Bump Steer

Bump steer is when the toe angle of the wheel changes as the suspension goes from full bump to full droop. Bump steer is generally undesirable because it causes the car to self steer as it goes over bumps and undulations on the race track.

Causes of Bump Steer

Bump steer occurs when the tie rod axis does not intersect the Instant Center throughout the full range of suspension movement.

Benefits of Bump Steer

Bump steer (also known as “roll steer”) can be used to change the toe angle of the wheels during pitch and roll. As the car rolls in a corner bump steer will cause the wheels to change toe angle and hence slip angle as the car goes through a corner. This can be used to increase the grip on the un-steered tires if they have not already exceeded their maximum available grip.