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Old 05-27-10 | 03:42 PM
  #14  
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DiabloScott
It's MY mountain
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Joined: Sep 2006
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From: Mt.Diablo

Bikes: Klein, Merckx, Trek

Originally Posted by Jim246
Anybody ever experience a blowout or other problems from heating caused by braking? I am curious if I am worrying too much about it.
Happened to me ONCE. Learned my lesson... major blowout even left a welt on my calf. Singed my fingers when I touched it too.
All the advice about alternating braking etc here is good.

Thing is though, no one is really sure WHY the tire blows off when the rim gets that hot, only that it does (and some people even dispute that, contending that it only happens on a bad tire installation)
  1. Yes, pressure goes up with heat, but not enough for a blowout (blowout pressure on cold rims is *really* high. Also, rim temperature does not equal air temperature in the tube.
  2. Yes, rims expand when they get hot... expansion of the rim width could be a player.
  3. Maybe the rim softens up with heat enough to relax the shape just enough to let go of the bead?
  4. Does the bead itself expand - creating a larger effective diameter? (doubtful but who knows)
Lots of heated argument threads on this subject in the archives.

Last edited by DiabloScott; 05-27-10 at 03:46 PM.
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