Front end alignment is also referred to as four wheel alignment. It is carried out to set a vehicle’s tires on the same horizontal direction. The process is also commonly referred to as four wheel alignment, since the rear-end tires are often aligned during the process. It is a complex process that involves the measurement of suspension angles and culminates in the adjustment of several suspension components.
If you are looking for information on how much your wheel alignment will cost, check out our front end alignment cost article here.
It is a critical suspension-tuning task whose primary goal is to ensure that a car’s tires operate as they should. It if often necessitated by the steering system and the suspension system not working as per their set angles, which in turn results in an out-of-alignment problem. However, this problem could also be caused by suspension wear or spring sag especially in older vehicles and rough driving habits such as hitting of curbs and potholes at speed, for vehicles of all ages.
Changes in the ride height of a vehicle have also been found to cause out-of-alignment problems. Suspension wear usually affects bushings and ball joints.
One of the most important reasons of carrying out correct vehicle wheel alignment is to avoid the rapid wear of tires goes hand-in-hand with bad wheel alignment. Front end alignment should be carried out on the following occasions:
- Whenever unusual wear patterns of the tires are detected.
- When new suspension components or tires are tires installed.
- Whenever the vehicle encounters a major road mishap or hazard.
Apart from front-end alignment, there are other two major types of alignments, these are: thrust angle and four-wheel alignments. Although front-end alignment is commonly referred to as four wheel alignment, some motoring experts prefer to separate the two. The principal operation in a front-end alignment process is the measurement and adjustment of the angles critical for the proper functioning of the front axle tires. This type of wheel alignment is ideal for vehicles which have a solid rear axle. In such a vehicle, the front tires should be positioned directly in line with the rear tires.
According to the Department of Motor Vehicles (DMV), vehicle alignment should be done when a vehicle is carrying its usual or typical load, for instance, sales samples of a product for drivers who do sales, or the driver’s own weight for autocross vehicles. This is meant to ensure that the influence of the typical load is factored in during the alignment process. The following suspension angles are the primary angles that are measured and adjusted during wheel alignment:
- Thrust angle.
- Toe angle.
- Camber angle.
The camber angle gives the deviation of the tire from the vertical. It can be visually inspected by looking at the tires from the back or the front of the vehicle while standing, or squatting, a few paces away from it. This angle is given in terms of degrees and is negative when the tire top tilts towards the body of the vehicle and positive when it leans away from the vehicle’s body. Street suspensions are, unfortunately, not able to compensate fully for the outer tipping of a car’s tires during hard cornering or even remain vertical during normal driving.
Camber angle is also influenced by the varying driving styles of most drivers. Enthusiastic drivers who corner at higher speeds are guaranteed of longer life for their tires as well as enhanced cornering grip. More cautious drivers, on the other hand, often have the inside edges of their car tires wearing off much faster than the outer part especially if the car has a negative camber. Excessive camber results in the loss of straight-line grip which is vital during hard stops and acceleration.
Caster angle is another static suspension angle that can be visually inspected by viewing a vehicle’s tires from the side. A line originating from the upper pivot point of the steering system to the lower part of the same system is used to determine the caster angle against a perpendicular line that is drawn to the ground.
The angle is positive if the line running through the upper and lower pivot points of the steering system slopes to the rear at the top and negative if it slopes to the front at the top. Caster angles are critical in ensuring that the manufacturer of a vehicle is able to balance stability at high speeds, steering effort and effective cornering at the front end.
The toe angle gives the general direction of a car tires against its centerline when viewed from the top. It can either be expressed in the form of inch fractions or degrees. Imaginary lines that cut across the tire centerlines are used to determine whether the toe angle is positive or negative. Rear-wheel drive vehicles make use of positive toe-in to make up for the frontal push of the rear wheels while front-wheel drive vehicles compensate for the pulling effect of the frontal wheels through the use of negative toe-out. Front end alignment is currently carried out using advanced state of the art equipment which stores critical data for future reference.