I use 4.3 bar at the rear and 4 bar at the front, because the roads are really bumpy where I live and I use 28mm tyres, and I only weigh 63kg so I'm not that heavy
Rough and bumpy roads. I'm a road cyclist and never ride on anything other than roads. However, finding a decent, smooth, pothole free, good condition road surface is a novelty. So much so that if by chance I find one, I turn round and ride it in both directions.
@@HFields That's because you are in a country that has the foresight to invest in it's future. Here though, we simply don't. Everything on the cheap then wonder why it's broken. If it wasn't so utterly depressing it would be laughable.
At age late 70s I road for years at 120 or higher on 24 with tires and it was dangerously a hard ride. I now ride at 100 and looking forward to ridding this coming year at 80.
I love an endurance ride 150-250km on a Sunday so reduced vibration is very important with respect to rider fatigue. I’m 90kg and ride with a 28mm up front at 80psi and a 32mm out back at 70psi on Hunt Supa Dura wheels which are designed for 28-32mm tyres. Roll well, soak up vibrations and also great grip in the wet. 28mm is a GP500 (Conti) 32mm is a 4 seasons (Conti) In summer I ride 85psi up front and 75psi out back, it’s a bit drier on the roads and less mud etc.
Good video - just wondering if there is also a way to work out how pressure affects the risk of getting a puncture - this is an especially important consideration for those who use their bike to commute on bumpy roads!
A lower pressure will resist punctures better because the tire will conform over debris. When a tire has very high pressure and is prone to a puncture much easier. Think of it like a balloon that's half deflated it's very difficult to pierce. But a balloon blown up to its maximum is very easy to pierce.
Would have been interesting to see you refine it even more, say try 70psi then go 5 either way depending on what 70 showed. Also would have been handy to know what the wheels are, so what the rim dimensions are?
100% correct. When I went from 25mm to 28mm tires, I started with a bit higher than the recommended PSI for my set up and weight, then I did the same exact ride few times a week reducing few PSI per ride (about 3 at the time) until I found the sweet spot. I went from 97/95 on my 25mm to 67/65 on my 28mm (different wheels of course). It took me few weeks, but it was definitely worth it the time and I wouldn't go back!!!
@@georgehugh3455 Just go to the ENVE or SRAM tire pressure calculator (I used the ENVE chart). Depending weight, tires size and your wheels internal measurement you can calculate a pressure to start with. I have tubeless set up and my wheels are 21mm internal and I use 28mm schwalbe. I weigh about 175lb. My local roads are in pretty good shape (obviously not like a velodrome), but you can definitely feel a difference in comfort. As a matter of fact, when I went under the sweet spot for me was SUPER COMFY, but the bike felt really slow accelerating off the saddle, so I went up in pressure a bit after that ride.
@@georgehugh3455 If you're curious to have another similar feedback, I weight 145lbs and when I switched from 25mm to 28mm Tubeless, I lowered my pressure "Front/Rear" from 90/100psi to 55/65! I always have 10lbs less in front cause 55% of the weight is at the rear as a chart I saw long ago. Roads are quite shitty in Quebec "Canada". The difference was night and day, no way I'm going back to 25mm ever!
Agreed. After riding at 125 psi on 23 & 25 for a dozen or more years. I did a similar exercise and the-new t/p is 25 psi lower on 25 mm tyre , improving handling and comfort immediately. Make the adjustments across on 32 & 40 with immediate results and will continue to hone in on the sweet spot for 28 , 32 & 42 mm tyres.
When I went from 25mm to 28mm tires, I started with a bit higher than the recommended PSI for my set up and weight, then I did the same exact ride few times a week reducing few PSI per ride (about 3 at the time) until I found the sweet spot. I went from 97/95 on my 25mm to 67/65 on my 28mm (different wheels of course). It took me few weeks, but it was definitely worth it the time and I wouldn't go back!!!
Interesting. How much do you weigh? I'm preety heavy for a roadie 92kg and I ride on 28C Schwalbe Durano on 100psi/7bar and I never had a flat and I ride on harsh roads mostly.
@@Jurica-mtb Just go to the ENVE or SRAM tire pressure calculator (I used the ENVE chart). Depending weight, tires size and your wheels internal measurement you can calculate a pressure to start with. I have tubeless set up and my wheels are 21mm internal and I use 28mm schwalbe. I weigh about 175lb.
@@robbiddlecombe8392 my pressure isn't going to work out the same for you. I went to the ENVE pressure chart and got the recommended PSI for my set up (66 psi in my case). Since I was use to 97/95 on my 25mm tires, I didn't want to start so low and that's how my whole test began. In every single ride I would log my pressure in STRAVA so I could compare my data at home after syncing with my bike computer. Per ENVE Chart, if you are between 170 and 180 pounds, for 21mm internal wheel size and 28mm tires, the recommended pressure is between 66 and 69 PSI, but once again, that should be just your starting point for testing.
@@robbiddlecombe8392 I'm not really sure, I'm not an expert on wheels or anything like that, I just followed the chart and it worked for me. Are you running tubeless set up? (When I say that it worked for me I mean that at the same watts I increased my average speed like 1 mile per hour if I recalled well).
@@robbiddlecombe8392 Yes, I run tubeless and I love them. 3 seasons with them, only 1 flat that I fixed with a plug. I don't even carry a Spare tube anymore(I did the first season that I switched to tubeless).
My understanding is that tire companies optimize side wall and tread design to operate best at 15% rim drop. For me, that's 47 psi front, 55 psi rear on 32mm tires. I was pleasantly surprised to find that this not only rode a lot smoother, but handling and stability in corners also improved vs higher pressures.
I am using the exact same pressure as you with 28mm tyre on 18mm rim. For 32mm i use 3-5psi lesser. I am 63kg. My bike feel smooth and fast and super enjoyable to ride
i like the idea to use your phone to objectively measure vibrations. about the experiment: it would be important to repeat runs with the same settings to see how consistent the results are. then it would be possible to say whether the differences are real or a statistical artifact. about too high pressure: I think that often feels fast because you feel more of the vibrations through the frame. testing wheel rolling resistance in the lab is done on a smooth surface. on a real road less pressure can be faster because the bike does less horizontal movement.
Much agreed with multiple runs and smaller pressure increments. I would also take it a step further repeat the experiment with some potholes and cobbles - those results would be interesting as well. Great work overall :)
Thanks for doing this test. Something I'm constantly changing is my tyre pressures. I'm not the fittest or youngest (51 years old) so always thought that riding with the highest psi (120 on my current tyres) would allow me to ride at my fastest and use less energy so long as I can put up with the harsher ride. I'm currently experiencing discomfort around the back of my neck and I'm guessing it's down to the harsh rides I've recently done. After watching this video I am now going to reduce my psi to 80, I totally get why you experience a faster ride with the slightly less up and down movement which is actually a lot of wasted energy.
I always run a slightly lower pressure on the front to help with grip (especially in the winter). I find my ideal balance between speed & comfort is 95 rear (as I'm a bit lardy..) and 90 at the front. However, after seeing this vid I might try 85 at the rear and 80 at the front. Really useful vid Alex! :-)
These results fall in line with my experimental experience. With both 25 and 28mm tires and 85kg of heft, I had found that 80 psi was my magic number. But after a winter and some more testing, I prefer the 75 psi. Much smoother at least and my avg mph is a bit better even! Thanks for the number crunching, Alex!
Have you tried the soapy water trick? As Gary said... more tape might help. Also (if you're not already doing it), you might need a compressor or a chargeable pump.
Interesting video, illustrates the difference between a "Road Bike" and what we used to call a "Hybrid" usually used on the road or cycle tracks.The bike I normally use has suspension forks and a suspension seat post, 44mm tyres running at their rated maximum of 4.5bar. If traction is compromised for mud or ice I reduce the pressure by 1-1.5 bar. The bike then feels "soggy". No more comfortable just less agile, and harder to pedal.
