Typical tire symbols
- Tire size
- DOT and Tire Identification Number (TIN)
- Location of treadwear indicators
- Tire ply composition and materials
Plies are layers of rubber-coated parallel cords. Cords are the strands
which form the plies in a tire.
- Uniform tire quality grading
For details, see "Uniform Tire Quality Grading" that follows.
- Load limit at maximum cold tire inflation pressure
- Maximum cold tire inflation pressure
This means the pressure to which a tire may be inflated.
- TUBELESS or TUBE TYPE
A tubeless tire does not have a tube and air is directly put into the
tire.
A tube type tire has a tube inside the tire and the tube maintains the air
pressure.
- Radial tires or bias-ply tires
A radial tire has "RADIAL" on the sidewall. A tire not marked "RADIAL"
is a bias-ply tire.
- Summer tire or all season tire
An all season tire has "M+S" on the sidewall. A tire not marked "M+S"
is a summer tire.
Typical DOT and Tire Identification Number (TIN)
Type A
Type B
- DOT symbol*
- Tire Identification Number (TIN)
- Tire manufacturer's identification mark
- Tire size code
- Manufacturer's optional tire type code (3 or 4 letters)
- Manufacturing week
- Manufacturing year
- Manufacturer's code
*: The DOT symbol certifies that the tire conforms to applicable Federal
Motor Vehicle Safety Standards.
Tire size
■ Typical tire size information
The illustration indicates typical
tire size.
- Tire use
(P = Passenger car,
T = Temporary use)
- Section width (millimeters)
- Aspect ratio
(tire height to section width)
- Tire construction code
(R = Radial, D = Diagonal)
- Wheel diameter (inches)
- Load index
(2 digits or 3 digits)
- Speed symbol
(alphabet with one letter)
■ Tire dimensions
- Section width
- Tire height
- Wheel diameter
Tire section names
- Bead
- Sidewall
- Shoulder
- Tread
- Belt
- Inner liner
- Reinforcing rubber
- Carcass
- Rim lines
- Bead wires
- Chafer
Uniform Tire Quality Grading
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 specified
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 tires depends upon the actual conditions
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 conditions 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 (turning)
traction.
■ Temperature A, B, C
The temperature grades are A (the highest), B, and C, representing
the tire's resistance to the generation of heat and its ability to dissipate
heat when tested under controlled conditions on a specified
indoor laboratory test wheel.
Sustained high temperature can cause the material of the tire to
degenerate and reduce tire life, and excessive temperature can lead
to sudden tire failure.
Grade C corresponds to a level of performance which all passenger
car tires must meet under the Federal Motor Vehicle Safety Standard
No. 109.
Grades B and A represent higher levels of performance on the laboratory
test wheel than the minimum required by law.
Warning: The temperature grades of a tire assume that it is properly
inflated and not overloaded.
Excessive speed, underinflation, or excessive loading, either separately
or in combination, can cause heat buildup and possible tire
failure.
