367 Operation
Tires and wheels
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated.
Sidewall
The portion of a tire between the tread and
the bead.
TIN (T
ire I
dentification N
umber)
Unique identifier which facilitates efforts
by tire manufacturers to notify purchasers
in recall situations or other safety matters
concerning tires and gives purchases the
means to easily identify such tires. The TIN
is comprised of “Manufacturer’s identifica-
tion mark”, “Tire size”, “Tire type code”
and “Date of manufacture”.
Tire load rating
Numerical code associated with the
maximum load a tire can support.Tire ply composition and material used
This indicates the number of plies or the
number of layers of rubber-coated fabric in
the tire tread and sidewall. Tire manufac-
turers also must indicate the ply materials
in the tire and sidewall, which include
steel, nylon, polyester, and others.
Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is approved.
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 (T
ongue W
eight R
ating)
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
government testing procedures. The
ratings are molded into the sidewall of the
tire.
Vehicle capacity weight
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle’s
designated seating capacity.
506 Technical termsTIN
(Tire I
dentification N
umber)
(
page 367)
Tire load rating
(page 367)
Tire ply composition and material used
(page 367)
Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is ap-
proved.
Traction
Force exerted by the vehicle on the
road via the tires.Transfer case
Speed of rotation/torque converter
that works together with the ->auto-
matic transmission.
Tread
(
page 367)
Treadwear indicators
(page 367)
TWR
(Tongue W
eight R
ating)
The TWR is the maximum permissible
weight on the trailer tongue.Uniform Tire Quality Grading Standards
(
page 367)
Vehicle capacity weight
(page 367)
Vehicle level control*
The ground clearance of the vehicle is
automatically controlled according to a
selected setting and speed.The driver
can set the ground clearance manually
for example on very rough roads.
Vehicle maximum load on the tire
(page 368)
VIN
(Vehicle I
dentification N
umber)
The number set by the manufacturer
and placed on the body to uniquely
identify each vehicle produced.