Great concept for a video, I do wish with all these that the sample size went up a bit. You can always do repeat runs off-screen if it's boring, but would make the outcome so much more reliable. The 2s difference between 80 and 95 psi could easily be from a couple of windy gusts or a slightly different line taken. Taking an average of 3 would really mean something
My thoughts exactly - but this is GCN not a scientific journal! That bit when Alex was checking that the tyre was at the target pressure of 100 psi, saw it was at 95 and said "that'll do" tells you all you need to know! 🤣
I swiched back to 25 mm tires and 8.0 bar in latex tubes. It's way more fun than a 32 mm tire with 5 bar - no matter what the current trend says. It was such a great feeling to be back on a real road bike. Thin tires and high pressure are - in my learned opinion the fastest thing you can ride on a good road. When I want to ride my road bike I plan my routes picking the best possible roads available in the area and ejoy it. I know that low pressure will be better if the roads get worse and sometimes it can be anoying if these kind of roads cannot be avoided. But I don't want to win races. I am out there for the 8 bar on smooth concrete in narrow tires feeling. This is something you cannot get on a low pressure bike. If there is a tour on which I cannot avoid rough roads - I will use my gravel bike
I usually use 60psi on my winter tyres (32c alloy wheels) and a manufacturer recommended 80psi (28c Hunt carbon 44 wheels) . The summer tyres are definitely less comfortable but do feel quicker.
As an added bonus, tyres at lower pressures will deflate slower than tyres at high pressures. Anecdotally, I know, but running my tubeless tyres at between 75 and 80psi, I'm not pumping them up as often as when I ran that 90psi.
I'm an 80kg rider and I've always felt comfortable riding 100 in front and 115 at the back, both wheels are 25 Anything lower than those felt uncomfortable so I can't relate to what's shown here that lower pressure equals to more comfort I guess weight of the rider does play a huge role on this matter
Great video, GCN! Any chance we could see how the road surface and tire pressure affect bike speed when you're actually putting down effort? Might be a great opportunity for a test using an e-bike pushing a steady (x)w. Also, as someone else pointed out, an average time from 3-5 runs would help compensate for wind, slight changes in line, etc. Again, great work!
My lower back has really thanked me for dropping the pressures over the past few years. Although 80psi on 20mm race tyres back in the day probably wasn't doable.
I enjoyed this - no, it's not a perfect test (more runs would help), but I like the approach. More importantly, I love Alex's new Orbea. That color scheme is beautiful.
Honestly, more data only helps him, it doesn't help us, there's just too many variables: rider weight, tire material, road surface etc. He's shown how to do the test, now we can run it for our system and location.
interesting. i notice that when I pull the track pump's nozzle off the valve then put it back in the tyre loses 5-10psi so maybe worth putting the extra in to account for this. 80-90 seems a good pressure for 28mm for most real world conditions
I think you don’t lose the pressure by taking the nozzle off, you “lose” it by putting it back on. Because the air goes from your tire back in the pump. More volume-> less pressure
😆 Why would you put the pump back on after you’ve pumped it up? You’re only letting the air out of the tyre to repressurise the pump chamber. If you add more in to account for this pointless step, and then don’t do that step, your tyres will be over inflated!
@@stevenrholland when we take the pump off some times it gets kind of stuck and you hear air escape. We mistakenly would put the pump back on to check the pressure not realizing that it was only making it worse.
your test was on smooth road surface, for the roads i'm stuck with near where i live the 80 or even 75 would result real good because of less hard tire bumpiness losing efficiency. I typically run 80 rear and about 76 front.
The weight of me and my bike & the bits and bobs i carry is about +120kg, i usually run a 100-110 PSI, anything lower, it feels like I'm riding on the rims and really squidgy/squirmy on the corners.
Yup, this tire pressure is only optimized for him and his current set up. Different tires, different weights, different surface conditions all change the equation. Only way to know what works for you is to go find a hill with like surfacing as you intend to ride on and ride it with different pressures under as close to like conditions as race day to see which is best.
GCN needs to read up on tire impedance. BicycleRollingResistance's tests and other smooth-ish drum dynamometer tests don't show the effects of tire impedance. Tire impedance is the loss of energy due to rough surfaces (that's way oversimplified). The effect impedance is that it limits how high tire pressure can go. Practically that means that as you increase tire pressure (and cRR goes down), there will come a point beyond which cRR starts to go up. That point varies from surface to surface and tire to tire. Leonard Zinn, Josh Poertner, Tom Anhalt, and others have looked into this. There's lots of data online. Also, the comfort factor can't be overlooked, and that factor may actually be a performance-limiting factor. I'm not sure what research has looked at this, but it has been suggested that prolonged exposure to certain ranges of vibration frequencies (and likely amplitudes) can lead to earlier fatigue and may have other effects. There's likely merit to the idea that a more comfortable rider is a faster rider (I don't mean beach cruiser, big cushy seat, and upright comfy). You guys might want to consider a test. Find a rough road and compare how riders feel over the course of and hour or three, wherein one rider rides at lowish pressure while the other rides at really high pressure (Maybe 60 or 70 psi vs 110 or 120 psi).
Thanks - was looking for a post like this (before I had to write it). I would add that typical UK/Pacific NW wet road conditions also add a slip/grip factor that improves with a reduction in pressure. Higher pressure helps avoid pinch flats for tube users, creating a practical lower limit. The right tire pressure is usually the result of a few compromises.
I ride 32mm tires at close to maximum recommended pressure, 100 psi/7 bar. I think 80 psi is only marginally more comfortable than 100, to be honest, with noticeably more rolling resistance, and at lower pressures I tend to get quite a few more punctures on our poorly maintained US roads. I also suspect, admittedly without hard evidence (no pun intended), that fully inflated tires tend to last a lot longer than ones run at lower pressures.
Lower pressure will actually decrease puncture probability not increase it. Lower pressure will allow the tire to conform over debris rather than being pierced like higher pressure tires. It's mostly down to perception. Go check out Jan Heine from bicycle quarterly, he's been doing in-depth research and Analysis on tires and pressures for over a decade. He has so much information there it'll make your head spin
Ive just got a speed bike and from my lil xp if I run on 85psi (Im 70kg) its more likely to get a flat tire when I hit medium imperfections on the road, as the tire "bites" the ground. So Im now riding with 100-110psi and I can feel it goes much easier \ô/
I had doubt at first bout whether tyre pressure do make a difference. I used to run 100psi all round. But when i drop it 90 -87 psi. Major difference. Smooth and stable. Also comfortable considering where i live road surface are horribly paved.
It all depends on many factors of course. But generally with my road bike I usually start with the pressure between the max and min recommended pressure, add 5 to the front and remove 5 from the back from that, then refine from there to find the most comfortable pressure with least rolling resistance. I find this varies greatly between tires hence I didn't put a specific pressure down. My mountain bike it's a little different, if I'm going to use it on the street then I simply run the min recommended pressure. Then off road, I find I often run well below that recommendation. Again, I didn't name a specific pressure because it varies greatly between different tires, but also the terrain really can take on an equally important role in deciding this.
Maximum and minimum pressures are nothing but liability tags. You can basically ignore them because they don't mean anything the manufacturer does not want you to run Tire lower than their minimum recommendation or higher than their maximum recommendation. It has nothing to do with performance. To find the right pressure it takes much experimentation and even more so on a mountain bike
@@rider65 little more to it then that (they have reasons from wall stiffness (tire folding onto it's self), rim protection, blow outs (more likely to happen at low pressure then high believe it or not), etc. But it would be far too much work for them then just give a general guideance.
Thank you for testing all this stuff, so we don't have to! :-) But please do this again uphill to see how much power the elastic deformation eats with each step. I guess it might be the best choice to ride 100 psi at the rear wheel and 80 psi at the front wheel at your weight.
Your tire pressure should depend on 1) The size of your tires, 2) Your weight, 3) The condition of the roads you ride on, and 4) How observant you are (whether you "ride light" or "ride heavy") I tend to still ride with a 23 in front and a 25 in back, and both at 95 psi, ever if I've put on a "little" weight in the last 35 years.
Was going to make the same point. Lots on here concluding 80psi is the best pressure but totally dependant on tyre size and weight. For me at 85kg I go up to 105-110 in summer, good roads on 23-25 mm and high tpi cotton tyres, down to 90 winter w/25's. 80 or lower would feel a little sloppy for me at my tyre width and weight
Well I can tell you Bill that a bit of you're thinking is outdated. If anything you want the wider Tire up front for improved traction and braking. Checkout Jan Heine from bicycle quarterly and all the data on tires there is a ton of information there that will change your way of thinking.
