RecordAceFromNew
Swinging Member
- Location
- West London
Glad to be of some help folks. To give credit where credit is due, the original work was done by Frank Berto of The Dancing Chain fame.
Need advice on 23c Tyre pressure !
- Thread starter atlantis
- Start date
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Glad to be of some help folks. To give credit where credit is due, the original work was done by Frank Berto of The Dancing Chain fame.
Wow a great response ! thanks
So can i safely say, that I have not damaged the rim or tires ?
I would really appreciate all the input I could get !
I have not ridden the bike after overinflating, although the bike held the 145 psi for approx 10-15 minutes.(stationery)
rgds
So can i safely say, that I have not damaged the rim or tires ?
I would really appreciate all the input I could get !
I have not ridden the bike after overinflating, although the bike held the 145 psi for approx 10-15 minutes.(stationery)
rgds
I'll bet my bike that you definitely won't have damaged the rims or tires. Is that reassuring enough? 
Here's a tire pressure calculator based on the advice in that article (i.e. 15% deflection). I usually go around 85 front 110 rear based on 25mm gatorskins and the 45/55 split. Seems to be quite comfortable and I've never had a pinch flat yet. Thorns are another matter though.
Here's a tire pressure calculator based on the advice in that article (i.e. 15% deflection). I usually go around 85 front 110 rear based on 25mm gatorskins and the 45/55 split. Seems to be quite comfortable and I've never had a pinch flat yet. Thorns are another matter though.
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
Sorry, but I think the numbers generated by the graph in that article are absolute piffle! 
The numbers for me work out at about 120 psi front and 145 psi rear! I once tried 105 psi front and 125 psi rear and had to stop after 5 minutes to let air out of my tyres because they were unbearable to ride on local bumpy roads at even those pressures.
I usually put only about 85-90 psi in the front and 95-100 in the rear but for a forum ride on Sunday I put about 95 psi front and 105 psi rear and found the extra pressure made the bike far less comfortable. I'll go back to my normal pressures for the next ride.
I spoke to a former pro-team mechanic about the subject of tyre pressures and he told me that almost everyone insists on using higher pressures than they probably should and no amount of talking to them would convince them otherwise. In my experience, that is true. One of my friends even insisted on putting 100 psi into a chunky MTB tyre. He learned his lesson the hard way when it blew off the rim on a descent ... (Mind you, he probably still puts 80 psi into a tyre rated at 55-60!)
People talk about the comfort of steel framed bikes, and the harshness of stiff aluminium bikes. I can make my steel-framed Basso horribly harsh by putting too much air in the tyres, and my aluminium-framed Cannondale a sweet ride by using lower pressures.
I say forget the graphs and what numbers other people recommend - just try different pressures for yourself and ride whatever suits you best. The bottom limit is when the tyre squirms about or you get lots of pinch punctures. The upper limit is what is safe. Somewhere in between is what you need and only you can decide where that is.
I definitely agree that the rear tyre needs more pressure than the front but a 10-15 psi difference is enough for me.
The numbers for me work out at about 120 psi front and 145 psi rear! I once tried 105 psi front and 125 psi rear and had to stop after 5 minutes to let air out of my tyres because they were unbearable to ride on local bumpy roads at even those pressures.
I usually put only about 85-90 psi in the front and 95-100 in the rear but for a forum ride on Sunday I put about 95 psi front and 105 psi rear and found the extra pressure made the bike far less comfortable. I'll go back to my normal pressures for the next ride.
I spoke to a former pro-team mechanic about the subject of tyre pressures and he told me that almost everyone insists on using higher pressures than they probably should and no amount of talking to them would convince them otherwise. In my experience, that is true. One of my friends even insisted on putting 100 psi into a chunky MTB tyre. He learned his lesson the hard way when it blew off the rim on a descent ... (Mind you, he probably still puts 80 psi into a tyre rated at 55-60!)
People talk about the comfort of steel framed bikes, and the harshness of stiff aluminium bikes. I can make my steel-framed Basso horribly harsh by putting too much air in the tyres, and my aluminium-framed Cannondale a sweet ride by using lower pressures.
I say forget the graphs and what numbers other people recommend - just try different pressures for yourself and ride whatever suits you best. The bottom limit is when the tyre squirms about or you get lots of pinch punctures. The upper limit is what is safe. Somewhere in between is what you need and only you can decide where that is.
I definitely agree that the rear tyre needs more pressure than the front but a 10-15 psi difference is enough for me.
RecordAceFromNew
Swinging Member
- Location
- West London
Sorry, but I think the numbers generated by the graph in that article are absolute piffle!
