Originally Posted by
gaucho777
Is your valve cockeyed? If a presta tube in a schrader rim is free to rotate, it can lead to a bulge near the valve since the valve stem is more likely to move around in the bigger valve hole.
If the tire slides on the rim dragging the tube with it, trying to anchor it by the stem is a very marginal fix.
The amount of retention available before failure seems to be pretty much the same regardless if the valve is held perpendicular or slanted.
I'd be more inclined to believe that people with poor inflation technique when using hand pumps might benefit from more firmly seated valve stems.
Originally Posted by
gaucho777
A presta tube in a schrader rim can start to press out of the valve hole, causing the edge of the valve hole to cut into the tube. This will often lead to a flat over time, especially at higher pressures.
Any adapter used at the hubside face of the rim wouldn't do anything to protect against that.
What's "higher pressures" for you?
According to my pump, I run my commuter on 6 Bar, and never had that issue.
It's possible I suppose that my choice of rim tape and my habit of poking a rather narrow hole in it is what's been saving me from that kind of damage.
But that theory is getting shaky, since I've switched to using banding tape, which doesn't resist being pushed apart as well as fabric tapes, and I'm still not getting that kind of damage.
Besides, there's probably some spread in how the valve bases are reinforced and the size of the valve hole.