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Amarok 2011 ➤ , Caddy 2004 ➤ , Caddy 2011 ➤ , Caddy Kasten/Kombi 1996 ➤ ...
Wheels and Tyres Guide - Edition 01.2011
Exaggerated for clarity.
1 - Offset of belt and tread
F1 - Unequal vertical wheel forces
F2 - Unequal vertical wheel forces
Fk - Conicity force
The offset produces differences in stiffness at the inner and outer
shoulders of the tyre, resulting in differing vertical wheel forces.
Consequently the belt or tread will not be pressed onto the road
surface with the same force (F1, F2). A conical, or tapered, shape
develops. The resulting force (conicity force Fk) can, depending
on the speed, become so great that the vehicle then pulls to one
side.
If the force Fk on one wheel of the axle is, for example, 50 Newton,
and also 50 Newton on the other wheel, and both forces are ex‐
erted in the same direction, the forces are cumulated. Reversing
a tyre on the rim can compensate for the lateral pull because the
forces then act in opposite directions.
Because the direction in which the force of taper is exerted is not
visible, only road tests and strategic rotation of wheels and tyres
can establish which tyres cause the pulling.
The tyre consists of numerous components and materials which
are vulcanised to form a single part at the end of a complicated
manufacturing process. The result is differing production toleran‐
ces which make themselves noticeable through more or less
strong lateral forces (conicity forces). These forces can also occur
in new tyres.
Pulling to one side on front axle
Pulling to one side can be caused by the running gear. However,
experience shows that in 90% of all complaints, the tyres cause
pulling to one side.
Pulling to one side during normal driving
On a straight, level road surface, the vehicle wants to pull to one
side at a constant speed or with moderate acceleration. Force can
be felt at the steering wheel.
Pulling to one side during fast acceleration
Pulling to one side during fast acceleration is, in part, due to the
basic design of vehicles with front wheel drive. Different friction
levels at the left and right wheels or possible irregularities in the
road surface (potholes) and consequently varying road adhesion
have a substantial influence on the handling characteristics. This
does not constitute a complaint which is covered by the warranty.
4.5.3
Remedies when vehicle pulls to one
side
Test conditions before and during the road test:
– Check all suspension components on the front and rear axles
for damage.
– Check tyre pressure and correct if necessary.
– Check the tyres for external damage. Punctures, cuts, bubbles
on the sidewalls, flat spots from braking and/or damage to the
tread.
– Ask the customer if the tyre had been damaged by a nail or
similar object and was repaired by a tyre dealer. It may be
necessary to renew such tyres.
4. Facts about wheels and tyres (commercial vehicles)
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English 