@@rider65 Nobody who rides on pavement does that. That said, I have to say that my Mountain bike is set up that way, with a slightly wider, with more knobs, in front. Riding on pavement and dirt is completely different.
Ok, how did you run 40 without getting a puncture? 40 is what my mountain bike is at when riding on road. That's a 2.3 inch wide tire, 58.42mm. Granted my road bike is a 23mm but I get punctures under 100psi.
I have those same tubeless tires and I use the manufacturer recommended tire pressure chart. Their recommendation are higher than my regular clincher set up.
I’m running tubeless tYres with lower pressure. Interpolating your figures it would seem that 70 psi would be the optimum tyre pressure for speed and comfort.
@@sventice as am i. In three years ive had two punctures, it was only the next day did I notice a damp patch. The last one a stan’s dart sort that out 18months ago been riding on it every since. I found the mavic tyre pressure calculator to give lower pressures than the zipp calculator. Both calculators give numbers im happy with but about 70psi is a good number for me.
You are not wrong, but the fact is most people don't have an indoor hill. In lieu of that, once you feel you're in the neighborhood of where you need to be, you can start to collect more data to validate your results. If you're doing hill climbs once every week, do 3 at each pressure (12 hill climbs in one season) and at the end of the month you'll have a very good data set (12 samples at each of 4 pressures).
I think given the accuracy of the equipment, not under lab conditions, margin of error, number of tests i.e. just 1 per category etc. I don't think you can really draw definitive conclusions for a couple of seconds between 100psi and 80psi for example. I would agree that you can probably show the general trend i.e. lower psi will result in a more comfortable ride. Anyway, that criticism aside, enjoyed the video as I do all your videos. Did you have inner tubes on by the way as I know tubeless are usually on lower pressures anyway?
I changed my 700 x 38c hybrid tyre to a 700 x 32c road tyre on my Giant Hybrid bike with front suspension forks. I had both at 80 psi and the 32c tyre is more comfortable. Maybe the 32c tyres have more tread or thicker being newer but the difference is amazing. Also the bike is faster with 32c tyres.
yes, hybrid tires are very beefy, many have thick puncture protection layers and thick hard sidewalls. they are designed to last a long time with low maintenance, and the construction is also mostly way simpler and cheaper than road bike tires. they stay harsh and wooden feeling even at very low pressures. a high end road bike tire can feel like silk against that, even at higher pressures.
I thought that the main advantage of lower tire pressures was power being more easily transferred to the rear wheel on bumpy surfaces. This could also be a good experiment to make (constant power output vs. speed vs. tire pressure).
Definitely another advantage to running lower pressure on real world roads is the larger contact patch of the tire allows you to deliver more power to the road to the point that it is a bigger difference than the added rolling resistance. GCN did a video (actually a couple I think) on this a few years ago.
I used to use about 100psi but was loud and clattery and harsh and uncomfortable on my specialised Tarmac. I wanted to improve things. I tried 95psi and did some out and back runs in a set time recorded the ave wattage. I dropped to 85psi and repeated runs. Did the math. I saved 3.5% power with the 85psi. This was 7.6watts saving. I was about 90kg. Bike is about 8kg.
So, overinflated tyres bounce over bumps, reducing speed, and underinflated ones are too slow. No s***, Sherlock! When I was an audiophile, I found people believed wires made all the difference and would buy 20,000 $/€/£ speaker cable sets. Then I turned to photography. They're still debating an arcane "equivalent aperture" concept and buying 20,000 $/€/£ lenses to have the maximum aperture. Now I'm a cyclist. The same gullibility, with people ready to believe wider tyres are faster. Is there a hobby where they don't throw a lot of BS at your face? If there is, please let me know. (In the meantime I swapped the 700x35 tyres on my hybrid bike for a 700x32 set of tyres. Although I could easily believe my bicycle became slower due to the extra narrowness, the fact that I keep taking time off my rides' duration tells me otherwise.)
I pick a stretch of the road I am going to ride, and start with tires pumped up obviously too hard, and repeat that stretch with lower pressures until I just barely feel the road. That gives enough pressure to protect the rims and not have any squirm. Any lower doesn't improve anything for me.
i’ve forgot, but isn’t it around 80psi for road race and 60 for mtb.. i like them tight, and if they feel slippery you can always release the pressure for a millisecond
Interesting Alex, what about the benefits to rolling resistance of tubeless, and the fact that hookless rims tend to have a maximum pressure of 70psi, and that nobody recommends running 28mm tyres at 100psi anymore? All the recent rolling resistance findings seem to be that super flat tarmac benefits higher pressures, but typical UK roads would benefit from lower pressures. Your test was on a descent as well, so pedalling over deformations in the road would have shown a difference I think? Vibrations feel fast, but aren't is often the thinking. Having watched this, I'm planning on upping from 70 to 80 psi and trying to take the smoothest path on the road - running GP5000 TL 28mms on Hunt hooked rims. Thoughts? (anyone)
@@richardggeorge i also factor in just what I like... my perfect comfort/ feeling fast mix. Dont really care if lower is theoretically faster if I then feel like I just ate a whole cheesecake...
Awesome experiment, i really enjoyed it. On both my old bike and the new one the pressure inscripted on tires was 3bars. Continental and Maxxis 2.2 and 2.1 . Problem is at 3 bars it becomes extremely hard! At 2.7 is still very hard, 2.2 seems to be appropiate. I wonder if 3bars is the maximum allowed or the recommended...
Question: The "SRAM tire pressue guide" calculator suggests pressure of around or even below 2 bar (down to 1,66 bar) for my use-case of a 50-584 tyre (Continental Contact Urban). However, the manufacturer specifies 2,5-5,0 bar pressure. Can I nevertheless set the pressure (much) lower than 2,5 bar to match the SRAM values? What can happen if I stay below manufacturer's recommendations? Any experience?
It’s funny no one ever addresses the possibility of pinch flats or rim damage. Just speed and comfort. How fast and comfortable are you sitting at the side of the road fixing a flat. 100psi for me
Okay, I had an old Bianchi with 23's, top pressure was 110 PSI, now I've got a new bike with 32's, top pressure 80 PSI. If I remember correctly, I'd ride the Bianchi at 100 PSI, and I ride the new bike with 70 PSI
What handlebar is that? It does not look like the standard two-piece stem and bar Orbea offers on the Orca Aero. Were any modifications needed to run that integrated bar?
Can you tell if riding 25 mm tyres at 80 at the front and 85 at the back, I am 71 kilos or going for wider tires at a lower pressure would make that much difference to my shoulders, I have just had double shoulder replacement and all my bikes can only take 25 mm tyres and I don't have much money, I have a Dawes Galaxy which can take bigger tires but is heavier, not sure what to do x
I have Vitorria 28mm tyres but the side wall says the pressure range starts at 87psi. Is it safe to inflate under this minimal limit? Do others pay much attention to the side wall recommendations?
Would the results be less significant for lighter riders and slower riders? ie the vibration loss isn't worth the gain in friction. I'm 60-62kg and a new rider so i'm down in the 25-30km/hr still, riding an entry level road bike with tubed tires at 100 psi.
I've been running 80 PSI since I switched to tubeless and I was actually thinking about dropping that down to 70 now that I'm going back to 28's, but 80 seems to be about right
I mean honestly go as low as you can before the tire impact the rim on bumps and potholes 80 psi maybe optimal but it's really perception. There is a Tipping Point between the very lowest and very high pressures for optimal traction and performance. It may be 70 but you have to experiment it may be somewhere in between.
Does freewheeling count less than contact time with the tarmac? I thought lower tyre pressures allowed more contact time when pedalling hence more efficient use of power, we have all experienced bouncing with higher pressures.
