I’ve torn two tubes at the valve this week. I just checked the current one and it looks like it’s being pulled round, i.e is at an angle but was put in straight. It’s pointing forwards when the valve is at the floor, so the tyre and tube must be moving under braking. Do I need to put something sticky on the bead to stop it moving?

(Rear wheel, 717, Pana XC. It was tubeless but had an accident & these tyres are impossible to inflate without a compressor so it’ll have to wait until I move back home)

Generally I find that happens either if I have too little air in the tyre or if I have too small a tube for the tyre size. More pressure or a larger volume tube perhaps. You probably won’t get away with the pressures you ran when tubeless.

I had this a while ago when i had electrical tape lining my rims,replaced
this with velox cotton rim tape and never had the same problem again.

Is the tube covered with talc? This will prevent the tube sticking to the tyre and might help.

Aha… I put lecky tape underneath the rim strips which are obviously not there anymore. you may have solved it gamo 😀

also thanks for the tip steveh

I had this problem with panaracer cinders on 717 rims. On upgrading to a 180 rotor up front the extra braking forces were enough to slip the bead around on the rim, ripping the valve out. This happened several times on one ride. Never had it with any other tyres since. All panaracer tyres seem to be a loose fit in my experience, so I’ve generally stopped using them.