Alignment

When and why should I have an alignment done?   Once a year you should have the alignment checked. Look at the tires that have been on the front of the car. Are they wearing evenly across the tread? Is the wear pattern the same on both front tires? On some vehicles especially vans, the outer edge of the front tire may wear more than the rest of the tread. This is because of the manufacturer's suggested caster setting causes the tire to lay over on it's edge when you make a turn. Here are some other signs of trouble:

Middle of the tire wearing - caused by overinflation
Both the outside edge & inside edge wearing more than the middle - caused by under inflation
One tire wearing very differently than the other - alignment needed


Eddie Richardson repairs a tie rod end for a customer's car to enable
him to perform a quality alignment on the vehicle.

Cupping or scalloping of the tread, rough uneven wear, tread looks like it is corrugated, tire is very lumpy and bumpy - generally caused by the tire itself. Look to see if the words "All Season" are on the sidewall of the tire. If the tire is an all season and you have a front wheel drive car and the rear tires look like someone took a hot knife and scooped out small pieces of rubber and the shocks are not leaking oil and there is no other symptoms of bad shocks, then the tire is probably at fault. This symptom is one that sells more shocks when, in my opinion, 90% of all cupping or scalloping is caused by the tire itself.


Pictured here is the John Bean Computer Alignment Machine which
is State-Of-The-Art Technology.

Car pulls to one side or the other - Proper procedure is to first check the tire inflation. If that doesn't correct it then the two front tires should be swapped side to side. Then one of three things will occur:

If car continues to pull to the same side it will need an alignment.
If the car quits pulling and there is no unusual tire wear then all is OK. Spending more money at this point is useless.

If the car pulls to the other side, it has to be a tire related pull created by a defective tire.

Expect to pay around $35 to $100 for an alignment, depending on whether the rear wheels are used as references to set the car up (called a thrustline alignment) or a full 4 wheel alignment where all four wheels are checked and adjusted. This is one job on your car that will always have symptoms. So, if there is no pulling problem, no abnormal tire wear, then there is no need for an alignment.

Alignment

Tires should be checked monthly for signs of irregular wear in both tread and shoulder areas. Irregular wear indicates the need for a wheel alignment or suspension repairs. Also, when a replacement set of tires is fitted to a car, a wheel alignment is mandatory. Cars with four wheel independent suspension systems or cars with four wheel steering require four wheel alignment.

The three elements involved in wheel alignment are angles referred to as caster, camber and toe. Each affects the vehicle's performance.

Caster is the angle between a vertical line and a line drawn through the center of the ball joints (steering axis) when the vehicle is viewed from the side.

Caster is called positive when the steering axis tilts toward the rear of the vehicle at the upper steering pivot. Positive caster helps in maintaining directional control of a vehicle, tends to return the vehicle to a straight ahead position when cornering, and helps compensate for the crown on a road. Most cars are engineered with positive caster.

Positive Caster
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Negative Caster
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Improper caster can cause hard steering, increased road shock, reduced straight line stability and cause the vehicle pull to one side or the other.

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Email Murrell Brothers Tires

 

Camber is the angle between a perpendicular line and a line drawn through the centerline of the tire when the vehicle is viewed from the front.

Negative and Positive Camber
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Camber is called positive when the tops of the tires tilt away from each other. Camber helps distribute the vehicle's weight across the tire contact patch during cornering for reduced tread wear and is used to fine tune a vehicle's handling characteristics.

Incorrect camber causes uneven tire wear, poor steering and vehicle stability, and vehicle pull.

Toe refers to the angle between a line through the center of a vehicle and lines drawn through the centerlines of the tires when the vehicle is viewed from above.

Toe-In and Toe-Out

When the tires are closer together at the front than at the rear, the condition is called toe-in. When the tires are closer together at the rear than at the front, the condition is toe-out.

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The toe adjustment is the most critical to tire wear. Incorrect toe results in rapid and uneven wear.

When a manufacturer designs a car, engineers select these elements (angles) and establish them as specifications for the best overall vehicle handling performance. Failure to properly align a car's wheels can result in excessive tire wear, excessive fuel consumption and unsafe handling.