Wheels and tires, All about wheels and tires – Mercedes-Benz SL-Class 2015 User Manual

Page 583

Advertising
background image

Permissible gross vehicle weight: the

gross weight of the vehicle, all passengers

and the load must not exceed the permissible

gross vehicle weight.
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 and the load) 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: treadwear grade :,

traction grade ; and temperature grade =.

These regulations do not apply to Canada.

Nevertheless, all tires sold in North America

are provided with the corresponding quality

grading markings on the sidewall of the tire.
Where applicable, the tire grading informa-

tion can be found on the tire sidewall between

the tread shoulder and maximum tire width.

Example:

R

Treadwear grade: 200

R

Traction grade: AA

R

Temperature grade: A

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, ser-

vice practices and differences in road char-

acteristics 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 a wet surface as

measured under controlled conditions on

specified government test surfaces of asphalt

and concrete. A tire marked C may have poor

traction performance.

All about wheels and tires

581

Wheels

and

tires

Z

Advertising