How to Align Wheels

Proper wheel alignment extends tire life.

Three wheel angles must be measured and adjusted in order to align wheels. The three angles are: the camber angle, which is the vertical angle of the wheels when viewed from the front, the caster angle, which is the angle of the steering pivot of each wheel when viewed from the side, and the toe angle, which is the difference in distance between the front and back of each pair of wheels. Measure and adjust each angle in that order for best results.

Things You'll Need

• 8 sheet metal squares
• Oil
• Jack
• 4 pieces plywood, 16 inches square, 3/4-inch thick
• Level
• Tape measure
• Shims
• Camber gauge
• Protractor
• Straight edge
• Thin aluminum sheet
• Metal shears
• Wrench
• Chalk

Instructions

1. 

   Oprtimal tire pressure set before alignment ensures accuracy.

   Add or release air from the tires for optimal pressure.

2. 

   Alignment plates are simple to make with oil and sheet metal.

   Make four simple alignment plates. To do that, divide eight sheet metal squares into pairs, and then smear oil between each pair.

3. 

   Lift a car on jacks only as high as necessary.

   Create wheel stands. Jack up the car and place one 16-inch-square, 3/4-inch-thick piece of plywood under each wheel. Place one alignment plate between each wheel and plywood square. Use a level, tape measure and shims to adjust all four wheel stands to equal, level height.

4. Lower the car onto the wheel stands.

5. Straighten the steering wheel.

6. Measure the camber angle using a camber gauge. To do this, turn the wheels so they point straight ahead. Then press the gauge against the side of one wheel and rotate the gauge knob until the level on it is centered. Each line on the knob represents a certain degree of camber. Clockwise turns represent positive camber, and counterclockwise turns represent negative camber. Mark the camber angle of each wheel on a sheet of paper. Complete this process for each wheel.

7. Create a simple gauge to measure 20-degree wheel turns. Begin by drawing an isosceles triangle with a peak angle of 20 degrees on a thin aluminum sheet. Use a protractor to create the 20-degree peak angle and a straight edge as a line guide. Cut out the triangle with metal shears.

8. Measure the camber angle of each wheel when turned in and out 20 degrees. With the wheels pointing straight ahead, mark a line on the floor next to each wheel with the straight edge. Keeping the straight edge lined up to the side of the tire, hold an angled edge of the simple gauge you created to the straight edge, and turn the tire until the base of the simple gauge lines up with the original mark on the floor. Measure the camber angle of the tire in this position with the camber gauge, and mark it down. Flip the triangular gauge so the straight base lines up with the straight edge, and turn the tire the other direction until an angled side of the triangle lines up with the floor line. Measure and mark the camber angle in this position. Complete this process for each tire.

9. Figure the caster angle for each wheel. Begin by calculating the difference in camber angle of each wheel when turned in and out. Multiply this difference by 1.5 to get the caster angle of each wheel.

10. Compare the camber and caster angles to ideal camber and caster angles. Check the car's owner's manual for the ideal angles.

11. Adjust wheels if necessary. Locate the camber/caster adjustment plates in the owner's manual. If it has no adjustment plates, adjust the camber angle using the strut bolts. To do this, loosen the strut bolts of each wheel, manually realign the tire to the correct camber angle, hold it in place and tighten the strut bolts. Check the new camber and new caster angles to see if further adjustment is necessary.

12. Measure the toe angles. Drive the car to a level surface, and park it with the wheels pointing straight ahead. Draw a horizontal line on the front of both front wheels at the same height with chalk. Check the distance between the two marks using the tape measure. Roll the car back until the chalk marks are at the back of the tires at the same height they were drawn. Measure the distance between the two tires at the back. Calculate the difference between the two to find the toe angle. Repeat the process with the back tires.

13. Change the toe angles if necessary. If the toe angles you found don't match the ideal toe angles in the car's owner's manual, you may change them by adjusting the tie rods.

Tips & Warnings

• Fixing the camber angle often fixes the caster and toe angles as well. Always check and adjust the camber angles first to avoid unnecessary adjustments.

• Never go under a car that is on jacks.

References

• AllPar: Do-It-Yourself Car Alignment
• Family Car Parts: A Short Course on Wheel Alignment
• Hot Rod: DIY Wheel Alignment Guide
• U.S. Department of Transportation, National Highway Traffic Safety Administration: Tire Safety