ride on a variety of surfaces, I tend to inflate to a little bit higher pressure and then wait until they're noticeably lower before re inflating
No! :-) and you are overcomplicating the issue. Assuming a not rigid tire, contact patch is proportional to pressure. - No matter if the tire is 25 or 35 mm vide(!). Its as simple as Contact patch area(m2) = weight (N) / Pressure (Pa). 60kg = 588.6N, 6 bar = 600,000 pascal. 588.6/600.000 = 0.000981m2 = 982 mm2
You might be right about the elephant/stiletto thing because I have seen signs saying 'NO STILETTO'S' but I've never seen a sign saying 'NO ELEPHANT'S'.
There is no reason to ban them from being wherever they like
Have you ever seen the sign saying no apostrophes though
I’ve seen a few elephants in stilettos
“I love you, bye!”
Ollie is one of the greatest presenters on RUclips and we are lucky that he presents cycling content for us all. Always interesting, well presented and explained, with just the right amount of humour/humor to make it enjoyable too. GCN, hang on to this gem of a man!
Running tubed 25mm on fairly high pressure, haven't had a puncture in the last 30'000 km. It helps looking where you ride through.
Agree. Also citycycletracks have been killers of my tyres. Now i only ride on roads, no punctures anymore.
Same as me , I use 23 and 25c , have one bike with 28c tyres , rides awful and refuses to bank down in corners , they are awful to corner on , 23 and 25 handle 10 times better , no wonder so many crashed in the Tour de France using 32 car tyres the bloody retards , modern cyclists are being sold a load of overpriced rubbish ...Not had a puncture since 2004 when I rang the wife to come and pick me up 40 miles away , Conti Gatorskin since they came out , all my bikes have them on !
Some of my fellow club riders don't watch the road and have crashed after hitting easy to see pot holes, when driving or cycling I keep me eyes and focus on the road.
Famous words from Barry Hoban when Mark Cavendish was having lots of punctures in races ‘ He should look where he’s going ‘ 😊😊
I'm glad you arrived to post this comment.
"It's not what you think"
Turns out it was exactly why I thought
Maybe you’ve got a sixth sense 😲
+1
I experience far fewer punctures since reducing my tyre pressure. I believe a lower pressure allows the tyre to deform around sharp debris instead of being penetrated by it. It's much harder to prick a soft balloon than a fully inflated one.
On 28mm tyres I got 4 punctures in 5000km. Now I use 32mm tyres, 4500km and only one pucture so far. So, let's hope the next 500km won't be a puncture fest.
It's hard to know whether or not that is just happenstance. I've got 5000km on 28mm GP5000 (with tubes) with nary a flat.
Time to move to a different country
During about 3,000 km with new 23mm road tires I had about 11 flats. 10 of them on the front tire, and one on the rear tire.
I now have 25 or 26mm road tires, and they're a tight fit. No flats but only a few hundred km.
Riding somewhere that trashy tourists leave broken glass in the bike lane doesn't help my chances. Lucky so far - one flat on the commuter bike in 1.5yrs (glass shard in a 35mm tire) and none yet on the road bike. With the junk tossed in my space I am not optimistic for maintaining no punctures on my road tires ;(
Have 26mm front, 28mm back. 1 flat (front) in 3500km. So far so good 😅i must admit 3500km is for the outer tyre, the inner is way older than that, probably closer to 6000km or more. Netherlands has good cyclepaths.
I'm an old fashioned rider, with 27 inch rims on my road and tandem bikes. I've been running 1 and 1/8" tires for years and can count the flats that I've had in the last ten year on one hand. High pressure, up to 105 lbs per square inch on my old Avocet Model 30 Road tires. Now I'm running Panaracer Protite's, 1 and 1/8" and I've still never had a problem. Narrow tires at high pressure have less rolling resistance. Where I ride, here in Ohio, the roads are pretty smooth. I can see wider tires on crappy roads, giving you more flat protection, but on decent roads, I'll take the narrow, high pressure tires, any time.
Thank you for indulging in nerdery; it is greatly appreciated. I learned quite a bit on something that has not crossed my mind.
Just mounted my second set of Pirelli P-Zero Race TLR 30mm. Love them, haven’t had a flat in over two years!
riding 25's at 8 bar. had 1 puncture in 3 years. running continental gp3000 with butyl inner tubes.
