Why Is A Proper Wheel Alignment Important?

by Don Elliott on February 7, 2012

Wheel alignment is a very important car component. Wheel alignment is the process of squaring up the angles of the wheels so they are perpendicular to the ground and tracking in a line parallel to one another.  Although the wheel alignment process would appear to be straightforward (pardon the pun!), it is not an easy repair. Only a trained auto repair technician using a properly calibrated alignment system can bring the measurement components together.

Older cars get out of alignment when suspension components and springs begin to sag. Any vehicle’s wheel alignment can become crooked from hitting potholes, misplaced curbs, and objects in the road. The tires are the first to show a problem. Uneven wear patterns almost always indicate that the tires are not running true to the road. An attempt at alignment will confirm an adjustment is required or indicate a worse problem. Bent suspension components, bad ball joints, or accident damage can be identified during the wheel alignment process.

There are four measurements that need to be within specifications for the vehicle to be properly aligned.

Camber Angle

Camber is the tilt of the wheel perpendicular to the ground. Positive camber indicates the top of the tire tilts to the outside of the car. For the camber to be negative, the top of the tire will tilt towards the center of the car. When the camber is set to vertical, the maximum amount of tire tread is on the road. The tire will wear unevenly if the camber is out of alignment.

Caster Angle

The front suspension system components include an upper and lower pivot point. These are commonly known as lower and upper ball joints or strut tower mounts depending on the type of suspension. Caster refers to the angle of deviance between the upper and lower pivot points when the car is steering straight ahead as viewed from the side of the car. Negative caster, or the pivot points tilted to the front of the car, makes the car harder to steer and impacts straight line tracking.

Toe Angle

Toe refers to the tire’s angle of deviation from the centerline as viewed from above the vehicle. If the car is running true, the tires tread is pointed directly to the front of the vehicle. Toe-in occurs when the tires are angled towards the center of the car and the steering wheel is set to go straight ahead. Toe-out occurs when the tires are angled to the outside of the vehicle track. An incorrect toe setting will cause feathered wear across the tire tread.

Thrust Angle

Thrust angle is measurement of the wheels from the centerline drawn perpendicular to the rear axle. All four wheels should be equidistance from the centerline. An incorrect thrust angle indicates the car is not tracking straight ahead the tires are not rolling in line with one another.

An accurate wheel alignment will add to your used car value. A wheel alignment reduces tire wear, improves handling, and helps the suspension perform better. In all, a proper wheel alignment equates to a safer vehicle. The car repair shop is given an “acceptable” range for adjustment of the suspension components when doing a wheel alignment. Request that the adjustments are made to the preferred settings rather than somewhere within the range. Most shops will be able to provide a printout to confirm that the adjustments were made to the preferred setting to maximize performance and used car value.



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