Stop valve stem ripping out

Ripping your valve stem out is a terrible way to end your ride. Try this next tire change: when tightening the rim lock, (especially on a fresh new tire) make sure to re-tighten it after a bit of riding. The rim lock will "bite" into the tire slightly after a few stops and starts. Tightening about 80-90% followed by re-tightening will increase the "bite", more than one extreme torque job. Rims can be deformed quite badly from over tightening rim locks.

If very low psi/run-flat ability is desired, using two rim locks spaced 180 degrees (opposite each other) on the rim is the best option.