This is super interesting! Several points genuinely surprised me, and they will undoubtedly influence my future decisions regarding tire pressure and choice of tire. I love when scientific research leads to development on new knowledge like this.
I’ve been setting pressure in the tires of mine and wife’s bikes at 15% drop for about a decade. I initially tried this based upon somehow finally fully comprehending a magazine article from the 1970s. Although all 4 of our tires are identical I have a unique pressure in each tire because of difference in F to R weight distribution and difference in her weight and mine. The 15% drop came from lab test study on drums for optimal rolling resistance. I can’t confirm the speed but do perceive it to be true. I can attest to other benefits. The most noticeable is better handling because this results in F and R tires having same size contact patch. Tires last longer because the intended width of tread is used, spreading the load and not concentrating wear along the center of tread. The GCN observation about fewer flats has no argument from me.
I’ve encountered this in aviation, manufacturing, and cycling, prior generations understood something, subsequent generations lost the knowledge, and sometimes we rediscover it.
Ollie and GCN, What about the energy loss due to compression of the air in the tyre and energy loss due to the deformation of the rubber? Compressing gas requires oodles of energy that is lost to heat (thanks for nothing thermodynamics!). Cycling 20 years ago we could ignore deformation as we all rode skinny tires at very high pressures. Today I see road bikes with 30mm and even 35mm tires at ridiculously low pressures and you can clearly see their huge contact point and deformation with the naked eye. Its no longer a negligible variable. As an engineer I'd love to see some models showing energy losses due to Crr vs. Compression/Deformation energy losses vs. Aerodynamic losses (0deg yaw) vs. tire pressure (bar) and load on tire (kg).
Hysteresis loss is smaller with bigger tyres/lower pressures.
You may find this discussion with Josh Poertner of Silca interesting.
ruclips.net/video/ZuxUWFziuGI/видео.html
The majority of the air compression happens when you get on the bike, so only once. As the tyre rolls the pressure will be constant (aside from the effect of bumps obviously) so I don’t think that’s a concern. On the deformation I think the argument is that the wider tyre gives a wider rather than longer contact patch which reduces much of the hysteresis loss you might expect if the contact patch shape remained the same.
@@robertpoll27 sounds like you have never ridden a bike outdoors. The whole point of a pneumatic tyre is to give suspension to the rider, because the 'effect of bumps' is happening *all* the time. Evenon supposedly smooth surfaces. The rider is also moving on bike via pedalling, when sprinting, standing up for hills and also off saddle when it surfaces get rougher. It's a constantly changing dynamic system which means the tyres are constantly deforming. How well the tyres deform is key to a bike's comfort, handling and efficiency.
The compression/Deformation energy losses that you are concerned about are included in the measured rolling resistance. And the one factor that you have neglected is road roughness. High pressure narrow tires have the lowest rolling resistance on ideally smooth indoor wooden velodromes, but as you move outside onto real roads, the degree of roughness impacts rolling resistance. The ideal tire matches width and pressure with the roughness of the surface. As the road gets chunkier, wider tires at lower pressures are faster.
One of the best videos that I have seen in some time.
I use 25c tyres and very rarely get a puncture.... It helps when you cycle in Taiwan and the roads are immaculate!
Básicamente, solo escribiste para burlarte de todos los que no pueden disfrutar de esos caminos 🤣😒
What?! I grew up in Taiwan and the roads were terrible to cycle on! I must live in a bad area!!! : D
I have suffered so many punctures on my 50k commute on Auckland city roads on a 55kph ebike. Most have been a "snake-bite" pinch punctures from manholes and potholes (in traffic they are sometime impossible to avoid). My carbon wheels do not allow tubeless and I am running 32mm Continental GP5000. My final solution is very involved. 1. Very think inner-tubes. 2. A "ghetto liner" (where you take an old inner tube, cut it along the inner circumference, and then place it inside your tire over a new inner tube) 3. Tyre Slime 4. A high tyre pressure, about 85psi. Finally I seem to be running puncture free.
I’ve been going up on tyre size and down on pressure every few years.
This morning I realised I know ride exactly at half the pressure I did 12 years ago and have moved from 23 to 30s.
