There are all kinds of wear patterns that indicate different causes. You have to look at which side of the tread has accelerated wear, and whether it's smooth or choppy. Misadjusted "camber" will cause accelerated wear on the inner or outer edge of just that one tire. Camber is the inward or outward tilt of the wheel as viewed from in front of the vehicle. While camber only affects that tire, it can be off on both tires on that axle.
"Toe" is the direction the wheels are steering. Ideally the two wheels on an axle should be perfectly parallel to each other when driving straight. ""Toe-in" means both wheels are steering slightly toward the center of the vehicle. That causes the tread to walk closer toward each other until the sidewalls cannot flex any more, then they will snap back, and start all over. That causes a choppy pattern where one block of rubber will have a sharp raised side and the other side is worn down. You can feel that by sliding your fingertips over the tread. They will slide smoothly one way, but they will catch on the raised edges the other way. A suspension and alignment specialist will "read" the wear patterns, and he can determine if the wheels are toed-in or toed-out too much. Disregarding other factors that cause wear patterns, toe problems always affect both tires equally on the same axle, even when only one of them is misadjusted.
An ineffective shock absorber will allow that wheel and tire to bounce too much. Tires tend to bounce up at the same places, and bounce down at the same places. That causes dished-in pockets to form, mostly at the edge of the tread. The difference between this wear and toe wear is you will not typically feel the raised, sharp edges on the blocks of rubber like you do with toe wear. Also, if camber wear is caught early enough, that can even out if camber is readjusted or from rotating the tires. Choppy wear from a bad shock absorber will not even out if the shock is replaced or if that tire is rotated to a different corner. Once the dished-wear occurs, it will only accelerate.
If you are not sure what is causing tire wear patterns, have the vehicle inspected at a tire and alignment shop. Sagged springs will cause rapid tread wear because the suspension geometry will be wrong. That allows the wheels and tires to slide left and right across the road surface too much as the vehicle bounces up and down. This is an especially bad problem on lifted trucks and lowered cars. There will not be any unusual wear patterns, but the tread will wear down to nothing much too quickly. All alignment specialists have small books that show where to take the ride-height measurements on every model and year, and what they are supposed to be.
Thursday, December 28th, 2017 AT 12:45 PM