So it appeara that 80 psi, or roughly 5.5 bar should be the quickest in terms of rolling resistance. What about hookless rims then, since the maximum pressure they are allowed is 5 bar?
interesting vid... just curious on your body weight and bike size to adjust to my own size. i run a tcr m/l frame and weigh 178lbs at 85 psi. just throwing that info out there
Let's not be obsessed with accuracy here... First off, it's not as high as you might think. - The pressure gauge has a error margin, as do your phone sensors, etc. Changing your tire temperature by around 12 degrees C (difference between when you set off and a few minutes of riding or moving from shade into sunlight) will result in a 5% change in pressure. Tires are not the only thing suppressing vibrations. What about the stiffness of the frame, fork, stem, handlebar, wheel profile etc. Soooo many dynamic variables - none of them sadly mentioned :-/ Secondly, as noted at 1:03 the difference between a 100 and a 120 psi tire is 1W, for 100 vs 105 it will be about a quarter of that - not sure what to compare it with... Possibly trimming your nails? A new cyclist might watch this and think they need to get their pressures right up to a single psi, which is just silly. Literally all you really need to do is follow the tire manufacturer guidelines and you're good. Pirelli recommends 80psi for the 28mm P Zero TLRs for a rider between 76-85kg. - Which is exactly the result that Alex got. Shocking, huh? A little disclaimer at the end about that would be good.
Highly informative. Much obliged for your good work here. Stunning to see a quicker ride at 80 psi than 100. There are more things in heaven and earth, Horacio, than are dreamt of in your philosophy, as your fine countryman has it.
I think the sweet spot is below 80 psi. Even if the speed is slightly slower under this test condition, it cannot be mapped to normal riding. This is because vibrations that are not absorbed by the tire have to be absorbed by the person riding the bike, in the muscles etc. So the vibrations not absorbed in the tire are tiring(!) (lol) your muscles and as a result make you slower on a longer tour. This has to be factored in, and as a result the OVERALL sweet spot is somewhere below the "seemingly optimum" tire pressure under the academic test conditions not factoring in this effect.
@@hkremer3234 yes I'm on hooked aswel some camy boras. personally I'm not a fan of hookless. All it really benefits is the manufacturer in cheaper production costs. the watt savings for the customer are so small it's probably not even worth mentioning
It takes energy’s to vibrate your body.. that is energy that‘s being taken away from bike moving forward! Vibration losses are minimized by lower pressures (energy lost from vibrating rider and bike).. rolling resistance losses (from bending tire carcass) are minimized with higher pressures.. therefore, for each tire on a given surface there will be an OPTIMUM pressure.. higher is not better. Most rolling resistance tests don’t take into account a rider sitting on bike sopping up vibration and bleeding away from forward motion in form of heat into environment. VeloNews and WheelEnergy did a test where they used a textured rollers and an air shock as a stand-in for a rider and demonstrated these vibration losses (compressing air shock likewise bleeds off energy as heat) though not as much as a rider likely would!
I'm not sure if we can assume that a lower pressure is faster overall. In this test it was faster going downhill without pedalling, but would the higher inflated tyre transmit more power to the ground when pedalling and be overall faster?
No, literally the exact opposite. Unless you are biking on a glassy-smooth surface, very high tyre pressures increase rolling resistance due to an increase in hysteretic losses. Additionally, vibrations lessen the extent to which your tyres are in contact with the road; bouncing up and down reduces time and/or surface area of contact, which may result in slippage and thus, less efficient power transfer to the ground.
@@andrecoetze33 interesting, I was talking more about when you hammer down the power, I was wondering if a lower pressure tyre would not transfer some of the forces to the ground like a higher pressure one. But I see your points, definitely they count towards overall ride speed.
Interesting, maybe do a similar comparison between frame materials (Carbon, titanium, aluminium, steel) of similar geometry, such as the Ribble CGR frames.
This was just for cruising. Things will get more complicated when you are stumping on your pedals that will induce vertical movements that will compress and decompress the tires with each pedal cycle
Thinking about it, assuming you're not jumping on the pedals (and I do stand a lot when I'm riding: maybe I'm less efficient than I think!) if you're glued to the seat there shouldn't be any vertical movement.
Yep but a lots depends on your body weight. If you print 90kg in the scale you should run whit more the 80ps on the tires otherwise you’ll not compensate the comport and rolling resistance.
#askgcn Hi everyone at GCN megabase and in this thread. I'm converting my gravel bike from mechanical disk brakes to hydraulic brakes on the back wheel because of the poor braking performance. The front wheel brake's performance is ok. Both wheels have 140 mm discs. While converting an issue has arisen: The frame has got a Post Mount standard whereas Shimano only sells Flat Mount brake callipers for STIs. I've now got two options: Either use an adapter (if so, which one) or use an MTB Post Mount brake calliper together with the STIs (if so, do I have to pay attention to the brake outer hose)?
#askgcn Similar question: I've currently got hybrid hydro/cable brakes. They suck, and I am thinking of replacing them with cable disk brakes: what do I need to look for when sourcing new brakes?
Great video👍👍. I have done similar experimenting and have settled on 28 mm at 75 psi for a noticeable difference in ride quality with out any loss of speed. In the video you mentioned a app on your phone that you used for the testing. Wondering if you would be able to share the name of the app?
I was running my 28mm at 75psi for a while but struggling to find top end speed especially on descents. I upped the pressure to 90psi and now I am able to descend faster and overall speed has gone up. So I would say ride the highest pressure that still feels comfortable.
What are your thoughts on tire pressure and what do you use in yours?
130psi on 23mm conti gran prix amber sidewalls. it's the past & will be the future!!
@GCN Tech : How much does the rider weight?
Great information! Btw what’s the brand on that Aero road bike ? And the sunglasses on the bench? Thanks
That I have no idea what PSI transfers to a normal way one would state tyre pressure (bar, kg, pascals,...)
I use 4.3 bar at the rear and 4 bar at the front, because the roads are really bumpy where I live and I use 28mm tyres, and I only weigh 63kg so I'm not that heavy
Rough and bumpy roads. I'm a road cyclist and never ride on anything other than roads. However, finding a decent, smooth, pothole free, good condition road surface is a novelty.
So much so that if by chance I find one, I turn round and ride it in both directions.
Its not just the roads, the cycle paths are not getting maintained either.
You should come and try Swiss roads. Most are probably smoother than a velodrome 😅
@@HFields That's because you are in a country that has the foresight to invest in it's future. Here though, we simply don't. Everything on the cheap then wonder why it's broken. If it wasn't so utterly depressing it would be laughable.
Move to Florida.
Agree mate, it is the worst thing about riding in this 3rd world country as far as roads are concerned.
At age late 70s I road for years at 120 or higher on 24 with tires and it was dangerously a hard ride. I now ride at 100 and looking forward to ridding this coming year at 80.
Use the widest tire you can fit you’ll be glad you did
I love an endurance ride 150-250km on a Sunday so reduced vibration is very important with respect to rider fatigue. I’m 90kg and ride with a 28mm up front at 80psi and a 32mm out back at 70psi on Hunt Supa Dura wheels which are designed for 28-32mm tyres.
Roll well, soak up vibrations and also great grip in the wet.
28mm is a GP500 (Conti)
32mm is a 4 seasons (Conti)
In summer I ride 85psi up front and 75psi out back, it’s a bit drier on the roads and less mud etc.
Good video - just wondering if there is also a way to work out how pressure affects the risk of getting a puncture - this is an especially important consideration for those who use their bike to commute on bumpy roads!
A lower pressure will resist punctures better because the tire will conform over debris. When a tire has very high pressure and is prone to a puncture much easier. Think of it like a balloon that's half deflated it's very difficult to pierce. But a balloon blown up to its maximum is very easy to pierce.
@@rider65 too low risks your rim though. A bump could hit your rim as your tire doesn't hold hard enough against it.
Both too much pressure and too little (due to pinch flats) increases your risk of punctures on bumpy roads!
Would have been interesting to see you refine it even more, say try 70psi then go 5 either way depending on what 70 showed. Also would have been handy to know what the wheels are, so what the rim dimensions are?
100% correct. When I went from 25mm to 28mm tires, I started with a bit higher than the recommended PSI for my set up and weight, then I did the same exact ride few times a week reducing few PSI per ride (about 3 at the time) until I found the sweet spot. I went from 97/95 on my 25mm to 67/65 on my 28mm (different wheels of course). It took me few weeks, but it was definitely worth it the time and I wouldn't go back!!!
@@FRamirez1A Just curious (since you did all that work...) what you estimate your riding weight was and the quality of the roads you tested this on?
