Kind of a cool idea (even if they're not carbon). I take two bottles, one water, one gatorade. Takes me an hour in the Texas heat to finish them both. I refill them at the convenience store and drain them again before home. So what is that...88 oz. of water for a 30 mile ride...and I still lose a couple pounds of water weight in sweat. eeeeewwwwwwwwww.

Why not carry a second bottle? Weight weenie?