Originally Posted by cyccommute

What are you using to pump up the tires? If the valve is failing when using a floor pump, you may need to deburr the rim. Use a counter sink tool to chamfer the hole. Here’s a good hand one that will do the trick.

If, on the other hand, it’s happening when you are using a frame pump, it may be the pump. A hand pump that you hold and pump perpendicularly to the wheel put a lot of stress on the valve. A pump with a hose like the Topeak Morph series will put less stress on the valve (and is easier to use).