SERVICING AND MAINTENANCE
425
T
IRE
R
OTATION
R
ECOMMENDATIONS
Tires on the front and rear axles of vehicles
operate at different loads and perform different
steering, driving, and braking functions. For these
reasons, they wear at unequal rates.
These effects can be reduced by timely rotation of
tires. The benefits of rotation are especially
worthwhile with aggressive tread designs such as
those on all season type tires. Rotation will
increase tread life, help to maintain mud, snow
and wet traction levels and contribute to a smooth,
quiet ride.
For the proper maintenance intervals
364.
More frequent rotation is permissible if desired.
The reasons for any rapid or unusual wear should
be corrected prior to rotation being performed.
The suggested rotation method is the “rearward
cross” shown in the following diagram. This
rotation pattern does not apply to some directional
tires that must not be reversed.
Tire Rotation (Rearward Cross)
DEPARTMENT OF TRANSPORTATION
UNIFORM TIRE QUALITY GRADES
The following tire grading categories
were established by the National
Highway Traffic Safety Administration.
The specific grade rating assigned by the
tire's manufacturer in each category is
shown on the sidewall of the tires on
your vehicle.
All passenger vehicle tires must conform
to Federal safety requirements in
addition to these grades.
T
READWEAR
The Treadwear grade is a comparative
rating, based on the wear rate of the tire
when tested under controlled conditions
on a specified government test course.
For example, a tire graded 150 would
wear one and one-half times as well on
the government course as a tire graded
100. The relative performance of tires
depends upon the actual conditions of
their use, however, and may depart
significantly from the norm due to
variations in driving habits, service
practices, and differences in road
characteristics and climate.
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