And I do love the way the 30s feel, both comfy and fast
Gotta love nerdy Ollie. Very fascinating content.
GCN please don't put an ad for jerseys over the closed captions.
Especially when the item advertised says "out of stock" in the popup
@@Fudgeis1337 Sometimes the note shows 'out of stock,' but it refers to a specific size and colour, which means the product is available in other sizes and/or colours
@@gcntechnevertheless it’s an pain in the ass!
Hi, thanks for the video.
I once learned that the grip over pressure in NOT linear for rubber. This means there should be a optimal (contact patch) pressure for a given compound.
If I understood correctly this has something to do with the rubber interlocking with the surface, but at a certain pleasure the interlocking is complete and an increase in pressure does only slightly increase the grip.
I guess we should strive to hit this sweet spot. Or tire manufacturers should strive to provide tires that hit that sweet spot when used at correct pressure.
(just to make it bit more nerdy ;-) )
You should do more videos like this with useful data. 30/32mm wide gp5000 tires, at proper pressure, with silca sealant will make it very hard to flat. I havent flatted in a couple of years now, about 12000km and im 90kg. Using proper tire pressure and a good selant that is kept up to date is key. I hope Pirelli keep improving thier compound to catch up with GP5000. And I believe Tadej ran gp5000 28mm TT TR last year, this year he went to 30mm gp5000 S TR. And he can basically pick any wheel/tire combo he wants, so this speaks volume to that tire.
Thanks for this! Here's a case where English units are intuitively more helpful than metric. A 180 lb bike HAS to support 180 pounds. If it's distributed over 2 square inches, that means 90 pounds per square inch. (I'm a little skeptical about the statement (8:00) that there's more pressure in the center of the contact patch. Granted, central tread wears faster, but that's the area that strikes the ground most frequently. Gasses in a closed system press everywhere equally; that's kind of the point.)
maybe it has to do with the molded shape of bike tires vs. car tires?
if they're measuring the actual pressure of the contact patch, I'd expect there to be variation from the center line out, since the tire isn't flat across its surface.
@@johnhufnagel I think they mentioned that the physics of car tires was very different than bikes. A model of the gas dynamics of the contact patch might be a row of gas cylinders joined at the top. The force on each cylinder will be equal, no matter whether some cylinders are pressed in more than others.
@@johnhufnagel Contrast this with a model composed of springs in a row. Here, the springs that are compressed more will carry more weight.
I run Pirelli Cinturato 28mm tires in tubeless mode at 5.5 bar. So far no problems. Really nice tires.
I ride with 23, 25, 28 and 32mm, and so far, i prefer 25mm. I don't feel much difference with 23/25 and 28/32 are way more sluggish when going out the saddle.
The biggest factor isn't tyre width but tyre compound and the innertube. Switching from butyl to latex/TPU or even tubeless makes a big difference. And from experience riding daily with them, 28mm Hutchison sector are slippery as hell on the wet whereas 24mm cinturato are as good as on the wet as on the dry.
Silca's tyre pressure calculator actually gives me some 5 to 10 PSI higher pressure recommendations than those given by the SRAM one. I like the latter more; I feel like the recommendations by Silca are overly high, leading to a bumpier and slower ride. (With 28 mm tyres and interal rim width being 21 mm.)
and Pirelli tire pressure table recommends ~.5 bar more than Silca calc.
Doesn’t it depend on the surface you select? I find the pressure from ‘new pavement’ to be firmer than I like. I use ‘chipseal’ now and find it feels good on nicely paved areas and soaks up bumps in the poor areas.
@@danhutjens8328 Maybe if you indeed choose chipseal. I've used the ‘worn pavement’ setting, and it gives those higher pressures than SRAM.
I usually split the difference.
Prefer the SRAM one too.
Please show pressure maps across the contact patch at the various pressures.
