How do you know if your car needs a front end alignment? Vibrations, shimmy, and shaking felt in the steering wheel are usually not a sign of needing a front end alignment. A front end alignment, or four wheel alignment as it is commonly referred to these days due to the fact that the rear end of the vehicle can also be adjusted, does just what the name implies align, or line up the direction of the wheels so the vehicle is pointed in a straight line.

Caster, camber, and toe are terms used to describe the direction of the wheel in relation to the body of the vehicle. The front of the tire can be pointed in toward the center of the vehicle thus "toed in." When the front of the tire is pointed outward, it is referred to as "toed out." Both of these problems can quickly wear down the tread of a tire and can cause a "pull" in one direction of the front end. The top of the wheel can also lean in toward the center of the vehicle or lean out away from the vehicle, causing a camber problem. This situation can also cause tire wear and a pull to one direction in the front end. Caster measures the relationship of the left and right wheels to each other. If one wheel is farther forward or back from the other wheel, then there is a caster problem. Caster will usually not cause tire wear, but will cause a pull in one direction, and this problem is commonly found on wrecked vehicles.

So what causes shimmy and shakes in the front end? The biggest culprit is an out-of-balance or out-of-round tire. As the tread on the tire wears, it will need to be re-balanced to evenly distribute the weight of the tire and the wheel. To do this, small lead weight is attached to the outside of the wheel and a machine is used to spin the tire and wheel to check balance. Tires should be balanced and rotated every 12,000 miles (approximately every four oil changes) to ensure even tire wear and extend tread life. Out-of-round means the tire has worn unevenly and cannot be balanced. An out-of-round tire will have to be replaced. I have even seen new tires that were out-of-round due to a manufacturing defect.