Glossary of tire terminology
| Tire related term |
Meaning |
| Cold tire inflation pressure |
Tire pressure when the vehicle has been
parked for three hours or more, or has not
been driven more than 1 mile or 1.5 km under
that condition |
| Maximum inflation
pressure |
The maximum cold inflated pressure to which
a tire may be inflated, shown on the sidewall
of the tire |
| Recommended inflation
pressure |
Cold tire inflation pressure recommended by a
manufacturer |
| Accessory weight |
The combined weight (in excess of those standard
items which may be replaced) of automatic
transmission, power steering, power
brakes, power windows, power seats, radio
and heater, to the extent that these items are
available as factory-installed equipment
(whether installed or not) |
| Curb weight |
The weight of a motor vehicle with standard
equipment, including the maximum capacity of
fuel, oil and coolant, and if so equipped, air
conditioning and additional weight optional
engine |
| Maximum loaded vehicle
weight |
The sum of:
- Curb weight
- Accessory weight
- Vehicle capacity weight
- Production options weight
|
| Normal occupant
weight |
150 lb. (68 kg) times the number of occupants
specified in the second column of Table 1*
that follows |
| Occupant distribution |
Distribution of occupants in a vehicle as specified
in the third column of Table 1* below |
| Production options
weight |
The combined weight of installed regular production
options weighing over 5 lb. (2.3 kg) in
excess of the standard items which they
replace, not previously considered in curb
weight or accessory weight, including heavy
duty brakes, ride levelers, roof rack, heavy
duty battery, and special trim |
| Rim |
A 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 flange |
| 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 determined
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 determined
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 components
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 |
| Cord separation |
The parting of cords from adjacent rubber
compounds |
| Cracking |
Any parting within the tread, sidewall, or innerliner
of the tire extending to cord material |
| CT |
A pneumatic tire with an inverted flange tire
and rim system in which the rim is designed
with rim flanges pointed radially inward and
the tire is designed to fit on the underside of
the rim in a manner that encloses the rim
flanges inside the air cavity of the tire |
| Extra load tire |
A tire designed to operate at higher loads and
at higher inflation pressures than the corresponding
standard tire |
| Groove |
The space between two adjacent tread ribs |
| Innerliner |
The layer(s) forming the inside surface of a
tubeless tire that contains the inflating medium
within the tire |
| Innerliner separation |
The parting of the innerliner from cord material
in the carcass |
| Intended outboard
sidewall |
- The sidewall that contains a whitewall,
bears white lettering, or bears manufacturer,
brand, and/or model name molding
that is higher or deeper than the same
molding on the other sidewall of the tire, or
- The outward facing sidewall of an asymmetrical
tire that has a particular side that
must always face outward when mounted
on a vehicle
|
| Light truck (LT) tire |
A tire designated by its manufacturer as primarily
intended for use on lightweight trucks
or multipurpose passenger vehicles |
| Load rating |
The maximum load that a tire is rated to carry
for a given inflation pressure |
| Maximum load rating |
The load rating for a tire at the maximum permissible
inflation pressure for that tire |
| Maximum permissible
inflation pressure |
The maximum cold inflation pressure to which
a tire may be inflated |
| Measuring rim |
The rim on which a tire is fitted for physical
dimension requirements |
| Open splice |
Any 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 elevations
due to labeling, decorations, or protective
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 adjacent
plies |
| Pneumatic tire |
A mechanical device made of rubber, chemicals,
fabric and steel or other materials, that,
when mounted on an automotive wheel, provides
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 corresponding
standard tire |
| Section width |
The linear distance between the exteriors of
the sidewalls of an inflated tire, excluding elevations
due to labeling, decoration, or protective
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 |
| Snow tire |
A tire that attains a traction index equal to or
greater than 110, compared to the ASTM E-
1136 Standard Reference Test Tire, when
using the snow traction test as described in
ASTM F-1805-00, Standard Test Method for
Single Wheel Driving Traction in a Straight
Line on Snow-and Ice-Covered Surfaces |
| Test rim |
The rim on which a tire is fitted for testing, and
may be any rim listed as appropriate for use
with that tire |
| Tread |
That portion of a tire that comes into contact
with the road |
| Tread rib |
A tread section running circumferentially
around a tire |
| Tread separation |
Pulling away of the tread from the tire carcass |
| Treadwear indicators
(TWI) |
The projections within the principal grooves
designed to give a visual indication of the
degrees of wear of the tread |
| Wheel-holding fixture |
The fixture used to hold the wheel and tire
assembly securely during testing |
*: Table 1 - Occupant loading and distribution for vehicle normal load for
various designated seating capacities
| Designated seating
capacity, Number of
occupants |
Vehicle normal load,
Number of occupants |
Occupant distribution
in a normally loaded
vehicle |
| 2 through 4 |
2 |
2 in front |
| 5 through 10 |
3 |
2 in front, 1 in second
seat |
| 11 through 15 |
5 |
2 in front, 1 in second
seat, 1 in third seat,
1 in fourth seat |
| 16 through 20 |
7 |
2 in front, 2 in second
seat, 2 in third seat,
1 in fourth seat |
|