Well done, GCN! In the late 90’s and early 00’s, I was convinced that carbon fiber technology would revolutionize cycling, and it did. What has surprised me in the years since, is how much greater the effects that improvements in brake and tire technologies have had on our sport. On our rural west Texas mountain roads, I find that my 25lb(11.5Kg) steel-framed, early “gravel” bike is just as fast on 32mm tires as my 19lb(8.5Kg), mid-level carbon fiber Cannodale Synapse is on 28mm tires. Both bikes have the same gear ranges, both have low spoke-count aero wheels, and both are running the same brand tires of the same spec. I’d put 32’s on the Cannondale, but they’re too big to clear the fork crown. Sigh.😁
Yeah ok
Late 90s was when VREDESTEIN touted their high 175psi clinchers. In my local group ride nobody was crazy enough to go higher than 120. I still have several NOS Fortezza clinchers and still think that VREDS had superior tires. But only 23mm for my Colnago Master with Mavic Open pro wheels still running true.
I still use 25mm tubular tyres work well for me
Is that tubular or tyres with tubes?
Tubular tyres glued tothe rim
@@andreemurray7039been using Paves since the late eighties...never went back to 23s . I'm a bit large so 27/28 worked out well. Still riding the rims from that Era. Wide and flat ...those have a noticeable positive impact on ride feel too....not areo though. Vitoria Special Pave was my favorite. The cool thing with the latex tubes in them is you can air them up and by the end of the day they do have a little less pressure in them oh and they make themselves anonymous while riding and ward off a few puntures along the way 😊
If you're riding vintage steel, that may be all you have clearance for.
@@christopheroliver148Nope, another myth.
As someone who has ridden in many different states, where you ride and the condition of the roads plays a huge factor in tire choice. Southern Europe and the Western US have Puncturevine (goat head thorns) that I've seen puncture many tires easier than metal/glass.
I still use 25mm tyres, but get far fewer punctures than I used to. I'd put this down to:
1. better tyres with some puncture protection
2. better pump to stop pinch flats
3. lower mileage 😞
I'm also running 25's, and since then I've reduced the number of punctures from at least one per ride to maybe 2 per season.
I noticed using tires with kevlar I have less punctures. Wider tires do give better comfort, but, don't feel fast to me.
@fredmcgough748 Going faster produces more vibrations that are felt by the rider. But more vibrations (from higher pressures) does not mean you are going faster.
"Feels fast" is a highly misleading sensation.
@@fredmcgough748 All of the data suggests that running 28's or even 30's will be faster on public roads....if you ride on perfect pavement, or a velodrome then skinny is better....but for 99% of riders wider tires will result in faster riding.
@@andrewmcalister3462it's the feeling that counts
Sorry I understand most of the content and am enjoying using wider tyres thanks to GCN. But I'm confused by the contract patch sizes and units used at 6 minutes. I'd imagine perhaps around 100 square mm (1 square cm) rather than 1000 mm squared.
4:05 - I am totally convinced now! I have never seen the elephants' tracks at any floor!
Same. We use garlic against elephants here, never seen any elephant in this country! Garlic works.
That’s why it’s not necessary to put up signs saying 'No Elephants Allowed to Preserve the Floor'
The other huge area of difference between performance automobile tires and those on bikes is heat, which is a total non-issue with bikes, but a core constraint with any car tire, and likely the most significant factor in designing racing car tires.
25mm will go the way rim brakes have. Running on 28 and 35 on my road and gravel for commuting... 1 pinch flat over 20k km (and it was me being too fast for my back wheel on a curb climb...) Pirelli Race TLR and GP5000 STR. I think the Pirellis are slightly more resistant to wear but still early to tell. Tubeless with Vittoria airliners in for added protection.
Appreciate you addressing sponsorship. It makes you more trustworthy to us viewers when we know there's sponsorship involved.
Also, elephants have feet, not hooves!
We appreciate your comment 🐘
Women also have feet, not hooves 😂
As a voice from the past, I have some comments . When narrow(25mm) clinchers first came out in the mid 1970s, I put my sew ups aside. I got more flats on the clinchers. I deducted unscientifically that the clincher rim was stiffer and worked like an anvil above the tire. Kind of like putting the tire between a rock and a hard place. As a dark horse in my cycling club, I returned to sew ups. I could wear a tire out and could almost predict the day it would puncture based on wear and road conditions. Fifty years later I still ride cheap sew ups and am happy.
Any cycling archeologist can tell you that back then ,for Paris-Roubaix there were large cross section ,very light silk tubular tires. So your contact patch science was considered back then.
