Originally Posted by iamdoingthat
1. Frame geometry/seating position. -- The geometry of the frame forces you to ride more bent over, reducing wind resistance?
That and it's a better position for generating power. I think this is the biggest advantage (speedwise) of a road bike compared to a hybrid or mountain bike.
2. Overall weight. -- Lighter frame, thinner rim/tire, lighter components?
Overall weight is going to matter that much, unless you're doing a lot of climbing up noticable grades. Thinner tires and lighter components probably help a little but not a huge difference.
3. Thinner rim/tire. -- Less rolling resistance lets you get more distance per pedal?
Probably a little, depending on how knobby the tires on the other bike are.
4. Or is that all a myth, and I'm just slow because I'm new to bike commuting and not in shape yet?
That's the big one.
Always look to yourself for more speed. A lot of the things you see racers do can be literally as minor as shaving several seconds off of an hour ride. You can spend a lot of money on very little gain and it can be frustrating. The biggest factor in speed is
you so that's always the first place to start.