The Physics of Wheelies: It’s About “Conservation of Angular Momentum”

Watching this video of Rockford, Illionois’ Byron Dragway’s annual wheelstand competition from last year got me thinking. Just why do cars and bike lift their front ends up off of the ground under sudden acceleration? I like science but I’ve never had much of an aptitude for physics. Fortunately, I know Dr. Robert Buxbaum, who has a PhD in chemical engineering, is a professor of nuclear chemistry, and runs Rebresearch, a company that makes hydrogen generators and purifiers. I asked Dr. B if he’d take a minute to explain the physics of wheelies. I wish my own physics instructors had explained things as clearly.

Conservation of angular momentum is what gets the thing up in the first place. If the rear wheels suddenly start to turn counter clockwise, the the body of the car starts to rise turning clockwise. If there is enough change in rotational momentum of the wheels, the whole car front lifts from the ground. It’s easier to “pop a wheelie”… if you want an impressively large, long duration wheelie, it helps to have big, heavy back wheels, a rear wheel drive car, and a relatively light front end.

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