Recently I manage to break BOTH valve stems while pumping up my tires. I was traveling, and only had my mini pump, not my regular pump. I got the tires pumped up, but the valve stems (right at the end--the part you screw back tight) simply broke off. Presta valves.

This means that I can no longer pump up my tires. I don't know yet if I can let air out and change out the tubes.

Has this happened to anyone else? I think it's a problem with my mini pump technique (I must be twisting it or something--it's hard to pump up to 100 psi with a mini pump).