Have you ever heard an odd thudding noise come from your car and suspected the worst? Maybe your engine has an issue, maybe your muffler… Well, did you know that that thudding sound could also come from your tires? Read on to find out what could be making that thudding sound and what you can do to fix it.


You would be amazed at the things that can get into your tires, and rocks are a big one. Do you hear a thudding at a slow speed, and then once you get up to 25mph it stops? That is more than likely a rock in one of your tires. A rock has somehow wormed its way inside the tire and is now bouncing along in there. This can happen any number of ways.

Most people who have this problem though, have been driving through areas with a lot of gravel. Think old country roads, work sites, construction areas. The gravel is small enough that it is possible to wedge itself between the tire and the rim and work its way in, and smooth enough not to puncture the tire. Its also heavy enough to create that wonderful thudding noise that you know so well.

How it works

As your tire turns, the rock will slide along the bottom. As you start to build up a little speed, centripetal force will start to pull it along the side of the tire. Gravity however has different plans and so as the rock reaches the top of the inside of the tire, it will fall, creating that thudding sound. Once you speed up enough though, and the tires are rotating fast enough, centripetal force will overcome gravity and start to carry the rock around, allowing the thudding to stop, at least until you slow down, and then the entire process starts all over again.

What you can do

This problem is not that damaging to your tires, so in theory you could actually leave it alone for awhile. However, the thudding could start to make you crazy. Consider taking your car to a licenced mechanic. It shouldn't take very long to take off the rim, remove the rock, and replace the tire on the rim, and then put the tire back on your car.

There you have it, one of the possible reasons for why you might be hearing that horrible thudding noise. When all else fails, get it checked out by a tire specialist like PDR Automotive Inc.