Understanding Your Vehicle Alignment

So you have just taken your car to your local garage for a wheel alignment. Your car is done, you paid the bill, and they hand you a receipt and a piece of paper. The paper has positive and negative numbers and words like caster, camber, and toe. What do they all mean? They are the specs of your wheel alignment from before and after. The first thing to remember is that the left and right sides of the vehicle are always considered from the drivers' perspective from inside the vehicle. Simply meaning the drivers side is the left and the passenger side is the right.

What is the Camber? The camber of your vehicle is the vertical tilt that the wheels have. When looking at your vehicle from the front your tires should be straight up and down. Positive Camber is caused when the bottoms of the tires are closer together than the top. This will also create wear on the outside edge or your tire. Negative Camber is when the tops of your tires are closer together than the bottom. This will cause wear on the inside edge of your tires. If the camber is out of the specified range for you vehicle you may also notice a change in the steering and drivability of your car. This is because when the wheels are within the specified range the maximum amount of tread is touching the road. When you have negative or positive camber the wheel is tilted taking some of that away.

What is the Toe? The Toe of your vehicle is the front to back tilt of a tire. When you are looking at your vehicle from the front, your tires should be pointed straight ahead. When the front of the tire is pointed inwards it is considered toe in or to have positive toe. When the front of the tire is pointed outward it is considered toe out or to have negative toe. Negative toe will cause tire wear on the inside edge of your tires and positive toe will cause wear on the outside edge of your tires.

What is the Caster? Caster is a little harder to explain because you cannot see it. The caster is the alignment of the upper and lower ball joints. If the upper ball joint is tilted back, further than the lower ball joint this is positive caster. If the lower ball joint is tilted back, further than the upper ball joint this is negative caster. What this does is causes the weight of the vehicle to be distributed to the correct area of the tire according to the manufacturer. Neither positive nor negative caster will cause tire wear, in fact most all vehicle specifications call for the vehicle to have a positive caster.