Tire Tech: WHEEL ALIGNMENT
Why Perform Wheel Alignments?
Reduced Tire Wear
Improper alignment is a major cause of premature tire wear. Over the years, a properly aligned vehicle can add thousands of miles to tire life.
Better Gas Mileage
Gas mileage increases as rolling resistance decreases. Total alignment sets all four wheel parallel which, along with proper inflation, minimizes rolling resistance.
Improved Handling
Does your car pull to one side? Does the steering wheel vibrate? Do you constantly have to move the steering wheel to keep your car traveling straight ahead? Many handling problems can be corrected by total alignment. With all the system components aligned properly, road shock is more efficiently absorbed for a smoother ride.
Safer Driving
A suspension system inspection is part of our alignment procedure. This allows us to spot worn parts before they cause costly problems.
Alignment Basics
In a nutshell, 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. There are four factors involved in setting the alignment to specification: caster, camber, toe, and thrust. The following brief discussion of each aspect will help you understand each factor and assist you in spotting potential problems.
Improper alignment is a major cause of premature tire wear. Over the years, a properly aligned vehicle can add thousands of miles to tire life.
Better Gas Mileage
Gas mileage increases as rolling resistance decreases. Total alignment sets all four wheel parallel which, along with proper inflation, minimizes rolling resistance.
Improved Handling
Does your car pull to one side? Does the steering wheel vibrate? Do you constantly have to move the steering wheel to keep your car traveling straight ahead? Many handling problems can be corrected by total alignment. With all the system components aligned properly, road shock is more efficiently absorbed for a smoother ride.
Safer Driving
A suspension system inspection is part of our alignment procedure. This allows us to spot worn parts before they cause costly problems.
Caster
Caster is the tilting of the uppermost point of the steering axis either forward or backward (when viewed from the side of the vehicle). A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering but does not affect the tire wear and is not adjustable on this vehicle. Caster is affected by the vehicle height, therefore it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging rear spring will affect caster. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel return-ability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster.
Camber
Camber is the tilting of the wheels from the vertical when viewed from the front of the vehicle. When the wheels tilt outward at the top, the camber is positive (+). When the wheel tilts inward at the top, the camber is negative (-). The amount of tilt is measured in degrees from the vertical. Camber settings influence the directional control and the tire wear.
Too much positive camber will result in premature wear on the outside of the tire and cause excessive wear on the suspension parts.
Too much negative camber will result in premature wear on the inside of the tire and cause excessive wear on the suspension parts.
Unequal side-to-side camber of 1° or more will cause the vehicle to pull or lead to the side with the most positive camber.
Toe
Toe is a measurement of how much the front and/or rear wheels are turned in or out from a straight-ahead position. When the wheels are turned in, toe is positive (+). When the wheels are turned out, toe is negative (-). The actual amount of toe is normally only a fraction of a degree. The purpose of toe is to ensure that the wheels roll parallel. Toe also serves to offset the small deflections of the wheel support system that occur when the vehicle is rolling forward. In other words, with the vehicle standing still and the wheels set with toe-in, the wheels tend to roll parallel on the road when the vehicle is moving. Improper toe adjustment will cause premature tire wear and cause steering instability.
Thrust Angle
The thrust angle is an imaginary line drawn perpendicular to the rear axle's centerline. It confirms if the rear axle is parallel to its front axle and that the wheelbase on both sides of the vehicle is the same. It also compares the direction that the rear axle is aimed with the centerline of the vehicle.
How to fix thrust angle
Solid rear axle: It often requires a trip to the frame straightening shop to correctly reposition the rear axle.
Independent rear axles
The toe-in or toe-out on both sides of the axle, or may have toe-in on one side and toe-out on the other side. The suspension on each side of the vehicle must be adjusted individually until it has reached the appropriate toe settings for its side of the vehicle.
Solid rear axle: It often requires a trip to the frame straightening shop to correctly reposition the rear axle.
Independent rear axles
The toe-in or toe-out on both sides of the axle, or may have toe-in on one side and toe-out on the other side. The suspension on each side of the vehicle must be adjusted individually until it has reached the appropriate toe settings for its side of the vehicle.
