I stupidly took out the little plastic inset that goes into the wheel rim valve hole thinking it was a reducer to swap between using presta and Schrader tubes. I now can't find it and the problem is that without the plastic cylinder I am getting punctures where the inner tube joins the base of the valve (both on presta and Schrader) after about 20 mins of riding. It looks to me that the little plastic widget was also capping the inner part of the valve hole rim and that without it fitted the tubes are getting squashed directly againnst the metal and it is cutting into the rubber.
Annoyingly I cant find any of these plastic bits on a quick ebay search. Hopefully this will make sense to someone who might know where I can source one of these things. thanks
rubber grommet and talc on the tube ??
Yeah, put talc inside the tyre, that'll sort (it stops the tube sticking to the tyre)
I've lost loads of those inserts over the years, never replaced them, always did the talc thing though.
Is it similar to this?:
You aren't running panaracer tyres are you?
I had this once with a panaracer tyre. It took me many punctures and a 5 mile walk home but the cause turned out to be the tyre casing/bead had stretched so much that the tyre was rotating round the rim under load, ripping off the valve stem.
Changing to a different tyre solved the problem.
I'd be looking at the size of toothpaste screw tops / food packaging. You'll look odd measuring them in the aisle of the supermarket but the satisfaction of finding something exactly the right size, then having to wait until you've used all the contained foodstuff, will be worth it.
Lots presta valve nuts have a little step in them that's designed to go into a schrader sized hole and prevent the movement that causes flats
https://www.amazon.co.uk/Schrader-Valve-Presta-Valve-fits-Presta-Valve/dp/B001CJZ2M4
(just an example). Put those on with the stepped side to the rim and it engages really nicely
I just threw some of those adaptors out last week!
That SJS link is exactly what I had inside my various 521/721's over the years. Doesn't fit a schraeder valve though.
