Tyre Width / pressure - Marketing bilge?
Discussion
Rather than hijack the 'what road tyre thread' that is running i thought id start a new one.
On that thread the merits of tyre width have been brought up. SO on that note...
On loops i rode regularly, i noticed no difference with wider tyres, so back in 2018 I conducted i (failry unscientific) test re tyre pressures and sizes. I used 25mm and 28mm Open Pave (clinchers) and various pressures (but the same for both width tyres)
I was able to use a local hill and use gravity to roll round the corner without having pedaling affect the results A handily placed fence post on the hill meant the start postiion was always constant.
3 runs on 3 diff pressures then swapped tyres so the same wheels were used. Weather was constant with a light breeze.
Result : All over the shop, absolutuley no correlation in distance travelled to pressure or tyre size. Some runs were hugely different in distance to others. the fartherst the bike travelled was on 2 runs of almost exact distance. one 25mm the other 28mm both at the highest pressure i used.
Conclusion: It looks like marketing rubbish (which is hardly a shocker is it) . In the real world on tarmac roads it (as i already suspected) makes bugger all difference. The exception being comfort, the larger tyres are def slightly more comfortable. I suspect the unpredicatable nature of riding outdoors and not glass smooth tarmac scrubs any benefits seen in lab conditions.
Im sure some will perhapscall me a liar or an unbeliever but those were my findings in a real orld situation as opposed to a wheel on a steel drum.
Anyway, there you go. I thought some of you might be interested.
On that thread the merits of tyre width have been brought up. SO on that note...
On loops i rode regularly, i noticed no difference with wider tyres, so back in 2018 I conducted i (failry unscientific) test re tyre pressures and sizes. I used 25mm and 28mm Open Pave (clinchers) and various pressures (but the same for both width tyres)
I was able to use a local hill and use gravity to roll round the corner without having pedaling affect the results A handily placed fence post on the hill meant the start postiion was always constant.
3 runs on 3 diff pressures then swapped tyres so the same wheels were used. Weather was constant with a light breeze.
Result : All over the shop, absolutuley no correlation in distance travelled to pressure or tyre size. Some runs were hugely different in distance to others. the fartherst the bike travelled was on 2 runs of almost exact distance. one 25mm the other 28mm both at the highest pressure i used.
Conclusion: It looks like marketing rubbish (which is hardly a shocker is it) . In the real world on tarmac roads it (as i already suspected) makes bugger all difference. The exception being comfort, the larger tyres are def slightly more comfortable. I suspect the unpredicatable nature of riding outdoors and not glass smooth tarmac scrubs any benefits seen in lab conditions.
Im sure some will perhapscall me a liar or an unbeliever but those were my findings in a real orld situation as opposed to a wheel on a steel drum.
Anyway, there you go. I thought some of you might be interested.
What was the surface like?
The also unscientific attempts on this topic were for gravel bikes. The range of size and pressures was perhaps wider spread than your trial.
It makes sense if you are covering rougher ground, if the tyre can deform around the obstacle and then no energy is wasted lifting the bike up and over the obstacle. Some energy to deform the tyre, but presumably less than lifting you and the bike.
To get that deformation you need the wider tyres and appropriate pressures.
I think to see a difference maybe trying 25mm at 90psi and 35mm at 45psi maybe? Both would need to be slick or the same type of tread.
The also unscientific attempts on this topic were for gravel bikes. The range of size and pressures was perhaps wider spread than your trial.
It makes sense if you are covering rougher ground, if the tyre can deform around the obstacle and then no energy is wasted lifting the bike up and over the obstacle. Some energy to deform the tyre, but presumably less than lifting you and the bike.
To get that deformation you need the wider tyres and appropriate pressures.
I think to see a difference maybe trying 25mm at 90psi and 35mm at 45psi maybe? Both would need to be slick or the same type of tread.
neilr said:
Rather than hijack the 'what road tyre thread' that is running i thought id start a new one.
