Lead/pull is the deviation of the vehicle from a straight path on a level road with no pressure on the steering wheel. Lead is usually caused by:
| • | Incorrect alignment |
| • | Uneven brake adjustment |
| • | Tire construction |
The way in which a tire is built can produce lead/pull in the vehicle. Off-center belts on radial tires can cause the tire to develop a side force while the vehicle rolls straight down the road. If one side of the tire has even a little larger diameter than the diameter of the other side, the tire will tend to roll to one side. Unequal diameters will cause the tire to develop a side force which can produce vehicle lead/pull.
The radial lead/pull diagnosis table should be used to determine whether the problem originates from an alignment problem or from the tires. Part of the lead diagnosis procedure calls for tire rotation that is different from the proper tire rotation pattern. If a medium-to-high mileage tire is moved to the other side of the vehicle, be sure to check for ride roughness. Rear tires will not cause lead/pull.
Step | Action | Yes | No |
|---|---|---|---|
1 |
Does the vehicle lead/pull? | Go to Step 2 | System OK |
2 |
Does the vehicle lead/pull? | Go to Step 3 | System OK |
3 | Check the front wheel alignment. Is the alignment within specifications? | Go to Step 5 | Go to Step 4 |
4 | Perform the front wheel alignment adjustment. Is the adjustment complete? | Go to Step 5 | -- |
5 | Compare the front camber and front caster to specifications. Are they within specifications? | Go to Step 8 | Go to Step 6 |
6 | Check the vehicle frame. Is the frame bent? | Go to Step 7 | Go to Step 1 |
7 | Straighten the frame. Is the repair complete? | Go to Step 3 | -- |
8 |
Does the vehicle still lead/pull? | Go to Step 10 | Go to Step 9 |
9 | Switch the left front tire and wheel assembly with the left rear tire and wheel assembly and replace the left front tire. Is the repair complete? | System OK | Go to Step 1 |
10 |
Does the vehicle still lead/pull? | Go to Step 1 | Go to Step 11 |
11 | Switch the right front tire and wheel assembly with the right rear tire and wheel assembly and replace the right front tire. Is the repair complete? | System OK | Go to Step 1 |
