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. 

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.

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