Wheel alignment and Wheel Balancing are two completely different things, but most people continue get them confused. Essentially a wheel alignment consists of adjusting the angles of the wheels so that they are perpendicular to the ground and parallel to each other. The purpose of these adjustments is maximum tire life and a vehicle that tracks straight and true when driving along a straight and level road. Wheel Balancing, on the other hand allows the tires and wheels to spin without causing any vibrations. This is accomplished by checking for any heavy spots on the wheel-tire combination and compensating for it by placing a measured lead weight on the opposite site of the wheel from where the heavy spot is.
The symptoms of a car that is out of alignment are:
- Uneven or rapid tire wear
- Pulling or drifting away from a straight line
- Wandering on a straight level road
- Spokes of the steering wheel off to one side while driving on a straight and level road.
The symptoms of a wheel that is out of balance are:
- Vibration in the steering wheel at certain highway speeds.
- Vibration in the seat or floorboard at certain highway speeds.
- Scalloped or cupped wear pattern on the tires
Wheel Alignment: To find out if you need an alignment, first check each tire and look for uneven wear patterns. The problem with this method, however, is that if you can see a wear pattern like the ones listed below, it may be too late to save that tire. This is why it is a good idea to have your alignment checked periodically.
At each tire, take a coin and insert it in the tread at the inside, center and outside.
Over inflated Tire: If the tread is deeper on the edges than in the center, the tire is over inflated.
Under inflated Tire: If the tread is deeper in the center than the edges, the tire is under inflated.
Tire Wear from Wheel Alignment Problem: If the tread is deeper on one side than the other, have your wheel alignment checked soon.
Tire Wear from Wheel Alignment Problem: Run your hand back and forth across the tread, being careful not to cut yourself on any debris or exposed steel belt wire. If the tread is smooth in one direction, but jagged in the other you have what is called a "saw-tooth" wear pattern which is caused by a toe-in problem. Have the alignment checked as soon as possible as this condition causes rapid tire wear.
The first two conditions do not call for a wheel alignment but the second two do. If these wear patterns are pronounced, you should replace the tires or move them to the rear before aligning the car. Ask your alignment specialist to be sure.
Another indication of an out-of-alignment condition is a car that continuously drifts or pulls to one side of the road when you let go of the wheel. A car that is hard to keep in a straight line without constant steering corrections is also a candidate. These conditions may or may not also contribute to premature tire wear.
A wheel alignment cannot be done on a car with loose or worn front end parts. The technician will first check for worn parts and inform you of any problems before beginning the alignment.
The best type of wheel alignment is a four wheel alignment. Many cars today have adjustable rear alignment settings, but even for cars without adjustments in the rear, a four wheel alignment will allow the technician to identify any rear tracking problems and compensate for them with adjustments to the front.
After the wheel alignment is finished, you should drive the car on a straight and level road and check that the car goes straight and that the steering wheel is in the proper position with the spokes level. If you notice a problem,take the car back and have the technician drive it and fine-tune the alignment settings.
Wheel Balance: Out-of-balance tires will cause a car to vibrate at certain speeds, usually between 80 and 100 kph. A tire is out of balance when one section of the tire is heavier than the others. One ounce of imbalance on a front tire is enough to cause a noticeable vibration in the steering wheel at about 100kph. To balance a wheel, the technician will mount it on a balancing machine which spins the wheel to locate the heavier part. He will then compensate for the heavy part by attaching a lead weight on the opposite side. Many people are pleasantly surprised at how smooth their car drives after balancing all four wheels.
Most high quality tires will hold their balance fairly well and go out of balance very gradually. If you notice a vibration that wasn't there the day before, it is possible that one of the lead balancing weights fell off. If you feel the vibration mostly in the steering wheel, the problem is most likely in a front wheel. If the vibration is mostly in the seat, the problem is probably in the rear.