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SIENNA_OM_01999-08001_(U)
9-1. Specifications
This information has been prepared in accordance with regulations
issued by the National Highway Traffic Safety Administration of the
U.S. Department of Transportation.
It provides the purchasers and/or prospective purchasers of Toyota
vehicles with information on uniform tire quality grading.
Your Toyota dealer will help answer any questions you may have as
you read this information.
■DOT quality grades
All passenger vehicle tires must conform to Federal Safety
Requirements in addition to these grades. Quality grades can be
found where applicable on the tire sidewall between tread shoulder
and maximum section width.
For example: Treadwear 200 Traction AA Temperature A
■Treadwear
The treadwear grade is a comparative rating based on the wear
rate of the tire when tested under controlled conditions on a speci-
fied government test course.
For example, a tire graded 150 would wear one and a half (1-1/2)
times as well on the government course as a tire graded 100.
The relative performance of tire s depends upon the actual condi-
tions of their use. Performance may differ significantly from the norm
due to variations in driving habits , service practices and differences
in road characteristics and climate.
■Traction AA, A, B, C
The traction grades, from highest to lowest, are AA, A, B and C,
and they represent the tire’s ability to stop on wet pavement as
measured under controlled conditio ns on specified government test
surfaces of asphalt and concrete.
A tire marked C may have poor traction performance.
Warning: The traction grade assigned to this tire is based on braking
(straight ahead) traction tests and does not include cornering (turn-
ing) traction.
Uniform Tire Quality Grading
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SIENNA_OM_01999-08001_(U)
6139-1. Specifications
9
Vehicle specifications
RimA metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated
Rim diameter
(Wheel diameter) Nominal diameter of the bead seat
Rim size designation Rim diameter and width
Rim type designation The industry manufacturer’s designation for a
rim by style or code
Rim width Nominal distance between rim flanges
Vehicle capacity
weight (Total load
capacity) The rated cargo and luggage load plus 150 lb.
(68 kg) times the vehicle’s designated seating
capacity
Vehicle maximum load
on the tire The load on an individual tire that is deter-
mined by distributing to each axle its share of
the maximum loaded vehicle weight, and
dividing by two
Vehicle normal load
on the tire The load on an individual tire that is deter-
mined by distributing to each axle its share of
curb weight, accessory weight, and normal
occupant weight (distributed in accordance
with Table 1
* below), and dividing by two
Weather side The surface area of the rim not covered by the
inflated tire
Bead The part of the tire that is made of steel wires,
wrapped or reinforced by ply cords and that is
shaped to fit the rim
Bead separation A breakdown of the bond between compo-
nents in the bead
Bias ply tire A pneumatic tire in which the ply cords that
extend to the beads are laid at alternate
angles substantially less than 90 degrees to
the centerline of the tread
Carcass The tire structure, except tread and sidewall
rubber which, when inflated, bears the load
Chunking The breaking away of pieces of the tread or
sidewall
Cord The strands forming the plies in the tire
Tire related termMeaning
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SIENNA_OM_01999-08001_(U)
6159-1. Specifications
9
Vehicle specifications
Open spliceAny parting at any junction of tread, sidewall,
or innerliner that extends to cord material
Outer diameter The overall diameter of an inflated new tire
Overall width The linear distance between the exteriors of
the sidewalls of an inflated tire, including ele-
vations due to labeling, decorations, or protec-
tive bands or ribs
Passenger car tire A tire intended for use on passenger cars,
multipurpose passenger vehicles, and trucks,
that have a gross vehicle weight rating
(GVWR) of 10,000 lb. or less
Ply A layer of rubber-coated parallel cords
Ply separation A parting of rubber compound between adja-
cent plies
Pneumatic tire A mechanical device made of rubber, chemi-
cals, fabric and steel or other materials, that,
when mounted on an automotive wheel, pro-
vides the traction and contains the gas or fluid
that sustains the load
Radial ply tire A pneumatic tire in which the ply cords that
extend to the beads are laid at substantially 90
degrees to the centerline of the tread
Reinforced tire A tire designed to operate at higher loads and
at higher inflation pressures than the corre-
sponding standard tire
Section width The linear distance between the exteriors of
the sidewalls of an inflated tire, excluding ele-
vations due to labeling, decoration, or protec-
tive bands
Sidewall That portion of a tire between the tread and
bead
Sidewall separation The parting of the rubber compound from the
cord material in the sidewall
Tire related termMeaning