@@georgehugh3455 Just go to the ENVE or SRAM tire pressure calculator (I used the ENVE chart). Depending weight, tires size and your wheels internal measurement you can calculate a pressure to start with. I have tubeless set up and my wheels are 21mm internal and I use 28mm schwalbe. I weigh about 175lb. My local roads are in pretty good shape (obviously not like a velodrome), but you can definitely feel a difference in comfort. As a matter of fact, when I went under the sweet spot for me was SUPER COMFY, but the bike felt really slow accelerating off the saddle, so I went up in pressure a bit after that ride.
@@georgehugh3455 If you're curious to have another similar feedback, I weight 145lbs and when I switched from 25mm to 28mm Tubeless, I lowered my pressure "Front/Rear" from 90/100psi to 55/65! I always have 10lbs less in front cause 55% of the weight is at the rear as a chart I saw long ago. Roads are quite shitty in Quebec "Canada". The difference was night and day, no way I'm going back to 25mm ever!
@@PanzerIV88 Thanks :-)
Agreed. After riding at 125 psi on 23 & 25 for a dozen or more years. I did a similar exercise and the-new t/p is 25 psi lower on 25 mm tyre , improving handling and comfort immediately. Make the adjustments across on 32 & 40 with immediate results and will continue to hone in on the sweet spot for 28 , 32 & 42 mm tyres.
the guys from that rolling resistance website test on a threaded steeldrum, quite different to tarmac, where lower pressure is needed.
while I do agree in not trusting their tests compared to irl scenarios, their data is good for comparison between tires
When I went from 25mm to 28mm tires, I started with a bit higher than the recommended PSI for my set up and weight, then I did the same exact ride few times a week reducing few PSI per ride (about 3 at the time) until I found the sweet spot. I went from 97/95 on my 25mm to 67/65 on my 28mm (different wheels of course). It took me few weeks, but it was definitely worth it the time and I wouldn't go back!!!
Interesting. How much do you weigh? I'm preety heavy for a roadie 92kg and I ride on 28C Schwalbe Durano on 100psi/7bar and I never had a flat and I ride on harsh roads mostly.
@@Jurica-mtb Just go to the ENVE or SRAM tire pressure calculator (I used the ENVE chart). Depending weight, tires size and your wheels internal measurement you can calculate a pressure to start with. I have tubeless set up and my wheels are 21mm internal and I use 28mm schwalbe. I weigh about 175lb.
@@robbiddlecombe8392 my pressure isn't going to work out the same for you. I went to the ENVE pressure chart and got the recommended PSI for my set up (66 psi in my case).
Since I was use to 97/95 on my 25mm tires, I didn't want to start so low and that's how my whole test began. In every single ride I would log my pressure in STRAVA so I could compare my data at home after syncing with my bike computer.
Per ENVE Chart, if you are between 170 and 180 pounds, for 21mm internal wheel size and 28mm tires, the recommended pressure is between 66 and 69 PSI, but once again, that should be just your starting point for testing.
@@robbiddlecombe8392 I'm not really sure, I'm not an expert on wheels or anything like that, I just followed the chart and it worked for me. Are you running tubeless set up?
(When I say that it worked for me I mean that at the same watts I increased my average speed like 1 mile per hour if I recalled well).
@@robbiddlecombe8392 Yes, I run tubeless and I love them. 3 seasons with them, only 1 flat that I fixed with a plug. I don't even carry a Spare tube anymore(I did the first season that I switched to tubeless).
My understanding is that tire companies optimize side wall and tread design to operate best at 15% rim drop. For me, that's 47 psi front, 55 psi rear on 32mm tires. I was pleasantly surprised to find that this not only rode a lot smoother, but handling and stability in corners also improved vs higher pressures.
15% rim drop?
I am using the exact same pressure as you with 28mm tyre on 18mm rim. For 32mm i use 3-5psi lesser. I am 63kg. My bike feel smooth and fast and super enjoyable to ride
i like the idea to use your phone to objectively measure vibrations. about the experiment: it would be important to repeat runs with the same settings to see how consistent the results are. then it would be possible to say whether the differences are real or a statistical artifact. about too high pressure: I think that often feels fast because you feel more of the vibrations through the frame. testing wheel rolling resistance in the lab is done on a smooth surface. on a real road less pressure can be faster because the bike does less horizontal movement.
Much agreed with multiple runs and smaller pressure increments. I would also take it a step further repeat the experiment with some potholes and cobbles - those results would be interesting as well. Great work overall :)
Thanks for doing this test. Something I'm constantly changing is my tyre pressures. I'm not the fittest or youngest (51 years old) so always thought that riding with the highest psi (120 on my current tyres) would allow me to ride at my fastest and use less energy so long as I can put up with the harsher ride. I'm currently experiencing discomfort around the back of my neck and I'm guessing it's down to the harsh rides I've recently done. After watching this video I am now going to reduce my psi to 80, I totally get why you experience a faster ride with the slightly less up and down movement which is actually a lot of wasted energy.
I always run a slightly lower pressure on the front to help with grip (especially in the winter). I find my ideal balance between speed & comfort is 95 rear (as I'm a bit lardy..) and 90 at the front. However, after seeing this vid I might try 85 at the rear and 80 at the front. Really useful vid Alex! :-)
These results fall in line with my experimental experience. With both 25 and 28mm tires and 85kg of heft, I had found that 80 psi was my magic number. But after a winter and some more testing, I prefer the 75 psi. Much smoother at least and my avg mph is a bit better even! Thanks for the number crunching, Alex!
Apparently the tubeless Panaracers I've been trying to seat for the last few days think the perfect pressure is 0 bar (0 PSI) 😅
Get some latex tubes and save yourself the hassle
@@richardggeorge 1) I can't give up and 2) tubeless is great once set up. That set up can be a pain though.
You can seat nearly anything if you have a 60 gallon 240 volt air compressor in your basement. Good luck if you can do this on the road if it burps!
I added another layer of tubeless tape. Then my Panaracers seated.
Have you tried the soapy water trick? As Gary said... more tape might help. Also (if you're not already doing it), you might need a compressor or a chargeable pump.
Interesting video, illustrates the difference between a "Road Bike" and what we used to call a "Hybrid" usually used on the road or cycle tracks.The bike I normally use has suspension forks and a suspension seat post, 44mm tyres running at their rated maximum of 4.5bar. If traction is compromised for mud or ice I reduce the pressure by 1-1.5 bar. The bike then feels "soggy". No more comfortable just less agile, and harder to pedal.
Great concept for a video, I do wish with all these that the sample size went up a bit. You can always do repeat runs off-screen if it's boring, but would make the outcome so much more reliable. The 2s difference between 80 and 95 psi could easily be from a couple of windy gusts or a slightly different line taken. Taking an average of 3 would really mean something
My thoughts exactly - but this is GCN not a scientific journal! That bit when Alex was checking that the tyre was at the target pressure of 100 psi, saw it was at 95 and said "that'll do" tells you all you need to know! 🤣
Or you can do the repeat runs yourself.
I have 32cs on my hybrid bike and imo the percent spot for speed and comfort (inside and outside the trails) is between 75-85 psi (usually 85 tho).
I swiched back to 25 mm tires and 8.0 bar in latex tubes. It's way more fun than a 32 mm tire with 5 bar - no matter what the current trend says. It was such a great feeling to be back on a real road bike. Thin tires and high pressure are - in my learned opinion the fastest thing you can ride on a good road. When I want to ride my road bike I plan my routes picking the best possible roads available in the area and ejoy it. I know that low pressure will be better if the roads get worse and sometimes it can be anoying if these kind of roads cannot be avoided. But I don't want to win races. I am out there for the 8 bar on smooth concrete in narrow tires feeling. This is something you cannot get on a low pressure bike. If there is a tour on which I cannot avoid rough roads - I will use my gravel bike
I usually use 60psi on my winter tyres (32c alloy wheels) and a manufacturer recommended 80psi (28c Hunt carbon 44 wheels) . The summer tyres are definitely less comfortable but do feel quicker.
As an added bonus, tyres at lower pressures will deflate slower than tyres at high pressures.
Anecdotally, I know, but running my tubeless tyres at between 75 and 80psi, I'm not pumping them up as often as when I ran that 90psi.
