valve problems

Pezski

This is a bit of a weird one. I'm riding a Kona Big Kahuna, with 29er wheels. Recently I've been having so many torn valves it is untrue - almost every time I go out.

The odd thing is that for the first year on this bike I had hardly a puncture, but since last summer it's become a serious problem. At first I thought it was a problem with a batch of tubes I'd bought (and went so far as to contact the manufacturer) but the problem isn't confined to them. The only thing I can think is that it's wear on the tyres which is making them looser, allowing slippage on the rim which pulls at the tube and causes the splits - at the base of the valve.

I'm actually having problems finding good quality replacement tyres - the only widely available 29er tyres seem to be for commuter bikes - which is a real shame as, in every other way, the bike is a joy to ride. In the log run, am I actually better off replacing the wheels with standard size, or will that screw up the geometry?

The Rookie

Presta or schrader, if they are prest are you using the lockrings?

(yes we had one recently, 5 torn tubes but never thought to use the lockring!)

26" wheels is just wrong, but it may not be the tubes fault, fit the tyre with a known part next to the valve, are the tyres slipping on the rim?

You can fit 26" tubes inside a 29er tyre if you want to try some different tubes, its a faff but it can be done.

Simon

Simon

bennett_346

Pezski wrote:

I'm actually having problems finding good quality replacement tyres - the only widely available 29er tyres seem to be for commuter bikes

hmm no, there are plenty of 29er tyres out there for mtb, you just have to look for them.

bennett_346

http://www.nextdaytyres.com/Tyres.aspx?Size=29+inch

386ka

Probably the tyres are slipping on the rim. At what pressure are you running them?

Pezski

Beginner - presta valves, always with the lock ring. I've considered forcing 26" tubes in to help against slippage.

ka, I don't think i'm doing anything differently than i was last year (I'm one of these fools that gauges pressure by thumb rather than an actual, y'know, gauge).

And bennett, ta for the link. Probably a case of slippage caused by wear and under pressured tyres.

thanks chaps

delcol

Pezski wrote:

Beginner - presta valves, always with the lock ring. I've considered forcing 26" tubes in to help against slippage.

ka, I don't think i'm doing anything differently than i was last year (I'm one of these fools that gauges pressure by thumb rather than an actual, y'know, gauge).

And bennett, ta for the link. Probably a case of slippage caused by wear and under pressured tyres.

thanks chaps

a tenner will get you a digital presure gauge,, then you will know exactly what psi is in your tyre,, and hopefully stop this happening again.