What is it?

Essentially, alignment refers to the way your car's wheels are positioned. Ideally, your wheels should be parallel to each other and perpendicular to their axles and the road.  The least amount of rolling resistance, friction, and tire wear as well as the greatest traction are what results from proper wheel alignment.

BENEFITS OF PROPER ALIGNMENT MAY INCLUDE:

• Better gas mileage
• Longer lasting tires
• Easier steering
• Smoother ride
• Safer drive

QUESTIONS 

• Is your steering wheel straight when you are driving?
• Does your car pull to one side?
• Does your steering wheel vibrate?
• Do you notice uneven tire wear?
• Does your steering feel loose?
• Does your steering feel difficult to control?

Check your tires periodically.  A number of different things can affect your tires - from alignment to suspension components to improper inflation of tires.  If you recognize any of these symptoms, call to bring your car in for a free alignment inspection.  Alignment appointments are taken by appointment only!

3 Basic Alignment Angles

TOE:  The most important wheel alignment angle because it has the greatest effect on tire wear.  It refers to the parallelism between the wheels as viewed from above.  When both fron wheels are aimed straight ahead and the distance between the leading edges of both front tires is the same as the distance between the trailing edges, the wheels have zero toe and are aligned.  However, the alignment changes as the vehicle is driven.

The joints and sockets in the suspension and steering linkage all have some play.  When added together can allow wheel alignment to change depending on how the steering and suspension are loaded.  The rubber bushings in the control arms have some compliance and deflect slightly when vehicle accelerates, brakes, turns and cruises.  This can also affect the toe alignment and cause it to change.  To compensate for this, a little "toe-in" or "toe-out" may be added during alignment depending on if vehicle is front- or rear-wheel drive.

Toe-in:  The front edges of the tires are closer together than the rear edges.  Trucks and most rear-wheel drive vehicles have alignment specification that call for some toe-in.  This will result in a zero rolling toe because as the vehicle is being driven it has a natural tendency for the front and rear wheels to "toe-out" due to rolling resistance and compliance in the steering and suspension.

Toe-out:  The front edges of the tires are farther apart than the rear edges.  Worn tie rod ends or collapsed control arm bushings may cause this.  Toe-out is a bad condition as it causes the tires to scrub as they roll along.**Only 1/8th inch of toe-out will scrub the tires sideways 28 feet for every mile driven.

How to tell:  Feathered wear pattern across both front tires indicates toe misalignment and the direction of the feathering will tell you if it is toed-in or toed-out.  Rough edges towards the inside=toe-in.  Rough edges to the outside=toe-out.  Radial tires are different.  Wear of the outer rib=toe-in.  Wear of the inner rib=toe-out.**Underinflation will intesify the tire wear.

Replacing the tires does not replace the problem.  The toe needs to be reset to specifications before the problem will be fixed.  If your tires show toe wear, toe alignment needs to be checked as well as the steering needs to be inspected for worn or bent parts.  In addition to checking for loose or worn tie rod ends, look for bent steering arms or tie rods.

Some front-wheel drive cars and minivans may specify a slight amount of toe-out to compensate for toe-in that occurs as the front wheels pull the vehicle down the road.  Drive torque more than offsets the compliance in the steering and suspension allowing both front wheels to toe-in slightly when acceleration occurs.  This is what causes "torque steer", which is a sudden steering pull, in some front-wheel drive vehicles that have unequal length halfshafts.  Under hard acceleration, the left wheel with shorter halfshaft experiences more toe-in than the right wheel with the longer halfshaft.  The result is unequal toe changes and a steering pull to the right.  Vehicle manufacturers have reduced or eliminated torque steer in many front-wheel drive vehicles by using equal length halfshafts and/or stiffer control arm bushings. 

Rear toe is just as important as front toe--especially if the vehicle has an independent rear suspension or rear toe adjustments.  This includes most front-wheel drive cars and minivans as well as some rear-wheel drive cars.  Rear toe misalignment can cause toe wear on both the front and rear tires by creating a steering pull to one side.  Unlike front toe which is self-centering because of the steering linkage, a difference in rear toe angles side-to-side creates a "thrust angle".  The result is the same as rear axle misalignment that causes the vehicle to pull or lead to one side.

Question:  Why does this cause wear in the front tires?

Answer:  Front toe changes slightly anytime the wheels are steered to either side.  The inside wheel follows a shorter arc than the outside wheel, the steering arms are angled slightly so the wheels toe-out with respect to one another when the wheels are turned to one side.  The amount of toe-out is only a couple of degrees, but it helps to minimize scuffing and tire wear.  If the rear wheels are misaligned, though, and the driver has to constantly steer off-center to keep the vehicle going straight, it means the front wheels are constantly toed-out.  Over a period of time, this will cause toe wear to appear on the front tires. 

*Rear wheel drive cars and trucks that do not have independent rear suspensions have fixed rear toe settings, so no adjustments are possible.  But on most other vehicles rear to can be adjusted either by using factory adjustments or by installing aftermarket alignment aids such as toe/camber shims, offset bushings, etc.

CAMBER:  Refers to the tilt of the wheels as viewed from the front or rear.  Camber is the inward (negative) or outward (positive) tilt of the wheels.  Like toe, camber needs to be zero to be perfectly aligned.  However, it also changes as the vehicle is being driven.  When you drive over the bumps in the road, the up and down motions of the suspension change the geometry of the control arms and struts, which causes the camber to change.

If the camber is out, a tire will wear unevenly on one shoulder and the vehicle may pull toward the side with the most camber.  Camber usually only affects one wheel, so if only one tire shows unusual shoulder wear it is usually a problem with the camber misalignment.

Camber applies to both front and rear wheels, but only vehicles with independent rear suspensions will typically have camber specifications.  Most rear-wheel drive vehicles and trucks with solid axles do not have camber specifications because there's no way to change it. 

How to tell:  Excessive camber can be caused by a bent rear axle, bent spindle, mislocated strut tower, bent strut, worn or collapsed control arm bushing, bent control arm or a weak or broken spring.

CASTER:  The forward (negative) or rearward (positive) tilt of the steering axis as viewed from the side.  Only applies to the front wheels because they are the only ones that steer.  It effects steering stability, effort and return and does not have a direct effect on tire wear so it is often overlooked. 

Most vehicles have a small amount of positive caster to provide quick steering return and high speed stability.  Caster forces the spindle to angle down slightly as the wheels turn.  The chassis lifts and brings more weight to bear on the wheels as they turn.  Caster helps keep the wheels aimed straight ahead for improved steering stability, and helps the wheels return to the straight ahead position after turning.

How to tell:  If there is too much difference in caster side-to-side, it can cause a vehicle to drift or lead to one side.  The same problems that can cause camber misalignment can cause caster misalignment.  Ride height can alse affect the caster.  Spring sag or overloading a vehicle can alter ride height up to several inches, which can change caster readings by up to a degree or more.  This can contribute to steering instability or change steering effort.  So be sure to check the ride height.  If below specifications, weak springs should be replaced.  Upgrade opportunities are installing variable rate springs, air springs, overload shocks or air-assist shocks on vehicles used for towing or hauling heavy loads.