Moral of the story? I think experience and the willingness to understand are important. Off road guys know how to receive the variations in the ground surface. Roadies should do this also. I call it riding vertically while going along. This is difficult in a pack , but can be done by choosing positions within the group.
I never lost a race due to a problem with my bike. I lost hundreds of races due to the other guy(s) being faster or using better tactics.
I am tall and well built => heavier than most cyclists I thought to run at higher pressures to compensate ie at 7 bar. I was made aware of the SRAM and Silca tire pressure and found I should drop my tire pressures by 1 bar. Amazing big difference in ride comfort. I still partially to sligh higher pressure to avoid punctures from the many potholes, but ti seems even dropping the pressure a little can make a big difference in ride comfort
Big thumbs up Dr Bridgewood!!!!
Just had my first proper flat that the tubeless sealant couldn’t self heal this weekend. Been running 28mm tubeless for nearly two years, so while it could be a coincidence I’m inclined to believe the science here.
elephants in stilettos. have you ever been to town on a saturday night as they can be quite common - especially around the kebab and takeaway places
Haha
Pmsl. 😂😂😂
Casual racism, sounds British
@@TheTrailRabbitI'm pretty sure the OP is engaging in body shaming, not racism.
If you're going to go all SJW, at least get your crimes correct.
@@andrewmcalister3462 no clue what you're talking about. you sound british.
Cool video. I switched to tubeless 28mm back when Schwalbe came out with the tubeless pro ones (2015ish) and never looked back. My initial reason for switch was to cut down on flats, who knew there was so many more reason to switch. I've also mastered the art of tubeless setup by making every mistake possible :)
Nice of you to point out the sponsership.
Been a year since my last puncture on road bike. I don't stress when I get one as it's easy to fix with my rim brake bike, tyre can be removed and fitted by hand, got C02 and a decent pump. Prefer 25mm tyres with TPU tubes normally, have run 28 and 32 in the past.
Sorry Olly, pretty sure Pogačar rode 30mm tyres in this year's Tour? Not 28mm.
I started riding 30mm this year, the best comfort/grip/speed I've ever had. On my C64 the ride is simply sublime. At 82kg I use 70psi (4½ bar).
And when I think back, I used to race with 23mm Tubs, 110psi, back in the 80s 😳
yup, I'm convinced 30's rule for pure road riding.
imo, 28 is needlessly small, 32 is needlessly large (and heavier).
@@seanmccuen6970 Well seeing as that Pogaćar's tyres measured at nearly 33mm, no 32mm tyres are not needlessly large. I stopped using my 28mm road tyres many years back after realising my 33mm CX tyres were just as fast and way more comfy.
@@JeremyLawrence-imajez nah, 30's mounted on 25mm internal width rims were apparently his go-to package, thus the '32mm' measurement (your words).
he wouldn't run 32's which are overkill for normal pure road riding, he wouldn't accept the WEIGHT penalty (nor the less than aerodynamically optimal tire cross sectional shape).
only time 32's are 'optimal' on a road bike is if it's wet and filthy out and/or you prioritize increased comfort over anything else.
@@seanmccuen6970 Sigh! the width of a tyre is what the ruler/calipers measure it at. Size labels on tyres are as notoriously inaccurate just like clothing/shoe sizes and they can only be accurately stated in conjunction with the rim it is fitted to. Pogaćar rode tyres that measured at nearly 33mm, ergo he was riding 33mm tyres. Not to mention that a wider rim will also be heavier than a narrower one and that weights of wheels have gone up of late anyway because the benefits of non ultra light wheels make up for the extra grams.
People not that long back said 28mm tyres were too wide, heavy etc just as you are now saying about 32mm tyres. Plus ça change.
@@JeremyLawrence-imajez lol nah, measured tire size is a product of the tire size and internal rim width (btw, I get actual tire sizes can vary re. manufacturing, etc).
he was running the overall A-1 optimal tire size of 30c for 'conventional' road riding/racing on insanely wide modern wheels which equated to around that measured 33mm figure you stated.
he was running 30's, no less, and definitely no more (per my original point).
My 28s are inflated to 90psi. Anything lower than 80-85psi feels like a flat to me. Finally used up the 23s I had, felt like a hard rubber tires at 85-90psi. My son prefers 23s, wear as I have switched to 28s, on my old Mavic rims. I ride to & from work, 22 miles round trip, and for exercise on weekends. Paved streets, not going fast so I can't avoid road hazards. Never had a flat on the road/bike path or on the Coney Island boardwalk which is why I still use tubes, however have had ONE flat sitting in the garage (aged tube), I own 3 bikes.
