Doug McAllister/Under the Hood: Tires

Q. Maybe you can share your thoughts on this problem. I have a 2004 Lincoln LS with 65,000 miles. When I had 15,000 on it, I started hearing a thumping. The dealer at the time said it may go away (cupping) with proper tire rotation. I already had the tires rotated at least twice at that point in time.

At 30,000 miles I decided to get rid of the Continentals that came with the car and I purchased a set of Yokohamas. Those lasted maybe 3,000 miles and the “thumping” returned. I have since taken it to two different tire stores, and a different dealer seeking a remedy or possibly some good advice on what is causing this problem.

I have had alignments done twice and rotate the tires every other oil change. I never have come across a problem of this nature before. One set of tires maybe, but two? I am told by all these gentlemen that to fix this I should buy another set of tires!

I can’t see putting out another $600 for a third set of tires not knowing this isn’t going to happen again. Is it possible I could have a bent rim?

A. This is a tough one to speculate on without driving the car and being able to inspect the wheels and tires. Here are the things I would look at if you brought the car in to me:

First a test drive to get a feel for the thumping; I would be looking for any changes with speed, braking and cornering.

I would perform a thorough inspection of the wheels and tires. I would look for any cupping or flat spotting on the tires — which would be unusual with only a few thousand miles on the tires.

If I was fairly convinced it was a tire issue, I would try to isolate which one by moving the tires around the car to see if the thumbing moved or changed in any way. I would also check the balance of each tire.

I would also perform a thorough inspection of the steering linkage and suspension. These parts would include tie rod ends, ball joints, struts and strut mounts, sway bar bushings and sway bar links. Some of these components could also cause a thumping sound or sensation. A worn-out suspension component could cause the tires to get a choppy pattern worn into them prematurely.

You did not say, but is there anything custom on this car, such as custom wheels or anything like that?

The answer could be another set of tires, but if it is, there has to be something causing them to wear poorly. You could also find somebody with a Road Force Balancer and give that a try before splurging on another set of tires.

I hope this was of some help.

Ÿ Douglas Automotive is at 312 S. Hager Ave., Barrington, (847) 381-0454, and 7218B Virginia Road, Crystal Lake, (815) 356-0440. For information, visit douglasautomotive.com. Send questions to underthehood@dailyherald.com.