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Alignment:
Angles of the tire
and suspension axes relative to each other and the ground:
caster, camber, toe. Also, the adjustment of components to
bring them into a predetermined position for the most efficient
operation of wheel and vehicle for proper even tire wear.
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Alpha-Numeric:
A load-based tire sizing
system containing the load capacity, type of tire construction,
aspect ratio, and the rim diameter in inches. |
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Aspect
Ratio:
The dimensional relationship
between tire section height and section width; section height
divided by section width. |
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Balance:
A uniform mass distribution
of a tire and wheel assembly about its axis of rotation. |
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Carrying
Capacity:
Amount of load that a tire can
carry at a given inflation pressure as established by the
Tire and Rim Association. |
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Casing
(Carcass):
The structure of tire
cords locked around wire beads, (most often used in relation
to worn tires). |
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Cold
Inflation:
The pressure in a tire
that has been driven less than 1 mile or has been standing
for three hours or more. |
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Compounding:
Refers to the mixture
of ingredients that go into the rubber used in a tire. Different
chemicals or types of compounds affect wear, traction, cut
resistance or other properties of a tire. |
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DOT:
A tire branding symbol
which denotes the tire meets requirements of the Department
of Transportation. |
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Grooving:
A tread cutting process
in which grooves of varying depths and angles are cut into
a tire's tread to improve forward traction, braking, or lateral
stability. |
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H-Rated:
A speed rating category
for tires which is used on vehicles with a top speed up to
130 mph. |
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Hydroplaning:
Loss of traction at
high speeds caused by a wedge of water which lifts a tire
off the road surface. |
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Load
Index:
A numerical code which
specifies the maximum load a tire can carry at the speed indicated
by its speed symbol, at maximum inflation pressure. |
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LT-Metric:
A sizing system using
the section width in millimeters, aspect ratio, type of construction,
and rim diameters in inches (e.g.: LT235/85R16). |
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LTP-Metric:
A new (1992) light
truck personal use sizing systems using the section width
in millimeters, aspect ratio, type of construction, and rim
diameters in inches (e.g.: LTP235/75R15). |
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M+S,
M/S or M & S:
A tire sidewall designation
indicating that the tire meets the RMA definition of a mud
and snow tire. |
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Metric
Tire Size System:
A tire sizing system
using the cross section in millimeters, aspect ratio, speed
category, tire construction and the rim diameter in inches
(e.g.: 185/70SR13). |
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Numeric
System:
A tire sizing system
using tire cross section width and rim diameter in inches
(e.g.: 7.35-14). |
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P-Metric
System:
A tire sizing system
using the section width in millimeters, aspect ratio, type
of tire construction, and rim diameter in inches (e.g.: P225/70R15). |
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Plies:
The layers of fabric
that make up the cord body of a tire. |
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Radial
Tire:
A tire built with casing
plies that cross the crown at an angle of 90 degrees. |
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Retread:
A used casing which
has new tread rubber applied to it. |
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Ribs:
The rubber elements
at the tire tread which contact the ground, oriented in a
generally circumferential direction. |
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Rim:
A component supporting the tire that contains inflation
pressure. It may be single piece or multi-piece. |
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S-Rated:
A speed rating
category for vehicles with a top speed up to 112 mph. |
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Series:
This is the part
of the size designation in tires which gives the ratio of
the height of a tire (from the rim to the top of the tread)
to the width of the tire (from sidewall to sidewall). It is
also referred to as the aspect ratio of a tire. |
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Shoulder:
Outer edges of
tire tread. |
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Sidewall:
The side of a
tire between the tread shoulder and the rim bead. |
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Speed
Rating System (Speed Category Markings):
An alphabetical
system describing a tire's capability to travel at established
and predetermined speeds. |
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T-Rated:
A speed rating
category for vehicles with a top speed up to 118 m.p.h. |
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Tread:
The grooved or
patterned exterior part of the tire that contacts the road
surface. |
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U-Rated:
A speed category
for a vehicle of a top speed up to 124 mph. |
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UTQG:
Uniform Tire
Quality Grade; a performance measurement of a tire, based
upon its test results in three categories: treadwear, traction,
and temperature resistance. |
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V-Rated:
A speed category
for vehicles with a top speed of more than 130 mph. Load index
V-speed rated capped at 149 mph. |
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Z-Rated:
A speed category
for a vehicle of a top speed of more than 149 mph. |
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Source
Credit: http://www.TireSafety.com (Brought to you by Bridgestone®/Firestone®) |
