Help! My car shakes!
When I first started in the tire business many years ago, one of the first things my dad taught me was how to diagnose a vibration. Vibrations, he told me, follow the path of least of resistance. For instance when you feel a vibration in the steering wheel, it is most probably in the front suspension. When you feel it being transmitted through the car seat, it is probably in the rear tires. Of course that was in the days of solid rear axles, but you get the idea. One misconception I’ve heard for years is that a wheel alignment will correct a vibration. An alignment resets the suspension geometry to very specific measurements, it does not in itself address vibration issues unless there is a loose part in the suspension.
Wheel balance is the most common cause of vibrations. When a vibration comes in or out at a specific speed it is almost certainly a wheel balance issue. For instance if your car vibrates between 45 and 60 miles an hour and at no other speeds, you probably need to have your tires balanced. Even more specifically, if the steering wheel shakes between those speeds, you probably need your front tires balanced.
When a vibration comes in early and get progressively worse, it has to do with the physical shape of the tire. When a tire ’separates’ often the tire is mis-shapen and no longer round. This issue only amplifies as you go faster. Modern quality and material control procedures have made this exceedingly rare unless the tire has had extreme impact damage.
The last type of vibration I want to mention is braking. When your steering wheel shakes during braking you probably have warped brake rotors. The brake pads are no longer able to press flat against the brake rotors during braking and this causes vibration as well.
Vibrations and shakes can be annoying, but a basic understanding of how your car works can help you get to the root of the problem.
|Help! My car shakes! was written by Brian Doucette of TireTeam|