Originally Posted by bikerlibre
Jason, I'll keep an eye from now on to make sure my stem is sitting squarely and make sure the nut is snug. It sounds like that may have been the issue. I'll also plan on putting in a new bladder after my next tire change - cheap insurance.
I've had an issue a few times in the past on my mnt. bike with valve stem flex but more so with the schraeder valves. The presta valves with their lock-nut helps prevent it. My tubes do only last a year though because I use slime tubes and get goat head punctures. I should probably go tubless.
Most of my issues have been with self sealing tubes .... Might be the sealant drying out the rubber? .... I hate it when my rubber dries out