That rubber band phone solution should be in 'hack or bodge'.
Don't you mean "hack forward slash bodge" ?
Yes.
Seems I've been pretty much on the sweet spot of 70psi. I'm 150lbs and run schwalbe pro One, 700 x 25 measuring 30mm on Zipp 303s tubeless
Would be glad to see if you have a video regarding this tire pressure topic during a climb. Would love to know which psi is faster. :)
I'm an 80kg rider and I've always felt comfortable riding 100 in front and 115 at the back, both wheels are 25
Anything lower than those felt uncomfortable so I can't relate to what's shown here that lower pressure equals to more comfort
I guess weight of the rider does play a huge role on this matter
Great video, GCN! Any chance we could see how the road surface and tire pressure affect bike speed when you're actually putting down effort? Might be a great opportunity for a test using an e-bike pushing a steady (x)w. Also, as someone else pointed out, an average time from 3-5 runs would help compensate for wind, slight changes in line, etc. Again, great work!
after years of riding and figuring as a 70kg rider 60psi front and 70psi rear on a 28 rubber works best for me..
My lower back has really thanked me for dropping the pressures over the past few years. Although 80psi on 20mm race tyres back in the day probably wasn't doable.
I enjoyed this - no, it's not a perfect test (more runs would help), but I like the approach. More importantly, I love Alex's new Orbea. That color scheme is beautiful.
Honestly, more data only helps him, it doesn't help us, there's just too many variables: rider weight, tire material, road surface etc. He's shown how to do the test, now we can run it for our system and location.
interesting. i notice that when I pull the track pump's nozzle off the valve then put it back in the tyre loses 5-10psi so maybe worth putting the extra in to account for this. 80-90 seems a good pressure for 28mm for most real world conditions
I think you don’t lose the pressure by taking the nozzle off, you “lose” it by putting it back on. Because the air goes from your tire back in the pump. More volume-> less pressure
I had this same issue and then I got a nice Lezyne pump with an air bleed system and then I saw I did not need to pump my tires everyday 😀
😆 Why would you put the pump back on after you’ve pumped it up?
You’re only letting the air out of the tyre to repressurise the pump chamber.
If you add more in to account for this pointless step, and then don’t do that step, your tyres will be over inflated!
@@stevenrholland because i was thinking that when u pull it out you lose pressure
@@stevenrholland when we take the pump off some times it gets kind of stuck and you hear air escape. We mistakenly would put the pump back on to check the pressure not realizing that it was only making it worse.
your test was on smooth road surface, for the roads i'm stuck with near where i live the 80 or even 75 would result real good because of less hard tire bumpiness losing efficiency. I typically run 80 rear and about 76 front.
The weight of me and my bike & the bits and bobs i carry is about +120kg, i usually run a 100-110 PSI, anything lower, it feels like I'm riding on the rims and really squidgy/squirmy on the corners.
Same here but im running 87psi using 25mm zipps, and 67psi with my 28mm mavic’s both tubeless
Yup, this tire pressure is only optimized for him and his current set up. Different tires, different weights, different surface conditions all change the equation. Only way to know what works for you is to go find a hill with like surfacing as you intend to ride on and ride it with different pressures under as close to like conditions as race day to see which is best.
Just saying … the new orbea orca aero in that silver looks amazing 🤩
GCN needs to read up on tire impedance. BicycleRollingResistance's tests and other smooth-ish drum dynamometer tests don't show the effects of tire impedance. Tire impedance is the loss of energy due to rough surfaces (that's way oversimplified). The effect impedance is that it limits how high tire pressure can go. Practically that means that as you increase tire pressure (and cRR goes down), there will come a point beyond which cRR starts to go up. That point varies from surface to surface and tire to tire. Leonard Zinn, Josh Poertner, Tom Anhalt, and others have looked into this. There's lots of data online.
Also, the comfort factor can't be overlooked, and that factor may actually be a performance-limiting factor. I'm not sure what research has looked at this, but it has been suggested that prolonged exposure to certain ranges of vibration frequencies (and likely amplitudes) can lead to earlier fatigue and may have other effects. There's likely merit to the idea that a more comfortable rider is a faster rider (I don't mean beach cruiser, big cushy seat, and upright comfy).
You guys might want to consider a test. Find a rough road and compare how riders feel over the course of and hour or three, wherein one rider rides at lowish pressure while the other rides at really high pressure (Maybe 60 or 70 psi vs 110 or 120 psi).
Thanks - was looking for a post like this (before I had to write it). I would add that typical UK/Pacific NW wet road conditions also add a slip/grip factor that improves with a reduction in pressure. Higher pressure helps avoid pinch flats for tube users, creating a practical lower limit. The right tire pressure is usually the result of a few compromises.
I ride 32mm tires at close to maximum recommended pressure, 100 psi/7 bar. I think 80 psi is only marginally more comfortable than 100, to be honest, with noticeably more rolling resistance, and at lower pressures I tend to get quite a few more punctures on our poorly maintained US roads. I also suspect, admittedly without hard evidence (no pun intended), that fully inflated tires tend to last a lot longer than ones run at lower pressures.
Lower pressure will actually decrease puncture probability not increase it. Lower pressure will allow the tire to conform over debris rather than being pierced like higher pressure tires. It's mostly down to perception. Go check out Jan Heine from bicycle quarterly, he's been doing in-depth research and Analysis on tires and pressures for over a decade. He has so much information there it'll make your head spin
Ive just got a speed bike and from my lil xp if I run on 85psi (Im 70kg) its more likely to get a flat tire when I hit medium imperfections on the road, as the tire "bites" the ground. So Im now riding with 100-110psi and I can feel it goes much easier \ô/
3:10 Hey boys, let’s make an entire video about tyre pressure. Do we need a pump for that? Naaah.
I had doubt at first bout whether tyre pressure do make a difference. I used to run 100psi all round. But when i drop it 90 -87 psi. Major difference. Smooth and stable. Also comfortable considering where i live road surface are horribly paved.
It all depends on many factors of course.
But generally with my road bike I usually start with the pressure between the max and min recommended pressure, add 5 to the front and remove 5 from the back from that, then refine from there to find the most comfortable pressure with least rolling resistance. I find this varies greatly between tires hence I didn't put a specific pressure down.
My mountain bike it's a little different, if I'm going to use it on the street then I simply run the min recommended pressure. Then off road, I find I often run well below that recommendation. Again, I didn't name a specific pressure because it varies greatly between different tires, but also the terrain really can take on an equally important role in deciding this.
Maximum and minimum pressures are nothing but liability tags. You can basically ignore them because they don't mean anything the manufacturer does not want you to run Tire lower than their minimum recommendation or higher than their maximum recommendation. It has nothing to do with performance. To find the right pressure it takes much experimentation and even more so on a mountain bike
@@rider65 little more to it then that (they have reasons from wall stiffness (tire folding onto it's self), rim protection, blow outs (more likely to happen at low pressure then high believe it or not), etc. But it would be far too much work for them then just give a general guideance.
Thank you for testing all this stuff, so we don't have to! :-) But please do this again uphill to see how much power the elastic deformation eats with each step. I guess it might be the best choice to ride 100 psi at the rear wheel and 80 psi at the front wheel at your weight.
Your tire pressure should depend on 1) The size of your tires, 2) Your weight, 3) The condition of the roads you ride on, and 4) How observant you are (whether you "ride light" or "ride heavy")
I tend to still ride with a 23 in front and a 25 in back, and both at 95 psi, ever if I've put on a "little" weight in the last 35 years.
Was going to make the same point. Lots on here concluding 80psi is the best pressure but totally dependant on tyre size and weight. For me at 85kg I go up to 105-110 in summer, good roads on 23-25 mm and high tpi cotton tyres, down to 90 winter w/25's. 80 or lower would feel a little sloppy for me at my tyre width and weight
Well I can tell you Bill that a bit of you're thinking is outdated. If anything you want the wider Tire up front for improved traction and braking. Checkout Jan Heine from bicycle quarterly and all the data on tires there is a ton of information there that will change your way of thinking.
@@rider65
Nobody who rides on pavement does that. That said, I have to say that my Mountain bike is set up that way, with a slightly wider, with more knobs, in front. Riding on pavement and dirt is completely different.
