Downloaded from www.Manualslib.com manuals search engine If  you ever replace your tires with those  not having  a 
TPC Spec number, make  sure they  are the same  size, 
load  range, speed rating and construction  type (bias, 
bias-belted  or radial) as your original tires. 
Uniform  Tire  Quality  Grading 
The  following information  relates  to the system 
developed  by the United  States National Highway 
Traffic Safety Administration which  grades tires by 
treadwear, traction and  temperature performance. 
(This  applies only  to vehicles sold 
in the United  States.) 
Treadwear 
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  a half 
(1 1/2) 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. 
Traction - A, B, C 
The traction grades, from highest to lowest are: A, B, 
and C. They represent the  tire’s ability to stop on wet 
pavement as measured under  controlled conditions on 
specified government  test surfaces 
of asphalt and 
concrete.  A tire marked 
C may have poor traction 
performance. 
Warning:  The traction grade assigned 
to this tire  is based 
on braking (straight-ahead) traction tests and  does not 
include  cornering (turning) traction. 
6-40