Xue Sheng
All weight is underside
In Colorado, a bicycle is specifically defined as a vehicle so DUI laws apply. There is also a specific law against riding an animal while intoxicated, so although it's not actually a DUI, you can effectively get a DUI while riding a horse.
The same should apply to fists. They're not deadly weapons in the legal sense, and there are abundant laws already addressing the issue of striking with various body parts.
In NYS a bike is a vehicle until the rider's feet touch the ground...then the rider magically becomes a pedestrian and the bike is no longer a vehicle.