Ok, how did you run 40 without getting a puncture?
40 is what my mountain bike is at when riding on road. That's a 2.3 inch wide tire, 58.42mm.
Granted my road bike is a 23mm but I get punctures under 100psi.
I have those same tubeless tires and I use the manufacturer recommended tire pressure chart. Their recommendation are higher than my regular clincher set up.
I’m running tubeless tYres with lower pressure. Interpolating your figures it would seem that 70 psi would be the optimum tyre pressure for speed and comfort.
My understanding is that the presenter, Alex, is a big fan of tubeless and rides on them exclusively.
@@sventice as am i. In three years ive had two punctures, it was only the next day did I notice a damp patch. The last one a stan’s dart sort that out 18months ago been riding on it every since. I found the mavic tyre pressure calculator to give lower pressures than the zipp calculator. Both calculators give numbers im happy with but about 70psi is a good number for me.
Was the windspeed IDENTICAL for each trial? To do a coastdown test on a bicycle, you need to be inside a big building.
The windspeed needs to be
You are not wrong, but the fact is most people don't have an indoor hill. In lieu of that, once you feel you're in the neighborhood of where you need to be, you can start to collect more data to validate your results. If you're doing hill climbs once every week, do 3 at each pressure (12 hill climbs in one season) and at the end of the month you'll have a very good data set (12 samples at each of 4 pressures).
I think given the accuracy of the equipment, not under lab conditions, margin of error, number of tests i.e. just 1 per category etc. I don't think you can really draw definitive conclusions for a couple of seconds between 100psi and 80psi for example. I would agree that you can probably show the general trend i.e. lower psi will result in a more comfortable ride. Anyway, that criticism aside, enjoyed the video as I do all your videos. Did you have inner tubes on by the way as I know tubeless are usually on lower pressures anyway?
Are you questioning the veracity of his rubber-band mounting system?!
You're one of those science deniers aren't you!? 😉
pirelli also recommends around 75psi, depending on weight so it seems to be consistent.
I changed my 700 x 38c hybrid tyre to a 700 x 32c road tyre on my Giant Hybrid bike with front suspension forks. I had both at 80 psi and the 32c tyre is more comfortable. Maybe the 32c tyres have more tread or thicker being newer but the difference is amazing. Also the bike is faster with 32c tyres.
yes, hybrid tires are very beefy, many have thick puncture protection layers and thick hard sidewalls. they are designed to last a long time with low maintenance, and the construction is also mostly way simpler and cheaper than road bike tires. they stay harsh and wooden feeling even at very low pressures. a high end road bike tire can feel like silk against that, even at higher pressures.
I thought that the main advantage of lower tire pressures was power being more easily transferred to the rear wheel on bumpy surfaces. This could also be a good experiment to make (constant power output vs. speed vs. tire pressure).
Definitely another advantage to running lower pressure on real world roads is the larger contact patch of the tire allows you to deliver more power to the road to the point that it is a bigger difference than the added rolling resistance. GCN did a video (actually a couple I think) on this a few years ago.
I used to use about 100psi but was loud and clattery and harsh and uncomfortable on my specialised Tarmac.
I wanted to improve things.
I tried 95psi and did some out and back runs in a set time recorded the ave wattage.
I dropped to 85psi and repeated runs. Did the math.
I saved 3.5% power with the 85psi. This was 7.6watts saving. I was about 90kg. Bike is about 8kg.
So, overinflated tyres bounce over bumps, reducing speed, and underinflated ones are too slow. No s***, Sherlock!
When I was an audiophile, I found people believed wires made all the difference and would buy 20,000 $/€/£ speaker cable sets. Then I turned to photography. They're still debating an arcane "equivalent aperture" concept and buying 20,000 $/€/£ lenses to have the maximum aperture. Now I'm a cyclist. The same gullibility, with people ready to believe wider tyres are faster. Is there a hobby where they don't throw a lot of BS at your face? If there is, please let me know.
(In the meantime I swapped the 700x35 tyres on my hybrid bike for a 700x32 set of tyres. Although I could easily believe my bicycle became slower due to the extra narrowness, the fact that I keep taking time off my rides' duration tells me otherwise.)
I pick a stretch of the road I am going to ride, and start with tires pumped up obviously too hard, and repeat that stretch with lower pressures until I just barely feel the road. That gives enough pressure to protect the rims and not have any squirm. Any lower doesn't improve anything for me.
Very useful video. Thanks mate.
i’ve forgot, but isn’t it around 80psi for road race and 60 for mtb..
i like them tight, and if they feel slippery you can always release the pressure for a millisecond
7 BAR back, 6.5 BAR front, perfection.
Interesting Alex, what about the benefits to rolling resistance of tubeless, and the fact that hookless rims tend to have a maximum pressure of 70psi, and that nobody recommends running 28mm tyres at 100psi anymore?
All the recent rolling resistance findings seem to be that super flat tarmac benefits higher pressures, but typical UK roads would benefit from lower pressures. Your test was on a descent as well, so pedalling over deformations in the road would have shown a difference I think? Vibrations feel fast, but aren't is often the thinking.
Having watched this, I'm planning on upping from 70 to 80 psi and trying to take the smoothest path on the road - running GP5000 TL 28mms on Hunt hooked rims. Thoughts? (anyone)
Psi= factor in Roads + Rider weight +Tire width+ season
+ Tyre suppleness/compound (320 tpi better than 60tpi for example,)
@@richardggeorge i also factor in just what I like... my perfect comfort/ feeling fast mix. Dont really care if lower is theoretically faster if I then feel like I just ate a whole cheesecake...
Awesome experiment, i really enjoyed it.
On both my old bike and the new one the pressure inscripted on tires was 3bars. Continental and Maxxis 2.2 and 2.1 . Problem is at 3 bars it becomes extremely hard! At 2.7 is still very hard, 2.2 seems to be appropiate. I wonder if 3bars is the maximum allowed or the recommended...
Question: The "SRAM tire pressue guide" calculator suggests pressure of around or even below 2 bar (down to 1,66 bar) for my use-case of a 50-584 tyre (Continental Contact Urban). However, the manufacturer specifies 2,5-5,0 bar pressure. Can I nevertheless set the pressure (much) lower than 2,5 bar to match the SRAM values? What can happen if I stay below manufacturer's recommendations? Any experience?
It’s funny no one ever addresses the possibility of pinch flats or rim damage. Just speed and comfort. How fast and comfortable are you sitting at the side of the road fixing a flat. 100psi for me
Exactly. In 30 years of riding, 110 psi is my sweet spot where I won't bottom out and hit the rim.
@@huffytoss That’s a awesome user name ! I’ve tossed a couple Huffys in my life !
They’re tubeless mate. You can run at 40 psi and won’t get a puncture. Cannot get pinch flats with tubeless. Been running them for years
@@DigitalB11 you can still bottom out the tire and damage the rim with tubeless.
@@DigitalB11 have you ever broken the seal between the tire and rim because of low pressure? Thanks
Okay, I had an old Bianchi with 23's, top pressure was 110 PSI, now I've got a new bike with 32's, top pressure 80 PSI. If I remember correctly, I'd ride the Bianchi at 100 PSI, and I ride the new bike with 70 PSI
What handlebar is that? It does not look like the standard two-piece stem and bar Orbea offers on the Orca Aero. Were any modifications needed to run that integrated bar?
Can you tell if riding 25 mm tyres at 80 at the front and 85 at the back, I am 71 kilos or going for wider tires at a lower pressure would make that much difference to my shoulders, I have just had double shoulder replacement and all my bikes can only take 25 mm tyres and I don't have much money, I have a Dawes Galaxy which can take bigger tires but is heavier, not sure what to do x
I have Vitorria 28mm tyres but the side wall says the pressure range starts at 87psi. Is it safe to inflate under this minimal limit? Do others pay much attention to the side wall recommendations?
Would the results be less significant for lighter riders and slower riders? ie the vibration loss isn't worth the gain in friction. I'm 60-62kg and a new rider so i'm down in the 25-30km/hr still, riding an entry level road bike with tubed tires at 100 psi.
