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Why would you get many punctures , right where the valve is, on a skiinny tyred bike?
On both wheels. The tyres are 700 20-28C,almost/new, Cant feel anything inside the tyre.
The tubes are Specialized presta 700 20-28c, with long valves, these are deep rim wheels.
Blowing the tube up, there is a slow puncture, by the valve, just off centre
Whereas the rest of the tube inflates to 2+ inches diameter, this tube section is only half an inch or so diameter
Anyone else had this problem, or know what to do?
Latex tubes were suggested, but Im guessing its a case of buying better brand of tubes
I'm guessing tyre is old, loose on rim and moving under braking. That pulls the inner tube with it but it's fixed at the valve so that's where the major stretch occurs
New tyre is the answer but talc on the tube is a decent shout as a temp fix (doesn't stop the tyre moving but lets the tube stay put)
The weird inflation is prob just due to differing thickness of the tube (often reinforced a bit near valve, but not always IME)
Some tubes are constructed with a reinforced section around the valve. I'd investigate the rim closely around the valve hole to see if there is a burr - even time the wheel revolves the changes in pressure means the inner moves around the tyre and the burr / sharp edge will cause a puncture. Talc helps reduce friction / improves rolling resistance.
there is a burr right by the valve (on one wheel), I'll get it smoothed out
Is there a brand of tube that would be a better bet in this case?
Would SLIME filled tubes work?
If it's all due to a burr, and you remove it, you prob don't need to do anything about other tubes
Slime tubes do work for small holes IME but not if you run high pressures - and I'm not sure any sort of jizz is great for holes on the rim "side" of the tube, as gravity would pull it away from the hole
there is a burr right by the valve (on one wheel), I’ll get it smoothed out
Erm... 😀
What brand of tube are you using? I just use standard continental tubes these days. Not the lightest or cheapest but after a speight of puncture issues.. I don't have issues any more.
Specialized tubes should be ok quality wise.
If you have wide rims and a baggy bead then tyre slip under acceleration and braking can slice valves.
Ask me how I know this? 😡
The rims are 15mm (between edges), so are these the correct size tyres and tubes?
The tube with a puncture( at the moment) is a specialized THIN
The other is a specialized regular
There is a tiny scratch on the inside of both rims ,which would be covered by the tyre.