Originally Posted by nelbur

My guess is that a spring rubber would lean the tire in more at the top, if as I suspect, your upper control arm is shorter than the lower arm. However, you can simulate the rubber by jacking the body up a couple of inches and checking the change in the "lean" of the wheel.

If the wheels appear to be standing straight up, your wear problem is more likely to be a toe in problem which wears the inside of the tires if they are toed out too much, and wear the outside if they are toed in too much.

PS On second thought, it depends on the orientation of the upper control arm as it now sets. If the ball joint end on the upper arm is higher than the inside end attachment points, a spring rubber would lean the tire out. And of course, if your car has struts on the front, than I have been of no help what so ever.