GM Service Manual Online
For 1990-2009 cars only

Most P-metric tires do not have exactly corresponding alpha/numeric tire sizes. A P205/75R15 is not equal in size and load carrying capacity to an FR78-15. Because of this, replacement tires should be of the same TPC specification number (size, load range, and construction) as those originally on the vehicle. If you must replace P-metric tires with other sizes, consult a tire dealer. Tire companies can best recommend the closest match.

Identify radial-ply by the letter R or Radial on the sidewall. Encoded on the side wall are the tire type, the tire size, and the aspect ratio (eg. P205/75R15).


Object Number: 156797  Size: SH

The following are the code designations:

    • P is passenger car (LT is light trucks)
    • 205 is the section width (1) of the tire
    • R is the radial type design construction
    • 75 is the aspect ratio (2) (height to width ratio)
    • 15 is the rim diameter in inches

An all-season tire has either M+S, M&S, or M-S imprinted on the sidewall.