Incidentally, twice the recommended psi is usually around the point the tyres themselves fail. A chap from Continental told me one of their standard test procedures is to inflate the tyres to the point at which they blow off the rims or tear themselves apart (I’m guessing there are a lot of ear-defenders in that test facility!) and then quote half that figure as the maximum recommended inflation pressure.
Of course, there’s a good chance that your rims will fail before your tyres do, if you’re attempting crazy high pressures on clincher rims, especially with big tyres. Tubulars are a little different – running pressures of up to 250psi is not uncommon!
Once I pumped my tires to 120psi while outside, the temperature was around 40F (under 5C) and when I put the bike inside my minivan after the ride one tube popped and the tire blew off of the rim on the way home because it was warm inside the car. I nearly drove off of the highway when that happened. The bike was few feet behind me. My ears were ringing for the rest of the day. Although the tire didn’t rupture, it was just blown off of the rim. I guess it wasn’t seated well. But man, was that loud!
The same thing happened to me, except that I wasn’t in the car. I used to keep my road bike tires (27″ x 1 1/4″) pumped up to 120 psi. Then one hot summer day I took it to work with me in the back of my station wagon so I could ride at lunchtime. When I went out to the car later the rear tire had blown off the rim and there were little bits of tube scattered around the cargo compartment. That night I put in a new tube and was pumping it up in my living room when it blew off again. My ears rang for hours. It occurred to me that it would be bad news if that happened to the front tire while I was riding, so ever since I’ve kept them at 95 psi (the recommended max). Of course, I have straight-wall rims. If they were hooked rims I’m sure I could get away with higher pressures.
When I was a young girl I once reinflated my tire at a service station using the “thumb” method of pressure testing. I guess I blew them too high as my rear blew out on me a half block later. I learned to be more careful as I walked home the 5 miles.
Thanks for being patient this morning while the commenting system was down. In my zeal to placate readers who wanted extra commenting features, I installed WordPress plugins that didn’t work as well as promised.
I’ll try to install equivalent code later on (for favorite-ing comments, etc.) but it might be a few days (I want to finish the mobile versions of the site first).
I noticed that the “Notify me of followup comments via e-mail” feature started working on Friday. Like on the old site, it only emails subsequent comments from that same day. Is there any chance of getting an option for it to be turned on once and then emailing all new comments from that point on, without having to turn it on every day? Or alternatively, could we get a “Delete” option? Then I could resume my former practice of posting an “empty” comment first thing every morning and immediately deleting it, just to turn on the email feature for that day.
Life is full of hard choices. Do I pump them up hard – less rolling resistance but a less comfortable ride – or leave them softer – vice versa. Should I fit wider tyres to make it easier on softer off-road surfaces – or skinnier for tarmac? Puncture resistance at the cost of weight and less free rolling? The ideal is to have different velocipedes for different circumstances – but my bank balance and storage space limits me to one tricycle…..
My road bike is carbon and my trekking/touring bike is steel so I always pump their tires hard (130psi and 100psi respectively). The frames provide enough comfort. On my aluminum commuter I run fat tires and a bit softer.
A timely comic! The 2.3″ tires on my mountain bike have a recommended pressure range of 35-65psi. For years I have been pumping them up to 40/45 f/r. Recently I punctured and pumped up the front by hand until it felt good enough. I rode some rough single track that just felt better, a little more comfortable, a little more grippy. When I got home I checked the pressure: 18psi. So then I lowered my rear tire down to 30. The bike was transformed. Less vibration, more traction likely due to the more maleable rear tire remaining in contact with the road. The front tire smears a bit on rocks and off cantor dirt, thus steers better.
This has extended to my road bikes too. 32-33mm tires pumped to 65/75 are more comfortable than 27-28mm tires at 85/95psi. On my local climb at nearly 4 miles and 1400ft vertical, my times on the big soft tires are equivalent to the smaller harder tires. And descents are fast and sure on a bigger contact patch.
Don’t even talk to me about 23mm tires pumped to over 100psi. Jan Heine has pretty much proven there is no measurable advantage to riding such non-tires and there are significant disadvantages.
Yeah, I have 2.2 tires on my MTB and I pump them to 30psi now. I used to pump them harder until someone pointed the obvious: grip. They have enough volume not to get pinched at that pressure and the suspension helps too. On a rigid bike that might be too low.
No, the account is still there. Now trying logging in first; I had been just entering my forum name & e-address, ‘cos I understood the new system only accepted posts from members. Let’s give this a whirl:
Bizarre. I checked on the gravatar site, which showed my image. I went to the profile page on this site and re-loaded the image – and voila! Here it is!
Riding MTB has definitely opened my eyes to running low pressure. I go with as low as I can without getting pinch-flats or the tire losing stability in turns. With 2.3′s I’m running 23 f / 27 rear.
