http://www.heidts.com/support_suspension_101.htmlhope this helps
EXPLAINING BUMPSTEER
Since the tie rod ends attach to the spindle steering arm, the tie rod controls the steering angle of the front wheels. If your car goes over a "bump" the spindle goes up and down in its swing radius, determined by the upper and lower arms . If the tie rod swings in a different radius than the spindle during this suspension travel; it will push or pull on the steering arm of the spindle, changing the direction of the front wheel, "steering" the car. And that is how the term and the monster "BUMP-STEER" were created, where 95% of the problems with incorrect suspension design are found. It is from people not really understanding this most important relationship between the tie rod length (not the overall rack length) and the spindle swing radius.They feel that if they are able somehow with enough modifications to the parts, to "physically assemble all the parts" that it must be OK. Then they pull down the driveway, over that first curb and low and behold: BUMPSTEER. When you drive a car with BUMPSTEER, the car tends to wander or hop around as you drive down the road over bumps and dips. You have to constantly steer the car to keep it in the lane. Not what you would call an enjoyable ride.
