Mercedes-Benz 2009 R-Class, Operator'S Manual

Page: 278 / 412

Tires and wheels
276
Traction
Force exerted by the vehicle on the road via
the tires. The amount of grip provided.
Tread
The portion of a tire that comes into contact
with the road.
Treadwear indicators
Narrow bands, sometimes called “wear bars”
that show across the tread of a tire when only
1
/
16
in (1.6 mm) of tread remains.
TWR (Tongue Weight Rating)
Maximum permissible weight on trailer
tongue.
Uniform Tire Quality Grading Standards
A tire information system that provides
consumers with ratings for a tire’s traction,
temperature and treadwear. Ratings are
determined by tire manufacturers using U.S.
government testing procedures. The ratings
are molded into the sidewall of the tire.
Vehicle maximum load on the tire
Load on an individual tire that is determined
by distributing to each axle its share of the
maximum loaded vehicle weight and dividing
it by two.
Rotating tires
G
Warning!
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs.
rear), tire rotation is not possible.
G
Warning!
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque
of 110 lb-ft (150 Nm).
Only use genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.
Tire rotation can be performed on vehicles
with tires of the same dimension all around.
If your vehicle is equipped with tires of the
same dimension all around, tires can be
rotated, observing a front-to-rear rotation
pattern that will maintain the intended
rotation (spinning) direction of the tire
(
Y
page 255).
In some cases, such as when your vehicle is
equipped with mixed-size tires (different tire
dimension front vs. rear), tire rotation is not
possible.
If applicable to your vehicle’s tire
configuration, tires can be rotated according
to the tire manufacturer’s recommended
intervals in the tire manufacturer’s warranty
pamphlet located in your vehicle literature
portfolio. If none is available, tires should be
rotated every 3
000 to 6 000 miles (5 000 to
10 000 km), or sooner if necessary, according
to the degree of tire wear. The same rotation
(spinning) direction must be maintained.
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder wear
on front tires and tread center wear on rear
tires).
Thoroughly clean the mounting face of wheels
and brake disks, i.e. the inner side of the
wheels/tires, during each rotation. Check for
and ensure proper tire inflation pressure.
For information on wheel change, see “Flat
tire” (
Y
page 365).
Operation