Mount chains as tightly as you can and make sure that they do not touch the
brake lines or suspension.
Traction devices that are the wrong size or improperly installed can damage
your vehicle’s brake lines, suspension, body, and wheels. Stop driving if they
are hitting any part of the vehicle.
Using the wrong chains, or not properly installing chains, can damage the
brake lines and cause a crash in which you can be seriously injured or
killed.
Follow all instructions in this guide regarding the selection and use of tire
chains.
Tire Labeling
The tires that came on your vehicle have a number of markings. Those you
should be aware of are described below.
Here is an example of what each marking means:
P235/60R18 102T
• P: tire type (passenger vehicle)
• 235: tire width in millimeters
• 60: aspect ratio (tire section height as a
percentage of its width)
• R: tire construction code (radial)
• 18: rim diameter in inches
• 102: load index (code indicating
maximum load tire can carry)
• T: speed symbol (code indicating maximum speed rating)
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Tire Identification Number (TIN)
The tire identification number (TIN) is a
group of numbers and letters that look
like the following example. The TIN is
located on the sidewall of the tire.
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Glossary of Tire Terminology
Cold Tire Pressure – The tire air pressure when the vehicle has been parked
for at least three hours or driven less than 1 mile (1.6 km).
Load Rating – The maximum load that a tire is rated to carry for a given
inflation pressure.
Maximum Inflation Pressure – The maximum tire air pressure that the tire
can hold.
Maximum Load Rating – The load rating for a tire at the maximum
permissible inflation pressure for that tire.
Recommended Inflation Pressure – The cold tire inflation pressure
recommended by the manufacturer.
Treadwear Indicators (TWI) – The projections within the principal grooves
designed to give a visual indication of the degrees of wear of the tread.
DOT Tire Quality Grading
The tires on your vehicle meet all U.S. Federal Safety Requirements. All tires are
also graded for treadwear, traction, and temperature performance according to
Department of Transportation (DOT) standards. These gradings are explained
below.
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Uniform Tire Quality Grading
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
All passenger car tires must conform to Federal Safety Requirements in
addition to these grades.
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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 one-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,
however, and may depart significantly from the norm due to variations in
driving habits, service practices, and differences in road characteristics
and climate.
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