That article about 15% tire drop also changed my view of road tire pressures. I ended up running slightly higher pressure than that article recommended, but much lower than I had been. While they “felt” slower at first, I think that is just because I was used to associating harsh=fast. But I realize that is not really the case. Back in my 23c days, I was able to drop from 120psi at both ends to 115 rear and 90 front with no measurable difference in time over distance. at ~200 lbs combined bike/rider weight I’m now running Jack Brown 33s at 55 psi front, 75 psi rear. I increase the rear for a load.
The idea that harder=faster has been pretty widely rejected in the MTB world. It is starting to be questioned by some road riders, but old ideas die hard. Obviously, you are going to want a higher psi on the road than on the trail, but as long as the surface has any irregularities, there will be a pressure at which higher psi serves no purpose, and may even be less efficient. I think that pressure is much lower than many people think.
As you say – we must remember that, as the linked article points out, smaller cross-section needs a higher pressure to sustain any given bump without bottoming out. Larger tyres have more air to cushion with so can absorb bumps with less deformation, as the load is spread of a larger arera/volume.
Under-inflated tyres (British spelling, BTW) plus heavy load (Yehuda’s survival kit) lead to pinch-flats. So I suspect that he’s being a bit hyperbolic.
Yehuda may have a lot of stuff in his ‘Bag of Holding’ as the space inside is infinite, but it weighs no more than the emty bag. So there is no ‘load’ other than the heavy old VS frame etc. So it possibly weighs more than most mountain bikes?
Sure, but… I ride mostly low pressures on all my bikes, never had a pinch-flat yet. According to my experience, with a larger-volume tire, the pressure low enought to allow a pinch flat is already also low enough to let you know about it – the wheel feels “floating”, not really stable in turns, etc. Though, of course, YMMV…
Incidentally, twice the recommended psi is usually around the point the tyres themselves fail. A chap from Continental told me one of their standard test procedures is to inflate the tyres to the point at which they blow off the rims or tear themselves apart (I’m guessing there are a lot of ear-defenders in that test facility!) and then quote half that figure as the maximum recommended inflation pressure.
Of course, there’s a good chance that your rims will fail before your tyres do, if you’re attempting crazy high pressures on clincher rims, especially with big tyres. Tubulars are a little different – running pressures of up to 250psi is not uncommon!
Once I pumped my tires to 120psi while outside, the temperature was around 40F (under 5C) and when I put the bike inside my minivan after the ride one tube popped and the tire blew off of the rim on the way home because it was warm inside the car. I nearly drove off of the highway when that happened. The bike was few feet behind me. My ears were ringing for the rest of the day. Although the tire didn’t rupture, it was just blown off of the rim. I guess it wasn’t seated well. But man, was that loud!
The same thing happened to me, except that I wasn’t in the car. I used to keep my road bike tires (27″ x 1 1/4″) pumped up to 120 psi. Then one hot summer day I took it to work with me in the back of my station wagon so I could ride at lunchtime. When I went out to the car later the rear tire had blown off the rim and there were little bits of tube scattered around the cargo compartment. That night I put in a new tube and was pumping it up in my living room when it blew off again. My ears rang for hours. It occurred to me that it would be bad news if that happened to the front tire while I was riding, so ever since I’ve kept them at 95 psi (the recommended max). Of course, I have straight-wall rims. If they were hooked rims I’m sure I could get away with higher pressures.
When I was a young girl I once reinflated my tire at a service station using the “thumb” method of pressure testing. I guess I blew them too high as my rear blew out on me a half block later. I learned to be more careful as I walked home the 5 miles.
Thanks for being patient this morning while the commenting system was down. In my zeal to placate readers who wanted extra commenting features, I installed WordPress plugins that didn’t work as well as promised.
I’ll try to install equivalent code later on (for favorite-ing comments, etc.) but it might be a few days (I want to finish the mobile versions of the site first).
I noticed that the “Notify me of followup comments via e-mail” feature started working on Friday. Like on the old site, it only emails subsequent comments from that same day. Is there any chance of getting an option for it to be turned on once and then emailing all new comments from that point on, without having to turn it on every day? Or alternatively, could we get a “Delete” option? Then I could resume my former practice of posting an “empty” comment first thing every morning and immediately deleting it, just to turn on the email feature for that day.
@Yehuda Moon: Good luck with the plugins. Freebie code often comes with freebie bugs.
This is another example of a strip born out a conversation I had with Rick.
Life is full of hard choices. Do I pump them up hard – less rolling resistance but a less comfortable ride – or leave them softer – vice versa. Should I fit wider tyres to make it easier on softer off-road surfaces – or skinnier for tarmac? Puncture resistance at the cost of weight and less free rolling? The ideal is to have different velocipedes for different circumstances – but my bank balance and storage space limits me to one tricycle…..