On that thread the merits of tyre width have been brought up. SO on that note...
On loops i rode regularly, i noticed no difference with wider tyres, so back in 2018 I conducted i (failry unscientific) test re tyre pressures and sizes. I used 25mm and 28mm Open Pave (clinchers) and various pressures (but the same for both width tyres)
I was able to use a local hill and use gravity to roll round the corner without having pedaling affect the results A handily placed fence post on the hill meant the start postiion was always constant.
3 runs on 3 diff pressures then swapped tyres so the same wheels were used. Weather was constant with a light breeze.
Result : All over the shop, absolutuley no correlation in distance travelled to pressure or tyre size. Some runs were hugely different in distance to others. the fartherst the bike travelled was on 2 runs of almost exact distance. one 25mm the other 28mm both at the highest pressure i used.
Conclusion: It looks like marketing rubbish (which is hardly a shocker is it) . In the real world on tarmac roads it (as i already suspected) makes bugger all difference. The exception being comfort, the larger tyres are def slightly more comfortable. I suspect the unpredicatable nature of riding outdoors and not glass smooth tarmac scrubs any benefits seen in lab conditions.
Im sure some will perhapscall me a liar or an unbeliever but those were my findings in a real orld situation as opposed to a wheel on a steel drum.
Anyway, there you go. I thought some of you might be interested.
If you did the test on 1 setup, say 10 times, and then tell us your results... that gives us an indication of how repeatable your test is.On that thread the merits of tyre width have been brought up. SO on that note...
On loops i rode regularly, i noticed no difference with wider tyres, so back in 2018 I conducted i (failry unscientific) test re tyre pressures and sizes. I used 25mm and 28mm Open Pave (clinchers) and various pressures (but the same for both width tyres)
I was able to use a local hill and use gravity to roll round the corner without having pedaling affect the results A handily placed fence post on the hill meant the start postiion was always constant.
3 runs on 3 diff pressures then swapped tyres so the same wheels were used. Weather was constant with a light breeze.
Result : All over the shop, absolutuley no correlation in distance travelled to pressure or tyre size. Some runs were hugely different in distance to others. the fartherst the bike travelled was on 2 runs of almost exact distance. one 25mm the other 28mm both at the highest pressure i used.
Conclusion: It looks like marketing rubbish (which is hardly a shocker is it) . In the real world on tarmac roads it (as i already suspected) makes bugger all difference. The exception being comfort, the larger tyres are def slightly more comfortable. I suspect the unpredicatable nature of riding outdoors and not glass smooth tarmac scrubs any benefits seen in lab conditions.
Im sure some will perhapscall me a liar or an unbeliever but those were my findings in a real orld situation as opposed to a wheel on a steel drum.
Anyway, there you go. I thought some of you might be interested.
I'll bite. Post up your exact methodology, paying close attention to dependent & independent variables and calling out your controls.
Alternatively: unscientific experiment in "fails to produce results of any value" shocker.
My personal unscientific results, as measured by my legs, tell me that hard skinny tyres are much easier to pedal on tarmac than thick soft ones. And that thick soft ones are much better than skinny hard ones when you're hammering it down loose MTB tracks.
Alternatively: unscientific experiment in "fails to produce results of any value" shocker.
My personal unscientific results, as measured by my legs, tell me that hard skinny tyres are much easier to pedal on tarmac than thick soft ones. And that thick soft ones are much better than skinny hard ones when you're hammering it down loose MTB tracks.
Listened to a podcast a while ago that was an interview with the guy that now owns Silca tools, think he was an engineer at Zipp previously. they did loads of work with one of the top Classics teams, and the gist of it was that on the cobbles, the fastest pressure was the lowest they could run without getting pinch flats (about 60psi IIRC). They did testing on perfect, brand new smooth tarmac and found that 110psi was ideal but if you went higher than that the rolling resistance would start to increase again.
