I have a few questions about wheel alignment. First, is it true that front-end parts must be free of wear before an alignment can be done? Some time back I had a car with about 75,000 miles, and I wanted an alignment at the time I had new tires put on. The guy checked out the car and said they couldn’t align it unless I spent several hundred dollars on ball joints and such. I blew them off and drove the car for some time afterward with no apparent side effects. If my tires are wearing well, can I assume my alignment is good?

I’ve heard that a lot of newer cars can’t be aligned. Why is this? What got all this started was a conversation with my neighbor about her unusual tire wear.

-Tommy Potrero, San Jose, Calif.



Wheel alignment is important for proper tire wear, and straight and stable tracking. Older, rear-wheel-drive vehicles required only a periodic front-wheel alignment (check and/or adjustment), while most newer vehicles have adjustable components in the rear as well. I’ll concentrate on the front alignment today.

The three front-wheel alignment angles are caster, camber and toe. Visualize a bicycle with two front wheels, parallel to each other, rather than one. Caster is the angle of the bicycle’s front fork, viewed from the side – relative to vertical. Most vehicles have a few degrees or more positive caster, similar to a bicycle. If one wheel has less caster than the other, a pull to that side is likely. Stability increases with a greater amount of caster, along with additional steering effort. Slightly increased tire wear also can occur with a large caster angle, as the tire leans during turns.

Camber is the inward or outward vertical lean of each wheel. Positive camber is out at the top, or bow-legged, and negative camber is inward at the top. Incorrect camber affects tire life because a leaning tire wears more on one side, and can contribute to a pull to one side.

Toe is a measurement of the wheels’ parallelism, as viewed from the top. Toe-in is pigeon-toed, closer at the front than back, and toe-out is the opposite. Incorrect toe will cause dramatically increased tire wear – usually wearing one side of the tires more than the other, with a feathered tread. If, when rubbing your hand across a tire’s tread, it feels smooth one way and rough the other, incorrect toe is likely.

Toe is adjustable on all vehicles, but with improved manufacturing accuracy, many no longer allow for caster or camber adjustment. Should a nasty pothole or curb disrupt the original alignment angle, after-market kits containing offset bushings or mounting plates often can be installed to allow adjustability.

It’s possible to align a vehicle with worn suspension components, but the angles go askew as road forces stretch the tolerances, rendering the alignment adjustments worthless. If a vehicle has tight suspension components, tracks straight and enjoys minimal tire wear, one’s alignment might be assumed to be OK, although suspension wear and alignment drift occur gradually, and might not be readily noticed.

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose.