Wheel alignment on a car is important for the life expectancy of the tires. Poor alignment is one of the leading causes of uneven and premature wear of tires. Although other factors such as the lack of tire rotations and tire balancing can lead to premature wear of tires, most often adjustments can be made to the alignment of a car to assist in the longevity of the tires. Normal driving conditions, after time, can easily cause the necessity of wheel alignments. Abnormal driving conditions, such as driving on dirt or potholed roads, can intensify the problem and necessitate the need for frequent alignment checks and adjustments.
The function of wheel alignment is to keep the thrust angle of the vehicle straight. This includes the steering wheel. There are three basic angles of the tire to consider. Toe adjustment is the most common because it creates the wear of a tire more rapidly. The toe is the parallelism of the tire between the wheels; in other words, how the tire points directly forward in conjunction to the angle of the vehicle. Toe-in would point the tire inward and create uneven wear on one edge of the tire. Toe-out would point outward, which would create edge wear of the tire. Camber is the angle of the tire as it is positioned to the knuckle or the strut of the suspension. A positive camber would angle the top of the tire outward and the bottom of the tire inward. Negative camber would position the angle of the top of the tire inward and the bottom outward. Zero camber would place the tire as it should, straight up and down. The last adjustment of an alignment function is the caster of the tire. Because caster deals only with steering stability, the effort of steering and the return of steering and does not compromise the wear of the tire, it is often overlooked. Viewing the tire from the side, caster is the forward or rearward tilt of the tire and applies only to the front tires in most cars.
To identify whether your car needs an alignment, there are a few easy tests. Making sure all of your tires have the proper air pressure is the easiest. Inspecting the tread wear of each tire is also important. Once driving the vehicle, check to see whether the steering wheel is centred. An off-centre steering wheel is a good indication that the toe is out. A vehicle that pulls to one side when you let go of the steering wheel or always has to be corrected is another telltale sign of the need for an alignment. Air pressure between two tires on the same axle can create a wander or pull, so it's important to check tire pressure before determining whether your car needs an alignment. Something else to consider is road crown. Most roads are designed to be higher in the middle and angled downward to the right. This is so rain and melting snow will follow the angle of the road and not create large puddles that can cause hydroplaning. Because of this, most vehicles always have the effect of a right wander. To check this, drive on a two-lane highway in the left lane--your car should create a slight wander to the left. Uneven tire wear and vibration when driving are also symptoms of a necessary alignment. Depending on the severity of the tire wear, new tires might be recommended before pursuing an alignment.
Where you live and the kind of roads you drive on greatly affect the alignment of your vehicle. More bumps and wear and tear on the suspension of your vehicle can increase the odds of needing an alignment more often than driving on smooth, paved roads. However, after a certain amount of time, because of the stress on the suspension and steering components of a vehicle, an alignment will be needed even under ideal driving conditions.
There are two-wheel and four-wheel alignments that can be made on vehicles. Many cars allow four-wheel alignment. However some older cars might need full contact shims applied to the rear axles to make adjustments for rear camber and toe if there are no alignment options and either the rear camber or toe are out. Front-wheel alignments are the most common because the tie-rod ends and angle of the caster are performed to prevent pulling or tire wear. In newer vehicles with rear adjustments available, toe and camber are also checked and adjusted if needed. If only a front-wheel alignment is performed, it is called a two-wheel alignment. If a front- and rear-wheel alignment is performed, it is called a four-wheel alignment.
Tire wear is not the only symptom to determine whether you need an alignment. Worn or malfunctioning front-end components might also be a cause. Ball joints, tie-rod ends (inner or outer), idler arms and bad struts or shocks also contribute to premature tire wear. Not rotating tires per maintenance schedules is another common cause for premature tire wear because the front tires will wear out more quickly because of the stress of steering. Improper tire inflation is yet another leading cause of premature wear. An overinflated tire will wear across the centre of the tread, and an underinflated tire will wear on both outer edges. The condition of the tires and front end should always be checked and replaced if necessary before performing an alignment.
Have the alignment checked on your vehicle at least once a year, more often if you drive on bad roads or have high annual mileage. Follow the recommended maintenance schedules for tire rotations and balances. Check your tire pressure at least once a month. Replace any faulty front-end components every three months. Check the shocks and struts every three months.