Bump steer is when the chassis is in a compression or rebound cycle and each wheel experiences a different amount of toe change. Number one, both outer tie rods must be adjusted to the same length when the toe is set. Otherwise one tie rod is essentially shorter than the other which is what cause the car to got to one side and then the other when going over a hump in the road. Next, the idler arm and the pitman arm must follow the same arc. This is normally adjusted with the idler arm pivot mounting hole. Ever wonder why R&P steering doesn't have this problem ?
