Bump steer is the change in a car’s toe angle as the suspension compresses. As you push your car down, you'll notice that the toe-in changes - this effect is called bump steer, and the amount of bump steer your car has can be adjusted by changing the vertical angle of the steering links (when viewed from front or back), by raiser or lowering the links either at the inside (rack) or at the outside (steering arm.)
Bump steer is usually adjusted by adding or removing shims at the inner or outer studs of the steering link.
To get the least bump steer, that is, to keep the toe angle consistent throughout the suspension travel, you want the steering links to be parallel with the lower suspension arm.
Steering links down at outer end / more toe-in bump steer
- Increases toe-in (decreases toe-out) when suspension is compressed. See our toe article for the impacts of the toe angle
- More in-corner steering
- Suitable for smooth tracks
Steering links up at outer end / more toe-out bump steer
- Decreases toe-in (increases toe-out) when suspension is compressed
- Less in-corner steering
- Suitable for bumpy tracks
Active toe is similar to bump steer, but in the rear of the car.