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Tire Size Designation
A tire's sidewall is marked with a tire
size designation. You will need this
information when selecting replace-
ment tires for your vehicle. The
following explains what the letters
and numbers in the tire size
designation mean.
(Example tire size designation)
P185/65R14 85S
P — Applicable vehicle type (tires
marked with the prefix "P" are
intended for use on passenger cars;
however, not all tires have this
marking).
185 — Tire width in millimeters.
65 — Aspect ratio. The tire's section
height as a percentage of its width.
R — Tire construction code (Radial).
14 — Rim diameter in inches.
85 — Load Index, a numerical code
associated with the maximum load
the tire can carry.
S — Speed Symbol. See the speed
rating chart in this section for
additional information.
Wheel Size Designation
Wheels are also marked with
important information that you need
if you ever have to replace one. The
following explains what the letters
and numbers in the wheel size
designation mean.
(Example wheel size designation)
1 4 x 5 J
14 — Rim diameter in inches.
5 — Rim width in inches.
J — Rim contour designation.
Tire Information
Tire Speed Ratings
The chart below shows many of the
different speed ratings currently
being used for passenger vehicle
tires. The speed symbol is part of the
tire size designation on the sidewall
of the tire. This symbol corresponds
to that tire's designed maximum safe
operating speed.
Technical Information
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