My road bike is carbon and my trekking/touring bike is steel so I always pump their tires hard (130psi and 100psi respectively). The frames provide enough comfort. On my aluminum commuter I run fat tires and a bit softer.
A timely comic! The 2.3″ tires on my mountain bike have a recommended pressure range of 35-65psi. For years I have been pumping them up to 40/45 f/r. Recently I punctured and pumped up the front by hand until it felt good enough. I rode some rough single track that just felt better, a little more comfortable, a little more grippy. When I got home I checked the pressure: 18psi. So then I lowered my rear tire down to 30. The bike was transformed. Less vibration, more traction likely due to the more maleable rear tire remaining in contact with the road. The front tire smears a bit on rocks and off cantor dirt, thus steers better.
This has extended to my road bikes too. 32-33mm tires pumped to 65/75 are more comfortable than 27-28mm tires at 85/95psi. On my local climb at nearly 4 miles and 1400ft vertical, my times on the big soft tires are equivalent to the smaller harder tires. And descents are fast and sure on a bigger contact patch.
Don’t even talk to me about 23mm tires pumped to over 100psi. Jan Heine has pretty much proven there is no measurable advantage to riding such non-tires and there are significant disadvantages.
BTW I weigh 175-180lbs.
Yeah, I have 2.2 tires on my MTB and I pump them to 30psi now. I used to pump them harder until someone pointed the obvious: grip. They have enough volume not to get pinched at that pressure and the suspension helps too. On a rigid bike that might be too low.
My last few posts have had no gravatar – Is it a problem with the system or with how I enter my details?
Did you actually add one to your profile?
Yep! – and it appeared beside the first post or few that I made after signing up for it – but checking back, even they have disappeared…..
It doesn’t appear your account exists anymore?
No, the account is still there. Now trying logging in first; I had been just entering my forum name & e-address, ‘cos I understood the new system only accepted posts from members. Let’s give this a whirl:
Nope! Still no gravatar!
Bizarre. I checked on the gravatar site, which showed my image. I went to the profile page on this site and re-loaded the image – and voila! Here it is!
HAPPY LABOR DAY!!!!!
Is it possible to remove ad banner from in front of strip?
What kind of device are you on – not able to reproduce the issue here at the Kickstand…
i experienced that too a few days ago, but it just went away.
low pressure on road bike tires has given me a significant lower runtime.
Riding MTB has definitely opened my eyes to running low pressure. I go with as low as I can without getting pinch-flats or the tire losing stability in turns. With 2.3′s I’m running 23 f / 27 rear.
That article about 15% tire drop also changed my view of road tire pressures. I ended up running slightly higher pressure than that article recommended, but much lower than I had been. While they “felt” slower at first, I think that is just because I was used to associating harsh=fast. But I realize that is not really the case. Back in my 23c days, I was able to drop from 120psi at both ends to 115 rear and 90 front with no measurable difference in time over distance. at ~200 lbs combined bike/rider weight I’m now running Jack Brown 33s at 55 psi front, 75 psi rear. I increase the rear for a load.
The idea that harder=faster has been pretty widely rejected in the MTB world. It is starting to be questioned by some road riders, but old ideas die hard. Obviously, you are going to want a higher psi on the road than on the trail, but as long as the surface has any irregularities, there will be a pressure at which higher psi serves no purpose, and may even be less efficient. I think that pressure is much lower than many people think.
Here is the article I was talking about: http://www.google.com/url?sa=t&rct=j&q=bicycle%20tire%2015%20drop&source=web&cd=1&cad=rja&ved=0CCAQFjAA&url=http%3A%2F%2Fwww.bikequarterly.com%2Fimages%2FTireDrop.pdf&ei=nuBEUNW_OOf96wGjzYGQBA&usg=AFQjCNGL_6p-7qkIU4Jd555EVfa1UXs5Lg
As you say – we must remember that, as the linked article points out, smaller cross-section needs a higher pressure to sustain any given bump without bottoming out. Larger tyres have more air to cushion with so can absorb bumps with less deformation, as the load is spread of a larger arera/volume.
Under-inflated tyres (British spelling, BTW) plus heavy load (Yehuda’s survival kit) lead to pinch-flats. So I suspect that he’s being a bit hyperbolic.
Yehuda may have a lot of stuff in his ‘Bag of Holding’ as the space inside is infinite, but it weighs no more than the emty bag. So there is no ‘load’ other than the heavy old VS frame etc. So it possibly weighs more than most mountain bikes?
Sure, but… I ride mostly low pressures on all my bikes, never had a pinch-flat yet. According to my experience, with a larger-volume tire, the pressure low enought to allow a pinch flat is already also low enough to let you know about it – the wheel feels “floating”, not really stable in turns, etc. Though, of course, YMMV…
OK I had a comment right after the comic went up that disappeared. What happened to it?
Nevermind, I found out what happened (I should have read more carefully)
Higher pressure (within reason) helps prevent punctures too.