+1 for this type of adapter. You can leave them in place so if you ever find yourself needing air from a service station or other shrader type compressor or pump, you're all set. I like to unscrew them and close the presta valve before replacing them just for a little extra insurance against valve leaks. The adapters should cost between $0.99 and $2.00 at any bike shop. I have them on both of my bikes that have presta drilled rims. I actually like presta valves and these adapters give you the best of both worlds.