Tire Information
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 car. The follow-
ing explains what the letters and
numbers in the tire size designation
mean.
(Example tire size designation)
P185/70R14 87S
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.
70
— Aspect ratio. The tire's section
height as a percentage of its width.
R
— Tire construction code (Radial).
14
— Rim diameter in inches.
87
— Load Index, a numerical code
associated with the maximum load
the tire can carry.
S
— Speed Rating 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)
15 x 5-1/2 JJ
15
— Rim diameter in inches.
5-1/2
— Rim width in inches.
JJ
— Rim contour designation.
Tire Speed Ratings
The chart below shows many of the
different speed ratings currently
being used for passenger car tires.
The speed rating 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