Speed Rating -
The speed rating denotes the speed at which a tire is designed to be driven for
extended periods of time. The ratings range from 99 miles per hour (mph) to 186 mph. You may
not find this information on all tires because it is not required by law. These ratings are listed as
follows:
Speed Rating
Q
99 mph
T
118 mph
V
149 mph
R
106 mph
U
124 mph
W
168 mph*
S
112 mph
H
130 mph
Y
186 mph*
* For tires with a maximum speed capability over 149 mph, tire manufacturers sometimes use the
letters ZR. For those with a maximum speed capability over 186 mph, tire manufacturers always
use the letters ZR.
U.S. DOT Tire Identification Number
This begins with the letters “DOT” and indicates that the tire meets all federal standards. The next
two numbers or letters are the plant code where it was manufactured, and the last four numbers
represent the week and year the tire was built. For example, the numbers 3197 means the 31st
week of 1997. The other numbers are marketing codes used at the manufacturer’s discretion. This
information is used to contact consumers if a tire defect requires a recall.
Tire Ply Composition and Materials Used
The number of plies indicates the number of layers of rubber-coated fabric in the tire. In general,
the greater the number of plies, the more weight a tire can support. Tire manufacturers also must
indicate the materials in the tire, which include steel, nylon, polyester, and others.
Maximum Load Rating
This number indicates the maximum load in kilograms and pounds that can be carried by the tire.
Maximum Permissible Inflation Pressure
This number is the greatest amount of air pressure that should ever be put in the tire under
normal driving conditions.
1.5.9.2 UTQGS Information
Treadwear Number
This number indicates the tire’s wear rate. The higher the treadwear number is, the longer it
should take for the tread to wear down. For example, a tire graded 400 should last twice as long
as a tire graded 200.
Traction Letter
This letter indicates a tire’s ability to stop on wet pavement. A higher graded tire should allow
you to stop your car on wet roads in a shorter distance than a tire with a lower grade. Traction is
graded from highest to lowest as “AA”,”A”, “B”, and “C”.
Temperature Letter
This letter indicates a tire’s resistance to heat. The temperature grade is for a tire that is inflated
properly and not overloaded. Excessive speed, underinflation or excessive loading, either
separately or in combination, can cause heat build-up and possible tire failure. From highest to
lowest, a tire’s resistance to heat is graded as “A”, “B”, or “C”.
1.5.9.3 Additional Information on Light Truck Tires
Tires for light trucks have other markings besides those found on the sidewalls of passenger tires.
Please refer to the diagram below:
Tire Safety
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Summary of Contents for CONTRACTOR
Page 1: ...LOGAN COACH INC www LoganCoach com OWNER S MANUAL ...
Page 2: ......
Page 3: ...COWBOY ...
Page 6: ...Place in an envelope and mail to Logan Coach 2990 S 800 W Nibley UT 84321 ...
Page 25: ...Notes 20 ...