The numbers for me work out at about 120 psi front and 145 psi rear! I once tried 105 psi front and 125 psi rear and had to stop after 5 minutes to let air out of my tyres because they were unbearable to ride on local bumpy roads at even those pressures.
I think the graph is not suggesting that such pressure for such width is what one should use for comfort, in fact quite the opposite as you found based on the text. The question is whether the lower pressure you were using was providing efficiency and effectiveness as designed.
I think the theory is that under-inflating a narrow tyre will give rise to a long contact patch in the direction of the travel, which gives rise to high deformation loss as well as increased likelihood for pinch flats. Perhaps a wider tyre at the same pressure may have been more efficient albeit likely heavier as well as offering comfort?
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
The thing is, cyclists are human beings not machines! Vibration transmitted though very hard tyres can induce a lot fatigue on long rides so even if 5% more of your energy is being transformed into motion, you haven't gained anything if you have lost 20% of your strength because you've been battered!
I suffer from vibration-induced cramps in my feet and unpleasant tingling in my hands. It can get so bad that I have to dismount and stretch for a couple of minutes. That certainly doesn't help my eficiency. A few psi reduction in tyre pressures and I'm okay.
I preferred riding 25C tyres but for a while it was impossible to get hold of Krylions (my tyre of choice) in that size so I bought up a job lot of 23Cs. I have to use them now because 25Cs won't fit under the Crud Roadracer mudguards that I now have on my bike.
RecordAceFromNew
Swinging Member
- Location
- West London
Perhaps most of us are conditioned to run tyres too narrow for our own good - I still run a pair of 20c myself!
MacB
Lover of things that come in 3's
- Location
- Farnborough, Hampshire
that's what I took from these articles and tables but I already run wide enough tyres anyway. The real surprise was just how big a differential front to rear is suggested.
swee'pea99
Squire
I was certainly surprised by that. But I was at least as surprised by "the five fastest tyres tested were between 24mm and 37mm." The idea that a 30+ tyre can actually be faster than, say, a 23mm, is - to me at least - totally counter-intuitive.
MacB
Lover of things that come in 3's
- Location
- Farnborough, Hampshire
[quote name='swee'pea99' timestamp='1309355999' post='1727205']
I was certainly surprised by that. But I was at least as surprised by "the five fastest tyres tested were between 24mm and 37mm." The idea that a 30+ tyre can actually be faster than, say, a 23mm, is - to me at least - totally counter-intuitive.
[/quote]
I agree, I fitted some new 622-42 Marathon Supreme tyres about a week ago and they've been quicker than the M+ tyres in 700x32 and 700x35, though they are lighter than either of those.
I was certainly surprised by that. But I was at least as surprised by "the five fastest tyres tested were between 24mm and 37mm." The idea that a 30+ tyre can actually be faster than, say, a 23mm, is - to me at least - totally counter-intuitive.
[/quote]
I agree, I fitted some new 622-42 Marathon Supreme tyres about a week ago and they've been quicker than the M+ tyres in 700x32 and 700x35, though they are lighter than either of those.
srw
It's a bit more complicated than that...
One of the links in this thread led me to these two:
http://www.rivbike.com/images/static/upload/rivbike_pick_a_tire.pdf
http://yarchive.net/bike/tire_pressure.html
The first suggests a wide variety of parameters, and supports 100-110psi in both wheels for heavier riders if speed is of interest.
The second - a Jobst Brandt article - points out that the 60/40 "rule" is based on flat roads only; hills are rather different.
I'll point out that the measured pressure to which you inflate your tyres is only valid at the point of measurement. In my experience it's easy to lose 5psi as you whip the pump off the valve. And during the course of a day all tyres lose air. My Brompton goes from 95psi to 80psi over the course of a week. During a recent three-day ride my road tyres (25mm) got down to 90psi in the course of each day, having started at 120psi. And I mistakenly took them to 140psi before the start of day 1 without any noticeable difference in handling or harshness.
http://www.rivbike.com/images/static/upload/rivbike_pick_a_tire.pdf
http://yarchive.net/bike/tire_pressure.html
The first suggests a wide variety of parameters, and supports 100-110psi in both wheels for heavier riders if speed is of interest.
The second - a Jobst Brandt article - points out that the 60/40 "rule" is based on flat roads only; hills are rather different.
I'll point out that the measured pressure to which you inflate your tyres is only valid at the point of measurement. In my experience it's easy to lose 5psi as you whip the pump off the valve. And during the course of a day all tyres lose air. My Brompton goes from 95psi to 80psi over the course of a week. During a recent three-day ride my road tyres (25mm) got down to 90psi in the course of each day, having started at 120psi. And I mistakenly took them to 140psi before the start of day 1 without any noticeable difference in handling or harshness.
