what does a track bar do
The purpose of a trackbar is to prevent movement of the axle/wheels from side to side. The adjustable trackbars will keep the axles centered (left to right) under the vehicle once lifted. Think of it as a right triangle. The axle is the base of the triangle, and the trackbar is the hypotenuse (diagonal line). If the vertical rise changes but the base does not, then the hypotenuse (the track bar in this case) would have to change or be adjusted to compenate for the new vertical height. If the trackbar is not adjustable then the axle will shift more to one side and no longer be centered under the vehicle.