What is the gearing on the road bike vs. the hybrid? You might be able to get a different crank for the hybrid and get more speed out of it. My hybrid only has 38 teeth on the largest ring; I'm looking to change it out for one with 48 teeth. It turns out (for me, anyway) to be a lot cheaper than I would have guessed, even using Shimano components. If you have low, mountain-bike gearing on your hybrid, you may find you can get some life out of it by putting higher gearing on it, then you would have more choices for you commute and other riding.