I have been using extra thick or thorn resistant tubes since the 90's. They are much heavier than a regular tube but I hardly ever get flats. The hand full of times I have gotten flats I was not riding on the rim making it much easier to stop. My .02
How are Michelin Airstop tubes?
like you said, tirepressure is everything. Been doing it since I started and I had like 8 punctures over 5 years, 50k kms
26mm s works turbo clinchers @ 90psi are actually pretty robust from my experience riding around beat up s England lanes
The current focus on low rolling resistance with tubeless tires is the main cause for more punctures. There is less tread and casing material compared to equivalent clinchers. Wear and durability is half what it used to be. At least sealant gets me home with small punctures.
This video is just brilliant!
Bit like record player stylus at 2 grams is actually a monster
Thanks Dr O and crew...yeah , I will check my pressure going forward !! Off road , 42's baby !!
Ollie, continue to “Nerd Out”! Wonderful information.
In 50 years of active cycling I’ve found the greatest contributor to flats is riding over debris and having it “pound” into the tread. You pick up the bit and every rotation it’s driven up into the tube. Back in the 225g tubular days we would see the debris and use our hands to brush the debris off before it could puncture. Also damp roads are doubly problematic. The water acts as an adhesive to pick up debris and a lubricant to drive it through the rubber. Over 300,000km I’ve replaced more tubes from rotting than puncturing.
On my all purpose bike (commuting groceries and touring I have 50mm tires, semi slicks never puncture and rolling resistance is rather low when pumped to near 4 bar. The reccommended pressure is between 2.0 and 4.0 bar, when the roads are bad I can lower the pressure for more comfort. In winter I mostly ride on the "dual fighter with a smooth rolling patch and more grippy profile. The nice thing about wide tires is that you have a lot of freedom adjusting pressure to circumstances. Cheap tires suck because when adjusting pressure for gravel or snow the rolling resistance goes through the roof!
6:49 Lower rolling resistance on wider tyres? No way. There is a direct relation between the contact surface of a tyre and rolling resistance.
No, there isn't - the situation is much more complicated (which is one reason why even the pros tend to use wider tires these days ...).
@@michab4083 Off course there is. Off course there are also other factors to take into consideration. Factors that outweigh the advantage of lower rolling resistance and therefore make riders choose wider tyres. Like lesser chance for punctures and the potential associated loss of time outweighs the win in time because of the lesser rolling resistance. The choice of wider tyres is by no means proof of a lesser rolling resistance. Why do you think sports cars need wider tyres? Exactly: for more grip (or ground resistance)
@@michab4083 One thing seems for sure. If you are a 55-65kg pro, riding pro speeds, those 28mm tires most of them use must be fastest. Couldn't imagine otherwise. The situation for mere recreational riders might be very different. I personally find those wider tires more pleasant to ride on, and if folks pass me because they are fitter or have faster gear, good for them.
"I love you, bye!" 😂 Hey we love you too, Ollie!
No discussion about the type of tube and its effect on the tire patch. There must be a difference between butyl tubes and TPU tubes, and I bet the difference is that the TPU tube has less rolling resistance. I heard somewhere where a TPU tubed tire runs with almost the same resistance as a tubeless tire. So the TPU'd tire will be lighter (no sealant), almost as fast as tubeless, and none of the mess and hassle of tubeless. I've been running TPUs on both my road and gravel bike for over a year now, and love 'em. Give it try if you're considering it. TPUs are expensive, though, but easier to patch than butyl.
contact patch area = gross weight / tyre pressure. If the tyre has carcass strength then ground pressure can vary across the patch and the patch will be smaller.
I’m not sure about the effect on punctures, but I just learned the lesson of wider tires at lower pressure and the ride now never felt better in my life. I was riding 25mm tires at 120psi! I’m 200lbs so my rims and tires hated me. 😂 After a spoke break and splitting side walls, my local shop recommended 28mm at 90psi or lower.
I was baffled when my colleague that shares my commute route had WAY less punctures on his 25mm tires compared to my 35mm gravel tires.
