Why throw away usable tubes just to go to schrader valves? For a buck or two, you can buy a presta to schrader valve adapter that screws on the presta valve so you can pump it up at a gas station. You can pick up a pair of them at WalMart for two bucks. I switched from schrader to presta valves years ago when I first got a decent bike. It's all personal preference but I would never go back.