Volkswagen Tiguan Service and Repair Manual: Vehicle Pulls to One Side

General Information

Perform a road test to determine if a vehicle pulls to one side and if so, when and to which side. If the vehicle pulls to one side.

If the vehicle alignment is measured, submit the measurement printout and the complaint report with the tire.

Manufacturer's tolerances can lead to taper in the tire construction. This results in a side force when the tire rolls, which acts directly on the suspension and can therefore lead to vehicle self-steering behavior. Targeted rotation of the wheels can balance out this self-steering behavior.

Taper

Taper is caused by slightly offsetting the tread and/or the belt by a few tenths of a millimeter from the geometric center of the tire. Taper cannot be recognized visually nor can it be measured with workshop equipment.

Components of a Tire

1. Bead
2. Shoulder
3. Tread
4. Steel belt

1. Geometric center of tire
2. Actual position of belt. It can be offset to inside or outside.

Shown out of proportion to provide a better illustration.

1. Belt/tread offset

F1 - Unequal forces on contact patch

F2 - Unequal forces on contact patch

Fk - Force of taper

The offset produces differences in rigidity of the inner and outer shoulders of the tire, which lead to differing forces on the contact patch. Due to this, the belt and tread will not be pressed against the road surface with the same force (F1, F2). A taper forms. The resulting force (force of taper Fk) can become so large depending on speed, that the vehicle pulls to one side.

If the force (Fk) on one wheel of the axle is, for example, 50 Newton and on the other wheel also 50 Newton, and both forces are exerted in the same direction, the forces are additive. Reversing a tire on the rim can compensate for the pulling because the forces then act against each other.

Because the direction in which the force of taper is exerted is not visible at the tire, only road tests and targeted rotation of wheels and tires can establish which tires cause the pulling.

The tire consists of numerous components and materials which are vulcanized to a single part at the end of a complicated manufacturing procedure. This leads to differing construction tolerances which can make themselves noticeable through more or less strong lateral forces (lateral forces of taper). These forces can also develop in new tires.

One-Sided Pulling on Front Axle

Pulling to one side can be caused by the suspension. However, experience shows that in 90% of all complaints, the tires cause pulling to one side.

One-Sided Pulling During Normal Driving Style

On a straight, level road surface, the vehicle wants to pull to one side at a constant speed or with moderate acceleration. A force can be felt at the steering wheel.

One-Sided Pulling During Strong Accelerating

Pulling to one side during fast acceleration is, in part, due to the design of vehicles with front wheel drive. Various frictional conditions of left and right wheels, for example, possible irregularities in the road surface (pot holes) and consequently varying adhesion to ground have a substantial influence on the handling characteristics. This does not constitute a complaint in the sense of warranty coverage.

Corrective Action When Vehicle Pulls to One Side

Test Conditions Before and During the Road Test

• Check all suspension components on front and rear axle for damage.
• Check tire pressure and correct if necessary.
• Check the tires for external damage. Holes, cuts, bulges in the side wall, flat spots from braking and/or damage to the tread.
• Ask the customer if a tire had been damaged by a nail or similar object and perhaps repaired by a tire dealer. You may have to replace such tires.
• Check tires for even wear and tread depth.
• Are all tires of the same type, manufacture and tread pattern?
• If the tires are non-directional, ensure that all DOT classifications on the tire face outwards. It may be that the vehicle's wheels and tires were already changed around at an earlier date.
• Are the tire brands factory recommended as initial equipment?
• For the road test, use a level, straight driving surface that does not slope off to one side and does not have ruts.
• Perform the road test with the customer under the conditions specified above. The customer should demonstrate the problem.

Note

There should not be any side wind when road test takes place.

If the complaint is justified, it is recommend to rotate the wheels and tires as described on the following pages.

Before beginning, observe the following notes, otherwise all effort will be for nothing!

Note

• Mark tires/wheels before the first rotation, e.g. LF, RF, LR, RR.
• After rotating wheels or reversing the tire on its rim, observe very carefully how the vehicle behaves during the road test. Note what was replaced and how.
• The intensity or any possible change to the one-sided pulling should be assessed.
• To do this, it is absolutely essential that the road tests are always performed by the same person on the same road. It is best to drive the "test course" in both directions.
• Replacing a tire with a new tire does not guarantee that pulling to one side will be eliminated. Therefore, it is recommended to perform a targeted exchange of the wheels as described below.
• If there are large differences in the tread depth of the tires on the front and rear axles, the tires with the deeper tread should always be mounted on the front axle.

Targeted Rotating of Wheels for Non-Directional Tires

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Perform a road test to determine if a vehicle pulls to one side and if so, when and to which side
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If the vehicle pulls to one side, swap the front wheels.
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Road Test, Performing
Vehicle travels straight - END
Vehicle pulls opposite		Vehicle pulls to the same side
↓		↓
Reverse one tire on its rim on the front axle (reverse the direction of travel)		Rotate wheels from front to back
↓		↓
Road Test, Performing		Road Test, Performing
Vehicle travels straight - END		Vehicle travels straight - END
Vehicle does not travel straight		Vehicle does not travel straight
↓		↓
Swap front wheels and swap back wheels		Vehicle pulls opposite	No change
↓		↓	↓
Road Test, Performing		Reverse one tire on its rim on the front axle (reverse the direction of travel)	Check alignment of front and rear axles, adjust if necessary.
Vehicle travels straight - END			If adjustment is correct, inform Product Support.
Vehicle does not travel straight
↓
Swap the front wheels
↓		↓
Road Test, Performing		Road Test, Performing
Vehicle travels straight - END	Vehicle does not travel straight	Vehicle travels straight END
	↓	Vehicle does not travel straight
	Install new tires on front axle	Install new tires on front axle
	↓	↓
	Road Test, Performing	Road Test, Performing
	Vehicle travels straight - END	Vehicle travels straight - END
	↓	↓
Vehicle does not travel straight, inform Product Support