"Doki" wrote in message
...
I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the
rim
under braking, and pulling the tube along with it, which eventually rips
the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't
want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any
odds.



The low pressure is your problem, allowing the tyre to rotate. the solution
is to increase the pressure!!

pk