Why does my car shimmy when I drive it?

Lloyd's Question: "What can cause a shimmy while driving at highway speeds?"

There are several possible causes, but the most common is tire balance. If you have a shimmy that you can feel in the steering wheel when driving at higher speeds it usually indicates a front tire out of balance. If you feel it more in the seat, then it could be a rear tire. Either way you'll want to have all four tire/wheel assemblies rebalanced. If it's a simple balance where only weights are needed, then any tire balancer will do the job, but for more complex issues where tire to wheel mounting position is an issue, generally only a "Road Force Variation" type balance will cure this. If you have a persistent shimmy or vibration issue, you may want to seek out a shop with a "Road Force Variation" type balancer. If the shimmy is only felt when braking, you may have warped brake rotors. This is fairly common with modern high efficiency disc brakes. The rotors will need to be resurfaced to eliminate this kind of shimmy or vibration.