Interesting re Zipp and testing on cobbles.
TBF i did say it was unscientific but it was a real world test on a road that is typical of what i ride on.
I guess my take away from it was the difference in the real world for a very average rider like myself is at best negligable or quite possibly non-existant.
No i didnt repeat each run , i just did it once each, it was bloody cold and that as enough for me lol. I understand what your trying to say about repeatable results, but i wasnt looking to do enough testing to write a paper on it
Same stretch of tarmac road
Same rider
No pedaling
Same position
Same bike
Same wheelset
Same pump used to inflate
No braking
The wildy differing results showed (at least to me) that in a real world situation that its not a big increase in performance (or no increase).
I was pretty suprised at the results i got though.
TBF i did say it was unscientific but it was a real world test on a road that is typical of what i ride on.
I guess my take away from it was the difference in the real world for a very average rider like myself is at best negligable or quite possibly non-existant.
No i didnt repeat each run , i just did it once each, it was bloody cold and that as enough for me lol. I understand what your trying to say about repeatable results, but i wasnt looking to do enough testing to write a paper on it
Same stretch of tarmac road
Same rider
No pedaling
Same position
Same bike
Same wheelset
Same pump used to inflate
No braking
The wildy differing results showed (at least to me) that in a real world situation that its not a big increase in performance (or no increase).
I was pretty suprised at the results i got though.
I remember reading a site that had apparently carried out laboratory tests of rolling resistance and then applied these to the road. I don't remember where it was...but the TL:DR seemed to be:
At the same pressures a 28mm tyre gives fractionally lower rolling resistance than a 23mm tyre but is less comfortable.
You can lower the pressure in the 28mm tyre and get the same rolling resistance as the 23mm tyre but with better grip and a less fatiguing ride.
The improvements in grip and reduced fatigue aren't much, but they're generally more significant that the trade-off in rolling resistance.
All assuming all other factors to be equal. ISTR the differences were miniscule between 25mm and 28mm, but a little bigger between 23mm and 25mm.
For us normal folk the ability of older frames to take wider rims and tyres, and/or the continuing availability of narrower rims, are going to be bigger influences than the out-and-out performance advantages/disadvantages.
At the same pressures a 28mm tyre gives fractionally lower rolling resistance than a 23mm tyre but is less comfortable.
You can lower the pressure in the 28mm tyre and get the same rolling resistance as the 23mm tyre but with better grip and a less fatiguing ride.
The improvements in grip and reduced fatigue aren't much, but they're generally more significant that the trade-off in rolling resistance.
All assuming all other factors to be equal. ISTR the differences were miniscule between 25mm and 28mm, but a little bigger between 23mm and 25mm.
For us normal folk the ability of older frames to take wider rims and tyres, and/or the continuing availability of narrower rims, are going to be bigger influences than the out-and-out performance advantages/disadvantages.
28mm, hookless setup at 70psi on a wide 25mm internal rim is considerably more comfortable than 100psi 25mm tubes on say a 21mm internal.
So thats good enough for me because its an enjoyable experience rather than a bone jarring one
Cannot notice the aero difference between my expensive Firecrests or my stock dt swiss aluminium rims. Im sure if i were any good I could reap the aero advantage
So thats good enough for me because its an enjoyable experience rather than a bone jarring one
Cannot notice the aero difference between my expensive Firecrests or my stock dt swiss aluminium rims. Im sure if i were any good I could reap the aero advantage
IroningMan said:
For us normal folk the ability of older frames to take wider rims and tyres, and/or the continuing availability of narrower rims, are going to be bigger influences than the out-and-out performance advantages/disadvantages.
snobetter said:
I thought that was the whole point? The rolling resistance difference is so negligible your better off having a less jarring ride which is less tiring / more pleasant.
yeah, I actually find the comfort difference massive, with some marginal grip improvement too. I can't get hung up on rolling resistance to be honest. I get why you might give it more thought if you're racing and a few saved Watts during a race could make the difference between winning a spring and not. But I'm nowhere near fast enough to worry about 'marginal gains'.