The reason we found out was shells from acorns and other nuts, they "skid" off of his tires but get stuck in the more aggressive profiling of my tires.
Then again I run tubeless and just keep on cycling and he needs to change his innertubes :D
Thank you, I do like this nerdy level of investigation and explanation.
I got one puncture in four years / about 40k km's, and I ride the shittiest b-roads, forest roads and rocky gravel. Proper pressure, considerate line choice, wide(r) tires and running mostly tubeless prevent a lot of headache.
I recently changed from Maxxis to Pirelli.... OMG... It was like I found god.... I am doing 3 to 4km/h faster and the bike now feels sexy on the road... Love them love them love them.
I run tubeless and haven’t had a flat in several years. The last one was a long sliver of steel that cut a slit the tire.BTW I ride gravel, road, and a bit of trail/mountain bike.
Ollie..I thought that was super interesting and you did an excellent job explaining the science in understandable terms. Also, that blue sweatshirt is your color man
I would love to see a video where you folks test out e-bike range with a variety of tires at different pressures.
I used Goodyear eagle f1 Supersport front 25c really good puncture protection
Good, useful content Ollie: thanks. (Notice my lack of snark, for once? Wonders will never cease.) I like Pirelli tyres. They last pretty well, roll pretty fast, and are ever so slightly less expensive than Continental. One of their gems is the vanilla P Zero - not the 'Race' model. £10-20 cheaper than the 'Race' (let alone the RS) model, with about 90% of the performance (slightly less grippy tread, I think). A little bit hard to find: I think they/importers/retailers know these are a good value (read: lower profit margin) tyre. For those of us who go through tyres like underwear, this is an advantage: keep the gee-whiz £££ tyres for Sunday best, put some almost as good lookalikes on for trucking around on during the week (or for superannuated hacks like me, use them all the time) and let people think you're running £100 tyres ALL THE TIME and make it look as tho you're rich or sponsored (hah!) or summat lahk tha'.
Pinch flats were mentioned, but there's another factor as well. Given a fixed size defect in the road surface, say a 1/2" rock, the danger of totally compressing the tire is much greater for that 18mm tire than a 28mm one.
I believe you stated the question incorrectly at the start: 'which vehicle puts more *force* at the bottom of its tires?' The force is the total load, not just the pressure. A tire with a 100lbs load will put 100lbs of force into the ground, but the smaller ther tire, the higher the pressure.
I actually genuinely can’t remember the last time I got a puncture on the road, it’s at least a couple of years ago, probably at least 12,000-15,000 miles since I had a puncture in road riding, and I use race tyres year round on crappy British lanes full of debris and pot holes. Running tubeless tyres between 25 and 32mm across multiple bikes, at modern low pressures as recommended by the SRAM calculator.
I did have a sidewall puncture a few weeks ago - but that was doing a rough gravel descent at speed on road tyres, so can’t really count that! I put a plug in the tyre and then did another 500 miles to complete the ultra race I was doing without problem.
Regarding how intertubes affect the contact patch and pressure: what type of intertube was used? Butyl, latex, or TPU
I changed my 23c to 25c from 100 PSI down to 70 PSI and all is so much better , I was under the impression my Mavic wheels can not go any wider ….
Just stared last year. No punctures in 5000km. Riding in the lane; not on the debris-filled shoulder, (as much as safely possible). 28mm & 30mm @5ish bar
I’m still using 23mm tire because Zipp says that they make my 2011 808 Firecrest wheelset more aero. If I go bigger the rims are less aero. I would need to buy new wheels to run wider tires.
Ollie - you is a scientist mate! Pressure is Force / Area, so the tyre pressure and the system weight almost totally determine the total patch area. For example, my system weight is roughly 155 lb + 20 lb = 175 lb. Let’s call it 180 lb for fun with full water bottles. Now if I have 90 psi in each tyre (of course I do not I read the Silca pressure calculator too!) and equal weight distribution then each tyre bears 90 lb with 90 lb / sq-inch so the total area of the contact patch on each tyre must be 1 square inch. Of course the SHAPE of the patch must vary (wider tyre = wider side to side and narrower front to back) and the properties of the casing will have some effect to the extent that tensile forces distribute some of the load (so the actual patch area in contact with the surface will be marginally smaller than 1 sq in). I assume that the tensile redistribution is small, but if later in the video you reveal this is wrong that will actually blow my mind (that would be like those nifty string spokes Pidcock and Ferrand-Prevot rode to glory…).
i saw the video and have no idea why my bike tyres get more punctures but i should choose pirelli because they think about it
aside from that i think its tyre (training tyres can be slower but more durable), roads you ride and your attention to obstacles that can puncture you
Thanks for the really interesting info. Knowledge is not nerdy.
