How Do I Diagnose A Tire Pull?

Tires are manufactured by assembling components made of rubber, fabric cord and steel wire that are cured together in a mold. Under intense heat and pressure during the curing process, the rubber reaches a near liquid state before vulcanization takes place finalizing the tire's exact size, structure and shape.

If a tire's internal components are misaligned as it cures, it is possible that unequal internal forces may cause the vehicle to pull to the side, even when it is steered straight ahead. When this occurs with a brand new tire it is typically due to conicity, a manufacturing glitch where a tire's tread has cured slightly cone shaped rather than in the desirable uniform cylinder shape.

A tire that has conicity due to a manufacturing error will be apparent right after installation or immediately following the first time the tires are rotated. Because of this, tire manufacturers warranties only cover this condition early in the tire's life.

If tire pull first becomes noticeable after many miles of driving on a tire, it is typically due to driving conditions or vehicle misalignment that has caused the tire's tread to wear on an angle (with one side wearing faster than the other), or allowed the tire on the left side of the axle to wear faster than the tire on the right side of the same axle.

If a vehicle has a pulling problem, the alignment should be checked (including cross camber, cross caster and thrust angle settings). If the alignment is at the manufacturer's preferred settings or appropriately within the range, the following procedure can be used to confirm which tire is causing the pull.

The following steps must be used to isolate a pulling tire. Click here for a downloadable version of these instructions.

Step 1

Action to be Taken

Rotate the two front tires from side-to-side. Directional tires can be moved from side-to-side for testing purposes. The short time that they are on the vehicle backwards will not harm the tire.

Results

1. If the vehicle pulls in the opposite direction, the defective tire is one of the front tires.
   (GO TO STEP 2)
2. If the vehicle pulls in the same direction the problem is either with one of the rear tires or is not a tire-related problem.
   (GO TO STEP 3)

Step 2

Action to be Taken

Rotate the front tire on the side of the car that is in the direction of the pull, to the rear of the car.

Results

1. If the pull no longer exists or diminishes greatly, the tire that was moved to the rear of the car is the defective tire.
2. If the pulling does not change, the defective tire is isolated to the front tire that was not moved in Step 2.

Step 3

Action to be Taken

Rotate the two rear tires from side to side.

Results

1. If the vehicle pulls in the opposite direction, the defective tire is one of the rear tires.
   (GO TO STEP 4)
2. If the pulling tire does not change, the problem is not tire related. The car should be checked for possible misalignment or suspension wear.

Step 4

Action to be Taken

Rotate the rear tire on the side of the car that is in the direction of the pull to the front of the car.

Results

1. If the vehicle pull becomes more severe, the defective tire is isolated to the tire that was rotated to the front of the car.
2. If the pulling does not change, the defective tire is isolated to the rear tire that was not rotated.

A tire diagnosed as a pulling tire is a manufacturer's defect. The tire is covered under warranty only during the first 25% of tread wear. The defect is caused by the belts being incorrectly aligned during manufacture.