|Popping tubes left and right...||jcheyney|
Jul 28, 2002 5:58 PM
|My friend rides a Lemond Zurich with Bontrager Racelite rims. He switched to 700cX20 tires with high pressure tubes (135psi) because he had them on his old bike and thinks the smaller tires decreased his rolling resistance significantly.
We just did the RAGBRAI last week. He blew two tubes on the Century day. On the final day (while riding in the rain) he hit a hole in the road and blew a tube. We replaced it and his spare tube popped when he used his CO2 inflator. We replaced that one with my standard pressure (but correct size) tube and tried to inflate it with a hand pump. That one popped at an indicated 50psi on my pump. Since we were out of tubes and the rain was worsening we called our support truck and went home 50 miles from the end.
Does anyone have an idea why this would happen? We sort of gave up and have yet to take the tire and rim off but I am not sure why a spoke poking through or a defect in the tire would allow him to ride for days but pop intermittently. Is there something about these narrow, high-pressure tubes that cause them to pop on a regular basis? Is there some specific technique that has to be used to replace a tube to prevent this?
|Narrow tires need a little more love||spookyload|
Jul 28, 2002 8:00 PM
|The Racelite rims are very tall. I built a bike last year at Ironman Florida and the other mechanic couldn't even get an Axial Pro on the wheel without using a tire lever to install the tire. That is the major cause of tires flatting when installing a new tube. If you use a tire lever to install the new tube, it is very easy to pinch it and not even know it. If possible you should try not to use levers to reinstall the tire when replacing the tube. Other causes can be a twist in the tube while installing/inflating. This can be remedied by adding a little air to give the tube shape prior to installing to keep it from twisting. I would definately look at the rim tape. The higher pressure inside the wheel will force the tube into the rim holes at a greater PSI. Any deficiency in the rim tape could cause it to fail after any random point in time. I always use the velox and have never had any failures unlike the ritchey rim tape. Not the place to try and save weight. Check out the dead tubes and figure out where on the wheel the flat was happening. If you put your tire labels by the valve stem on the same side it will make this easier. This will tell you if it is a pinch flat, spoke hole, a twist(you will see a small rubbed line), or just the biking gods not smiling on you that day. I would say the pothole was a pinch flat like you get in Mtn Biking from running too low pressure. If so check the rim to make sure it wasn't damaged in the impact too. Man this answer seemed to run on way to long. Hope it helped.|
|re: Popping tubes left and right...||julio|
Jul 28, 2002 8:26 PM
|A friend of mine had a similar problem and the cause was defective tires, I think there was a problem with the bead, worth checking anyway...|
|re: Popping tubes left and right...||mja|
Jul 29, 2002 3:57 AM
|I have an 02 Lemond Zurich with Bontrager RaceLite rims. And I had tubes "popping" like crazy.
Here's what I found: Inside the rim was some very slight roughness -- some burrs, but quite seemingly inoffensive. However, after smoothing these out with sandpaper, no more problems with tubes losing air.
Check this out. Good luck!
|re: Popping tubes left and right...||jcheyney|
Jul 29, 2002 4:30 AM
|Thanks for the thoughts. We will look at the rims and tires and see what we can find. In our frustration we left the tubes behind so we can't analyze them. I had that thought but it was too late.|| |