Moving inner tube.

[Vetus Ossa]

As a follow up to my previous question “Front mech changing down problem,” I have another one.
I fitted a different tyre to the back wheel and took it around the block to see how it rode.
When I got back I noticed the valve stem at the pictured odd angle.
Have to say the tyre is loser on the rim than I am happy with.
When I rode the bike back from picking it up last Friday the rear wheel punctured and I had to push it the last mile home. When I took the tyre off I could see that the valve had been ripped out of the inner tube.
Is this wheel to be consigned to the scrap heap, or fingers crossed is there a fix.

[chris_suffolk]

What pressure are you running, are you nice and comfortably above the minimum ?

How hard is it to get the tyre onto the wheel? If it's a bit of an effort, then I would suggest it's the right size, if it just 'drops' on, then may be a little big.

[thirdcrank]

Rather than looking for a cause, I'd suggest trying for a solution first. Deflate the tyre completely and ensure that the valve is correctly positioned pointing exactly at the hub. Inflate the tyre hard, ensuring it's properly seated, tube not trapped etc. Ensure that the valve is still pointing at the hub. Go for a ride. If it still happens then there must be something really wrong and I can't imagine what it might be except a tyre that's not the right size for the rime

[Cugel]

It's a tyre that's loose on the wheel, so that the braking and other tugs of the road agin' the tyre cause it to revolve on the rims, tugging the inner tube with it. The only thing stopping the tyre revolving more is the valve of the inner tube. Eventually it cants over then rips, as your photo shows.

One reason that presta valves have a lock ring on the valve stem where it sits agin' the rim is to prevent this syndrome. Those Schraeder valves have no lockring and so get tugged sideways more easily.

You can change the tube to one with a presta valve and fit it through a small adapter that reduces the size of the hole in the rim to presta valve diameter. You then have a lockring keeping the valve upright, although the tyre is still trying to rotate 'round the rim, pulling at the inner tube, with the valve stem the only thing stopping it.

Alternatively you can try painting the tyre's edges (where they sit in the rims) with latex or some other sticky rubber goo, as this might (might) give enough extra grip of tyre to rim to prevent them rotating one against the other.

Cugel

[Vetus Ossa]

It's a tyre that's loose on the wheel, so that the braking and other tugs of the road agin' the tyre cause it to revolve on the rims, tugging the inner tube with it. The only thing stopping the tyre revolving more is the valve of the inner tube. Eventually it cants over then rips, as your photo shows.

One reason that presta valves have a lock ring on the valve stem where it sits agin' the rim is to prevent this syndrome. Those Schraeder valves have no lockring and so get tugged sideways more easily.

You can change the tube to one with a presta valve and fit it through a small adapter that reduces the size of the hole in the rim to presta valve diameter. You then have a lockring keeping the valve upright, although the tyre is still trying to rotate 'round the rim, pulling at the inner tube, with the valve stem the only thing stopping it.

Alternatively you can try painting the tyre's edges (where they sit in the rims) with latex or some other sticky rubber goo, as this might (might) give enough extra grip of tyre to rim to prevent them rotating one against the other.

Cugel

That does make sense to me. As it happens I do have a presta valve 26 x 1.75 inner tube so will give it a try.
Adaptors ordered from SJS so won’t be here anytime soon
Thank you.

[531colin]

If the tyre creeps round on the rim, it will rip a valve out...presta or Schrader.
Its a Schwalbe tyre, and there was a problem with some a year or three ago......basically, the wire bead is just wrapped round about 3 times. It SHOULD be embedded in rubber to keep it at the right diameter, but some missed their rubber embedding and these tyres can grow in diameter rapidly. I've seen one (on a wheelchair!) where the wheel could just pass through the tyre.
Check this tyre against the front tyre/wheel.....if this tyre is oversize, you have found the fault. The bead often "creaks" as well.

[slowster]

I had this happen with some Panaracer tyres on my MTB. Although they were fairly old, there was still reasonable tread on the tyre, but the tyre had aged/stretched to the point that I suddenly experienced several such punctures over a couple of weeks as a result of the inner tube movement damaging the rubber around the valve stem.

The cure was a new pair of tyres (Schwalbe funnily enough).

[Vetus Ossa]

I changed the tyres around this morning, front to back and back to front, pumped them up to 50psi and did the same ride around the block. The valves didn’t tilt back this time.
I can’t explain it but happy it seems to be okay now.
I will take it out for a longer ride tomorrow and see what happens.

[Brucey]

you don't say if the tyres are new or old, or if soap, talc etc was used as a lubricant when the tyres were fitted.

FWIW I agree with what Colin has posted upthread.

However I have also seen perfectly good tyres move on the rims if the interface between the tyre and the rim is contaminated with enough of any kind of lubricant. New tyres have 'mould release compound' on them and this (unless it is removed) can be enough to cause tyres to move around in first use. Fat low pressure tyres are most likely to move in this way, IME.

I would suggest that you wipe the tyre edge and the rim down with a suitable solvent (eg cigarette lighter fluid) and refit.

cheers