I just want to enjoy riding my bike so if a few wasted Watts is the cost of better comfort and grip it's a price I'll pay. I've found tyres I'm happy with (Continental GP 4 Seasons or GP 4000SII) and so I fit them and adjust the pressures in them until my buttocks are happy. I do worry that the trend for wider rims will make it more difficult to replace narrower rims on my older bikes, although I presume a wheelbuilder should be able to produce what I want/need.
But yes, I think a lot of bicycle industry marketing is either absolute bilge or it makes such small differences to 'Mr Average' riders like me that performance improvements would be negligible in real world conditions. Don't get me wrong, if I had the cash to be flash I'd be a fully paid up member of the "latest and greatest tech fanclub", but none of my bikes is particularly new, nor are any of them brimming with what you'd have called the "latest tech" when they were new. My road bike may be light weight and carbon fibre, but it's on rim brakes and QR skewers just the same as the 1990s steel bike I'm supposed to be recommissioning. I like the idea of high tech bits and bobs, but I'll let other people do the early adopting and then I'll buy into it when it has been tried, tested, and the price has come down a bit...
I just want to enjoy riding my bike so if a few wasted Watts is the cost of better comfort and grip it's a price I'll pay. I've found tyres I'm happy with (Continental GP 4 Seasons or GP 4000SII) and so I fit them and adjust the pressures in them until my buttocks are happy. I do worry that the trend for wider rims will make it more difficult to replace narrower rims on my older bikes, although I presume a wheelbuilder should be able to produce what I want/need.
But yes, I think a lot of bicycle industry marketing is either absolute bilge or it makes such small differences to 'Mr Average' riders like me that performance improvements would be negligible in real world conditions. Don't get me wrong, if I had the cash to be flash I'd be a fully paid up member of the "latest and greatest tech fanclub", but none of my bikes is particularly new, nor are any of them brimming with what you'd have called the "latest tech" when they were new. My road bike may be light weight and carbon fibre, but it's on rim brakes and QR skewers just the same as the 1990s steel bike I'm supposed to be recommissioning. I like the idea of high tech bits and bobs, but I'll let other people do the early adopting and then I'll buy into it when it has been tried, tested, and the price has come down a bit...
There's definitely a bit of divergence occuring between the peloton and "sport bike" buyers.
Chris Froome recently and many other pros in the past have issues with disc brakes, but they are being pushed by manufacturers because of buyer demand.
Tubes have always been a bit separate because not many people run tubulars, but as most new bikes don't come set up, its a choice to go TL rather than forced.
Aero definitely not important for most, and still a big deal. have to confess thats a look based decision for me
https://www.aero-coach.co.uk/time-trial-rolling-re...
Real world tests with wind and the like are not going to show you single figure watt differences very obviously.
On my TT bike I did generally attempt to get the very fastest combo I could, because events decided by seconds very common. I actually remember tying someone for the win in a 25 mile TT! But on road, comfort/feel and not puncturing more important (within reason) to me.
The difference between almost anything in cycling is tiny. Hence I called out that utter b
ks Ares posted about his F12 being 20% faster than his F8 or whatever it was. It's just fiction and confirmation bias attached to spending a load of money on nothing more than a new paintjob very often
Real world tests with wind and the like are not going to show you single figure watt differences very obviously.
On my TT bike I did generally attempt to get the very fastest combo I could, because events decided by seconds very common. I actually remember tying someone for the win in a 25 mile TT! But on road, comfort/feel and not puncturing more important (within reason) to me.
The difference between almost anything in cycling is tiny. Hence I called out that utter b
ks Ares posted about his F12 being 20% faster than his F8 or whatever it was. It's just fiction and confirmation bias attached to spending a load of money on nothing more than a new paintjob very oftenEdited by okgo on Thursday 4th March 13:44
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