CAUTION!
Proper operation of four-wheel drive ve-
hicles depends on tires of equal size, type
and circumference on each wheel. Any
difference in tire size can cause damage to
the power transfer unit. Tire rotation
schedule should be followed to balance
tire wear.
DEPARTMENT OF
TRANSPORTATION
UNIFORM TIRE QUALITY
GRADES
The following tire grading categories
were established by the National High-
way 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 con-
form to Federal safety requirements in
addition to these grades.
Treadwear
The Treadwear grade is a comparative
rating, based on the wear rate of the
tire when tested under controlled con-
ditions 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 rela-
tive performance of tires depends
upon the actual conditions of their
use, however, and may depart signifi-
cantly from the norm due to variations
in driving habits, service practices,
and differences in road characteristics
and climate.
Four Wheel Drive (4WD) Tire Rotation
215