Tyre slippage on rims

"Ben" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

During my Kona 100 ride at the weekend I really suffered from my tyres slipping round the rims on
steep descents and tearing the valves from the tubes.

Anyone know of a trick to prevent this? I lost about an hour on Sunday due to replacing 4 tubes
and it was only due to the generosity of others in giving me another couple of tubes that I was
able to finish.

The same thing happened to me on Sunday whist riding in the Peaks but that was because I punctured
on a downhill. All I can say is that I've never had nor heard of your problem before in all the
off-road miles I've done, what is your tyre/rim combo and what pressure do you use?

Pete

Peter B said:

"Ben" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

During my Kona 100 ride at the weekend I really suffered from my tyres slipping round the rims on
steep descents and tearing the valves from the tubes.

Anyone know of a trick to prevent this? I lost about an hour on Sunday due to replacing 4 tubes
and it was only due to the generosity of others in giving me another couple of tubes that I was
able to finish.

The same thing happened to me on Sunday whist riding in the Peaks but that was because I punctured
on a downhill. All I can say is that I've never had nor heard of your problem before in all the
off-road miles I've done, what is your tyre/rim combo and what pressure do you use?

I've heard of it before but never had it happen. I put it down to the very steep long descents on
Sunday that had continuous braking involved. The tyre wasn't moving much, maybe 1cm at the most but
it's enough to cause the valve to start to tear out of the tube.

The rims are Mavic 217 and the tyres are Hutchinson Python folding. Originally running at 40 PSI,
running at about 30 after I've fixed them the first time because that's the most I can get with my
mini-pump.

I never encountered the problem with the Ritchey WCS Z-Max tyres I was running so it could be that
tyre and rim combination are just a bit loose. I'm having some new wheels made with Mavic 618 rims
on. I tried the tyres on those and found them a tighter fit than the 217s so hopefully that will
cure it (bloody expensive solution!).
--
"We take these risks, not to escape from life, but to prevent life escaping from us." ***** replace
'spam' with 'ben' to reply *****

I've definitely had this problem too, although the severity depends a great deal on the tyre/rim/pressure combination.

Huchinson tyres on Sun rims (even at medium pressures) were truly dreadful in this respect, largely due to the beads being a particularly slack fit. But then I could change the tyres without levers (or unnecessary thumb strain).

My current Tioga Factory XC SL tyres on Mavic rims are much better, but were a complete [censored] to fit, so that may be unsurprising.