Contour Enthusiasts Group Archives Forums General Troubleshooting tire thumping

Did you lock them up recently? If so, you flat-spotted them. Nothing you can see but you sure can feel it. If you notice it more when the car is first driven then it's because the tires are cold and the flat-spot they got from being parked is taking a while to work itself out. If they're actually going thwack-thwack-thwack-thwack then it's a ply separation in the tire and you want to get it taken care of ASAP. Try jacking each corner up so the tire is just off the grouns and spinning the tire, while watching the gap between the tire and the ground. Any out-of-round issues will become immediately evident.