Originally Posted by
JeffS
1) You're not necessarily any more aero on a road bike (especially if you're riding the hoods)
2) taller gears are rarely the limitation of the typical rider. So you don't max out your speed going down a hill... you rest and have more power for the climb up the other side.
My MTB position was very similar to my position IN THE DROPS on my road bike and my speed was very close - especially on a commute. Wider tires actually speed up the commute since I could ride over instead of around obstacles.
Assuming position can be whatever you want it to be on either bike, the only advantage I'll give the road bike is weight... and in certain situations gearing.
+1 to all that.
Weight is a grossly overestimated factor. 1) People make a big deal out of a pound or two on the bike while it's inconsequential in the total weight of the bike plus rider. 2) It's on the bike and rolling down the road - it's not like you're riding around holding that pound out in front of you nor are you lifting it vertically. You can push a lot more groceries around effortlessly in a cart than you can lift over your head at one go. 3) Weight slows down acceleration and climbing accentuates it, but once up to speed extra weight helps maintain that speed and helps overcome aero drag going downhill. It's a non-factor on a commute for the most part. A time-trial up l'Alpe d'Huez? Sure. "Jumping" to catch the wheel of a breaking-away rider? Sure. Your flat or rolling ride to work? Nope.