No, I don't think so.
I'm a better driver AND a better bicyclist because I ride a motorcycle.
I'll grant that maybe, with me, it's because I never had a break after childhood riding. I transitioned seamlessly from tooling around the neighborhood and to school the way kids do, to commuting to work on my bici in heavy traffic at 16, to riding hundreds of miles a week both recreationally and commuting at 23, to racing at 27. So I never "learned" to ride a bike with new eyes. At 31 I burned out, mothballed the bici and learned to ride a moto.
Riding a motorcycle taught me a lot of the things others have mentioned - lane positioning, seeing with my whole eyes, avoiding target fixation, body steering (ok not relevant to cars
), eschewing distractions. When I came back to bicycling, I brought those skills back with me. I'm not sure I ever would've learned how to see at 70 mph by riding a bicycle at 20. I guess that's where MTBing might help (obstacles being closer means they appear to be coming at you that much quicker), but I never did much of that.
Last edited by OakLeaf; 03-31-2009 at 11:23 AM.
Speed comes from what you put behind you. - Judi Ketteler