The tie rod end connects the steering rack to the wheel. It either has play or it does not; there is no acceptable in-between: a worn tie rod end makes the steering vague around the center position, and the car follows the grooves in the road.

Adjustable or uniball versions serve another purpose: correcting the alignment of a heavily lowered car, whose steering bar operates at an angle that causes the wheels to steer when going over bumps.