@oli don't forget to mention for a non-skidding tyre, the contact patch is stationary and the the opposite side of the wheel is travelling forward at twice the speed of the bike.🤓
In 6000+km, with multiple bike and tire types over the years (all with tubes), my father and I accumulated the huge amount of three flats, two of them in the last couple months. Mine was caused by some dirt inside the tire, my father's on the other hand was due to some small metal shaving that made its way through the tire.
Never had anything fancy, probably low cost and low performance means more material between the road and the tube
Fantastic video; thanks! I wonder if the innertube material makes much of a difference; butyl vs latex vs pvc ..
Over the last 2.5 years riding a couple times a week all over Texas and some parts of Alaska, I've yet to get a single puncture, even with Continental GP5000 tires with TPU tubes. I've always set my pressures using an online calculator.
😉 In the 'question time' at 2:49, Olli literally asks for the object's (gravitational) forces while the video revolves around their pressures, respectively, guess he was a bit in a hurry when speaking :D
Curiously, I’m running my commuter bike to work every single day, with 25mm Michelin Lithion’s and decathlon’s inner tubes. Zero flats so far (more than 3 years on that setup).
On the other hand, I’ve punctured every single month on any performance bike that I have, and I mean I’ve punctured on Conti’s 5k, Pirelli’s PZeros, Schwalbe Pro Ones, Veloflexes Corsa Evos and Michelin’s PowerCup, all tubeless and many of those in 28mm spec, with all kinds of tubeless sealants (Silca, Stans, Orange Seal and others).
After dealing with too much sealant hassle I’ve decided to return to tubes, and I’m now running Michelin’s Power Cups with Conti Supersonic tubes for more than a year, and I can say that I’ve probably punctured about 2 or 3 times in more than 12 months, and had to deal with a bad valve seal on a Conti supersonic tube once.
All this to say that the science sometimes tell a story and the real world just finds its way to annoy science now and then 😂
I still continue to run 25mm Lithions without a single flat to date 😅
Ollie, one for the next party riveting conversation 😂 good stuff though. Do find with 28s at 60-70 psi, few punctures this past 2yrs
Pogacar’s win this year was actually on 30’s (that had an actual width measurement of greater than 32)
GCN does science without glasses and white coat 😂
Safety comes first; we should get a pair ☝🤓
I am running better pressures than what I use to run. But now I understand why bicycle tires don’t have mileage warranties.😊
absolutely great explanation and conclusion to the topic
I believe the '24 TdF was actually won by a certain T.Pogačar running 30mm tyres
Something nerdy for you: A railway locomotive with 8 steel wheels running on steel rails has a contact point the size of a 5p piece.
Elephants have feet, not hooves, but I love my Pirellis, my bikes are all running on tubeless Pirellis. They seat better than anything else and are incredibly reliable. I run 40s on gravel and 30 P Zeros on road. 😅👍🏼💙
I've been riding GP5000 in different sizes and versions for about 20,000 km, and I've had just two punctures 😂
just upgrade my challenge handmade tlr 27 for a vittoria corsa pro 28 and run at 3,3 bar (recomend pressure in vittoria site) so smooth ride and fast, before 4,5 bar and in the rear 5 bar
Thank you, love the science!
Not had a puncture since 2017.......i use zwift in winter when it's bad.
But the number 1 reason is i do not ride bike paths or ride near the gutter on the road
What about the effects of tire pressure on rolling resistance? All the data I've seen on that that rolling resistance site seems to clearly indicate that rolling resistance is a lot lower at higher pressures for a given tire size.
Can’t remember last time had a puncture, no doubt will get loads now. I use continental GP 5000 and like to match the tube with the tyre so stick with continental. Have also had no problems with Michelin