Wheel Alignment Basics
Many automobile owners think that wheel misalignment only causes pulling of the vehicle to one side or the other during driving. But more than just steering is affected when the wheels need to be adjusted and the car’s ride is only symptomatic of bigger problems that can be caused by this imbalance over time. When car wheels are not properly aligned, engine performance, tire wear, smoothness of the ride, and lifetime of varied components can all be adversely affected.
The longer a car is driven without proper attention to wheel alignment, the bigger the cost of repair will be when the issues are corrected. According to research, the average automobile is driven about 12,000 miles per year. If you drive your only slightly misaligned car that 12,000 miles without repair, the resulting wear on tires alone is the equivalent of the car dragging the tires sideways for over 68 miles. Fix your car’s alignment early and you can save your tires for continued wear. Ignore the problem and you will likely need to purchase a new set of tires and other parts, too.
For most car models, wheels should be realigned every 10,000 miles. There are several telltale signs indicating that your car may need wheel alignment:
- uneven or rapid tire wear
- steering pulls to one side
- car feels “loose” during driving
- vibrations in the steering wheel or column
- shimmying of the steering wheel
- steering wheel is not centered when the car is driving straight
- gas consumption per mile has increased
Whenever aligning your own wheels, remember that each automobile manufacturer’s directions must be followed to ensure safe and thorough repair. The automotive industry is rapidly changing, so depending upon the age, make, and model of your car, there could be very different requirements to ensure your wheels are aligned. Newer cars are implementing or already consist of four-wheel steering and very complex electronic suspensions with equally complex alignment issues. Also follow all of the guidelines for any equipment you use in the alignment process.
When preparing to talk to your mechanic about wheel alignment or to work on your car yourself, you will need to be familiar with several basic terms:
Camber is the number of degrees at which the wheel angles when viewed from the front of the vehicle. A positive camber is when the top of the wheel is leaning outward from the car’s center. This causes uneven tread wear on the outer edges of the tires and pulling of the car in one direction or another during driving. A negative camber is when the wheel is leaning toward the center of the car, causing the tires to wear on the treads closest to the car’s center. In cars with front wheel drive, camber is likely not adjustable. A camber issue on front wheel drive cars indicates a deeper issue or problem with other bent or worn parts that must be found and replaced.
Caster is the more difficult of wheel angles to understand. It is the angle of the wheels’ steering pivot when viewed from the side of the vehicle. Measured in degrees, if the pivot top of a wheel is leaning toward the car’s rear, the caster is positive. A forward-leaning pivot is negative.
When the caster is out of adjustment tire wear is not affected. But, the car will pull to one side or it will be difficult to keep the car going in a straight line. Many of today’s vehicles do not have adjustable caster. In four wheel drive cars an out of adjustment caster may indicate post-collision damage or other worn or bent parts.
Toe-In is a measurement in inch fractions that indicates the distance between the two parallel wheels’ tire fronts and tire backs. If the tires are exactly equidistant at the front of the wheels as they are between the backs of the two wheels, the toe-in is zero. When the fronts of the tires are closer together than the rear of the tires, it is a toe-in measurement. If the front of the tires are farther apart than the rear of the same wheels, the measurement is a toe-out. Incorrect toe-in causes a sawtooth wear pattern on both tires.
Beyond camber, caster, and toe-in, several other maintenance points will need to be checked during a wheel alignment, but these are the areas most obviously indicative of an alignment problem. Regardless of whether you are doing the wheel alignment yourself or using a certified mechanic, the first step and the last step are always a test drive to aid in determination of the car’s alignment.