Steering problems

My car has recently begun to develope a front end shake or shimmy. It also makes a slight thumping noise, like a flat tire, but not nearly so loud.

Any idea of the problem?

More info would be helpful. Make, model, year of car. Miles and age of the tires? Is the shimmy the same at all speeds or is does it occur in a certain range?

A couple of examples from personal experience, a 98 Windstar that would shimmy at low speeds with the steering wheel moving from side to side. That turned out be a a slipped belt in a front tire which had to be replaced. The thumping noise suggests this also.

An 86 Camaro that started to shake badly at 60 - 65 mph. The tires needed balancing. An 88 Chevy Beretta that developed a shimmy between 40 and 55 mph. The tire had sufficient tread but were a few years old, new tires fixed the problem.

Finally, an 86 Colt with 2 new tires that shook violently over 40 mph. Although the new tires were the same size (155/80R13) as the originals. Upon visual inspection the new tires were obviously larger in diameter than the original. Four matching tires, later the car was fine. Since then I buy 4 tires at a time.

Ed B.

The car is a 95 ford with about 100k. The tires are probably 5 years old, but the car had light use, so the tread wear is good. Maybe 20k and they are 80 k tires.
If I rotate the front tires to the back I should then be able to immediately tell if this is the problem, correct?

You were right on the money.
Thanks.