What about tire (I'm in the US) wear? Wouldn't tires at lower pressure wear faster?
I've been running 80 PSI since I switched to tubeless and I was actually thinking about dropping that down to 70 now that I'm going back to 28's, but 80 seems to be about right
I mean honestly go as low as you can before the tire impact the rim on bumps and potholes 80 psi maybe optimal but it's really perception. There is a Tipping Point between the very lowest and very high pressures for optimal traction and performance. It may be 70 but you have to experiment it may be somewhere in between.
Im a 75kg rider and 9kg alu bike 25c gp5000. 60 front 70 rear feels comfortable but isn't too low?
Does freewheeling count less than contact time with the tarmac? I thought lower tyre pressures allowed more contact time when pedalling hence more efficient use of power, we have all experienced bouncing with higher pressures.
Comfort=Vertical displacement=Losses
Ergo, I don't think comfort and efficiency are necessarily in opposition to each other.
Thx i have the same pressure gauge and learned about the release valve on the side 😂
So it appeara that 80 psi, or roughly 5.5 bar should be the quickest in terms of rolling resistance. What about hookless rims then, since the maximum pressure they are allowed is 5 bar?
interesting vid... just curious on your body weight and bike size to adjust to my own size. i run a tcr m/l frame and weigh 178lbs at 85 psi. just throwing that info out there
Let's not be obsessed with accuracy here...
First off, it's not as high as you might think. - The pressure gauge has a error margin, as do your phone sensors, etc. Changing your tire temperature by around 12 degrees C (difference between when you set off and a few minutes of riding or moving from shade into sunlight) will result in a 5% change in pressure. Tires are not the only thing suppressing vibrations. What about the stiffness of the frame, fork, stem, handlebar, wheel profile etc. Soooo many dynamic variables - none of them sadly mentioned :-/
Secondly, as noted at 1:03 the difference between a 100 and a 120 psi tire is 1W, for 100 vs 105 it will be about a quarter of that - not sure what to compare it with... Possibly trimming your nails?
A new cyclist might watch this and think they need to get their pressures right up to a single psi, which is just silly. Literally all you really need to do is follow the tire manufacturer guidelines and you're good. Pirelli recommends 80psi for the 28mm P Zero TLRs for a rider between 76-85kg. - Which is exactly the result that Alex got. Shocking, huh? A little disclaimer at the end about that would be good.
Highly informative. Much obliged for your good work here. Stunning to see a quicker ride at 80 psi than 100. There are more things in heaven and earth, Horacio, than are dreamt of in your philosophy, as your fine countryman has it.
Is it true that higher pressures deter flats? I run about 90-100 on my road bike. With tubes.
Doesn't it affect the puncture resistance of the tire when running too low or too high tire pressure?
Do you think that there are any discrepancies in results if you add other dependent factors such as temperature?
Is it the same for tires with an inntertube?
It's different for every rider, every road surface, and every tire. You know the methodology, now you have to go run the test yourself.
I think the sweet spot is below 80 psi. Even if the speed is slightly slower under this test condition, it cannot be mapped to normal riding. This is because vibrations that are not absorbed by the tire have to be absorbed by the person riding the bike, in the muscles etc. So the vibrations not absorbed in the tire are tiring(!) (lol) your muscles and as a result make you slower on a longer tour. This has to be factored in, and as a result the OVERALL sweet spot is somewhere below the "seemingly optimum" tire pressure under the academic test conditions not factoring in this effect.
Now do the same test going uphill.
so 80psi is the sweet spot on your results....
Yet Hookless systems can only run a maximum pressure of 72.5psi 😂 priceless
My thoughts exactly, but i warched the video 10 hours after it was posted.
Dan C, thank you for bringing this point up.....I still run "hooked" rims(Roval CLX 50's), I weigh 160LBS, Conti's5000TL's 28, front at 60/rear 65
@@hkremer3234 yes I'm on hooked aswel some camy boras. personally I'm not a fan of hookless.
All it really benefits is the manufacturer in cheaper production costs. the watt savings for the customer are so small it's probably not even worth mentioning
@@danc1829 Also, ask any reputable wheel builder, hookles rims lose spoke tension much faster than hooked rims do.
It takes energy’s to vibrate your body.. that is energy that‘s being taken away from bike moving forward!
Vibration losses are minimized by lower pressures (energy lost from vibrating rider and bike).. rolling resistance losses (from bending tire carcass) are minimized with higher pressures.. therefore, for each tire on a given surface there will be an OPTIMUM pressure.. higher is not better.
Most rolling resistance tests don’t take into account a rider sitting on bike sopping up vibration and bleeding away from forward motion in form of heat into environment. VeloNews and WheelEnergy did a test where they used a textured rollers and an air shock as a stand-in for a rider and demonstrated these vibration losses (compressing air shock likewise bleeds off energy as heat) though not as much as a rider likely would!
. Temperature and speed of the tires will also have a slight pressure reading. My enjoyable tire pressure 70 psi.. Enjoy your ride.
I'm not sure if we can assume that a lower pressure is faster overall. In this test it was faster going downhill without pedalling, but would the higher inflated tyre transmit more power to the ground when pedalling and be overall faster?
No, literally the exact opposite. Unless you are biking on a glassy-smooth surface, very high tyre pressures increase rolling resistance due to an increase in hysteretic losses. Additionally, vibrations lessen the extent to which your tyres are in contact with the road; bouncing up and down reduces time and/or surface area of contact, which may result in slippage and thus, less efficient power transfer to the ground.
@@andrecoetze33 interesting, I was talking more about when you hammer down the power, I was wondering if a lower pressure tyre would not transfer some of the forces to the ground like a higher pressure one. But I see your points, definitely they count towards overall ride speed.
Interesting, maybe do a similar comparison between frame materials (Carbon, titanium, aluminium, steel) of similar geometry, such as the Ribble CGR frames.
I ride with 110psi on tube tires, whats the equivalent for tubeless tires?
Is it the same with tubes as tubeless?
Awesome Alex, thank u sir!
i think pirelli provides rec tire pressure, and it differs for diff rider weight. i use their chart per tire. nice vid!
This was just for cruising. Things will get more complicated when you are stumping on your pedals that will induce vertical movements that will compress and decompress the tires with each pedal cycle
Ya. Same test but with a power meter?
Thinking about it, assuming you're not jumping on the pedals (and I do stand a lot when I'm riding: maybe I'm less efficient than I think!) if you're glued to the seat there shouldn't be any vertical movement.
Thanks! Great video! I’m definitely going to drop mine a tad.
Is the pro peloton using wider tires now? Still 25s?
Could you give the pressure values in stones per square cubits please?🤔
Higher pressure reduces pinch punctures i reckon, in Thailand where i cycle you can hit an unexpected pothole
Yep but a lots depends on your body weight. If you print 90kg in the scale you should run whit more the 80ps on the tires otherwise you’ll not compensate the comport and rolling resistance.
#askgcn Hi everyone at GCN megabase and in this thread. I'm converting my gravel bike from mechanical disk brakes to hydraulic brakes on the back wheel because of the poor braking performance. The front wheel brake's performance is ok. Both wheels have 140 mm discs.
While converting an issue has arisen: The frame has got a Post Mount standard whereas Shimano only sells Flat Mount brake callipers for STIs. I've now got two options: Either use an adapter (if so, which one) or use an MTB Post Mount brake calliper together with the STIs (if so, do I have to pay attention to the brake outer hose)?
#askgcn Similar question: I've currently got hybrid hydro/cable brakes. They suck, and I am thinking of replacing them with cable disk brakes: what do I need to look for when sourcing new brakes?
Does tire pressure have any affect in crashes due to Cracks and potholes on the road?
Great video👍👍. I have done similar experimenting and have settled on 28 mm at 75 psi for a noticeable difference in ride quality with out any loss of speed. In the video you mentioned a app on your phone that you used for the testing. Wondering if you would be able to share the name of the app?
I was running my 28mm at 75psi for a while but struggling to find top end speed especially on descents. I upped the pressure to 90psi and now I am able to descend faster and overall speed has gone up. So I would say ride the highest pressure that still feels comfortable.
On the first run the camera motorbike was in front of you which would affect the result.
Interesting. I have to di that experiment myself when the snow has gone.