bikes capitalize on using little power ("little" being a relative term here) and being very light. On cars, there's so much more power and torque to spare, that those few pounds extra on the wheels aren't going to make that big of a difference. Notice that someone ran the 1/4 mile 0.3 seconds faster with lighter wheels (3rd reply to this post), now would you 'feel' 0.3 seconds on the street day to day?
