GMC Terrain Quiz
Vehicle Care

Tire Designations

In this manual: Vehicle Care
Introduction — 1In Brief — 46Keys, Doors and Windows — 37Seats and Restraints — 60Storage — 6Instruments and Controls — 58Lighting — 16Infotainment System — 1Climate Control — 8Driving and Operation — 128Vehicle Care — 75Service and Maintenance — 8Technical Data — 5Customer Information — 18OnStar — 6Connected Services — 4
6steps
~36min
2/5difficulty
Done 0 of 6

Tire Size

The following is an example of a typical passenger car tire size.

GMC Terrain. Tire Designations
  1. Passenger (P-Metric) Tire: The American version of the metric tire sizing system. The letter P as the first character in the tire size means the tire is a passenger car tire designed to standards set by the U.S. Tire and Rim Association.
  2. Tire Width: The three-digit number indicates the tire section width in millimeters from sidewall to sidewall.
  3. Aspect Ratio: The two-digit number indicating the ratio of the tire's height to its width. For example, if the tire size aspect ratio is 60, as shown in item 3 of the illustration, this would mean the tire sidewall height is 60 percent of its width.
  4. Construction Code: The letter code used to indicate the type of ply construction in the tire. The letter R means radial ply construction; the letter D means diagonal or bias ply construction; and the letter B means belted bias ply construction.
  5. Rim Diameter: The diameter of the wheel in inches.
  6. Service Description: These symbols represent the load index and speed rating of the tire. The load index represents the load carrying capacity the tire is certified to carry. The speed rating is the maximum speed a tire is certified to carry a load.

Test yourself

A quick GMC Terrain quiz: every answer comes with an explanation and a link to the manual page.