What do I need to fix if I'm having problems with my rear tires being worn down on the inner side of the tires? I have already replaced the rear struts.
have the same problem?
Sunday, May 24th, 2015 AT 6:46 PM
Not necessarily any parts. Tire wear is an alignment issue. When parts are replaced, especially struts, the car has to be aligned. In this case the struts are not involved in the rear alignment, but on the front, the lower mounting hole is oval-shaped on replacement struts or it can be ground into an oval on the original struts. That allows the lower bolt to move so the spindle can be tipped in and out. That tips the top of the wheel in or out on top. That adjustment is called "camber". It is the first one that's set during the alignment.
There's actually two alignment angles that will cause excessive wear on the inner edges of the tires. The first is excessive negative camber, meaning the wheel is tipped in on top. It is important to note that misadjusted camber always only affects that tire and none of the others. Each tire's wear pattern is affected only by its adjustment.
The second angle is different. That is "total toe". Toe is the direction the wheels are steering. It is common on front-wheel-drive cars to find one or both wheels turned slightly to one side or the other. What's important is the reading of both wheels together. As long as both are turned an equal amount, they will still be parallel to each other. THAT is what's needed for good tire wear. In your case what could be happening is one or both wheels are steering away from the center of the car. That's called "toe-out". Regardless which wheel(s) is set wrong, the excessive wear will be on the inner edges of both tires.
Because it is so common for the rear wheels to be turned to one side a little, all alignment computers today look at the rear ones to calculate where to adjust the front ones to end up with a perfectly straight steering wheel. Also, a lot of cars including the older versions of your model were adjusted at the rear by installing shims. You have to pick the shims that give the best or closest adjustment but they're rarely perfect. That also makes it necessary to adjust the same "error" into the front wheels so they will be perfectly parallel to the rear wheels, and therefore, you get that nice straight steering wheel.
Your alignment specialist will inspect the steering and suspension components before doing the alignment, and he will measure ride height. Even if he sets all the adjustments to the exact specifications, you'll still have bad tire wear if the ride height is wrong. This is a real big problem for people who lower their cars or raise their trucks. The control arms go through specifically-designed in arcs as the body moves up and down as it goes down the road. Altering ride height changes those arcs, meaning it changes the motions the wheels go through and the movements that take place. The numbers on the alignment computer screen, in that case, only pertain to the car when it's standing still on the hoist. Those number will not translate into good tire wear on the road.