All About Wheels And Tires; Traction; Tread Wear; Uniform Tire Quality Grading Standards - Mercedes-Benz SLS AMG Operator's Manual

Gross axle weight rating: the maximum per-
missible weight that can be carried by one
axle (front or rear axle).
To ensure that your vehicle does not exceed
the maximum permissible values (gross vehi-
cle weight and maximum gross axle weight
rating), have your loaded vehicle (including
driver, occupants, cargo, and full trailer load if
applicable) weighed on a suitable vehicle
weighbridge.

All about wheels and tires

Uniform Tire Quality Grading Stand-
ards
Overview of Tire Quality Grading Stand-
ards
Uniform Tire Quality Grading Standards are
U.S. government specifications. Their pur-
pose is to provide drivers with uniform relia-
ble information on tire performance data. tire
manufacturers have to grade tires using three
performance factors: tread wear :, tire trac-
tion ; and heat resistance =. All tires sold
in North America are provided with the cor-
responding quality class mark on the sidewall
of the tire, even though these regulations do
not apply to Canada.
Quality grades can be found, where applica-
ble, on the tire sidewall between the tread
shoulder and maximum tire width.
All about wheels and tires
Example:
Treadwear grade: 200
R
Traction grade: AA
R
Temperature grade: A
R
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. government 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, how-
ever, and may depart significantly from the
norm due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.

Traction

G WARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
! Avoid wheelspin. This can lead to damage
to the drive train.
The traction grades – from highest to lowest –
are AA, A, B and C. Those grades 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.
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