Mercedes Benz 2009 M-Class User Manual

The treadwear grade is a comparative rat-
ing based on the wear rate of the tire when 
tested under controlled conditions on a 
specified government test course. For ex-
ample, a tire graded 150 would wear one 
and one-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.

The traction grades, from highest to low-
est, are AA, A, B, and C. Those grades rep-
resent 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 perfor-
mance.

The temperature grades are A (the high-
est), B, and C, representing the tire’s resis-
tance to the generation of heat and its 
ability to dissipate heat when tested under 
controlled conditions on a specified indoor 
laboratory test wheel. Sustained high tem-
perature can cause the material of the tire 
to degenerate and reduce tire life, and ex-
cessive temperature can lead to sudden 
tire failure. The grade C corresponds to a 
level of performance which all passenger 
car tires must meet under the Federal 
Motor Vehicle Safety Standard No. 109. 
Grades B and A represent higher levels of 
performance on the laboratory test wheel 
than the minimum required by law.

G

The traction grade assigned to this tire is 

based on straight-ahead braking traction 

tests, and does not include acceleration, 

cornering, hydroplaning, or peak traction 

characteristics.