Definition: Bumpsteer is a change in toe* angle caused by the suspension moving up or down. Bumpsteer is built into the geometry of the suspension and steering system, and has nothing to do with turning the steering wheel. The effect of bumpsteer is for the wheel to toe-in or toe-out when the suspension moves up or down. This toe change or “steering” occurs any time the suspension moves, whether it is from body roll, brake-dive, or hitting a bump in the road. Bumpsteer is undesirable because the suspension is steering the car instead of the driver.