Parts of a Tire

Tires are a driver’s only contact with the road, transferring actions such as steering, braking, accelerating, and turning. They are specifically chosen for each vehicle, making tires one of the most important safety features on a car, truck, or crossover. See your Certified Service experts for tips and helpful advice so you can make an informed decision on the right tires for you.



Tires are made up of many different parts, and it’s important to understand how they work.

A. Belts
Rubber-coated layers of steel, fiberglass, rayon, and other materials located between the tread and plies, crisscrossing at angles, hold the plies in place. Belts provide resistance to punctures and help treads stay flat and in contact with the road.

B. Sipes 
Sipes are special treads within the tread that improve traction on wet, dirty, sandy, or snowy road surfaces.

C. Tread 
The portion of the tire that comes in contact with the road.

D. Grooves 
The spaces between two adjacent tread ribs are also called tread grooves. These allow water to escape effectively.

E. Shoulder 
The outer edge of the tread that wraps into the sidewall area.

F. Sidewall 
The sidewall of the tire protects cord plies and features tire markings and information such as tire size and type.

G. Inner Liner 
This is the innermost layer of a tubeless tire that prevents air from penetrating the tire.


Since tires play a major role in establishing the performance and handling characteristics of a vehicle, many manufacturers require their tire suppliers to identify their Original Equipment (OE) tires with symbols or codes branded on the sidewalls.

The goal is to make it easier for owners to identify and select exact replacements when their OE tires wear out. The information provided below will allow you to decode the information on a tire sidewall and help you make the right choice in replacement tires. And your Certified Service experts are always there to answer your questions and provide helpful advice.

A. Tire Size 
The tire size is a combination of letters and numbers used to define a particular tire’s width, height, aspect ratio, construction type, and service description.

B. Maximum Cold Inflation Load Limit 

This information tells the maximum load that can be carried and the maximum pressure needed to support that load. Please note that you should always inflate your tires to the pressure noted on the tire pressure placard (typically located on your driver door frame) or in your Owner’s Manual. To find more information on tire pressure and inflation, click here.

C. Tire Performance Criteria Specification (TPC Spec)
Most OE tires designed to GM’s specific tire performance criteria have a TPC spec code molded onto the sidewall. GM’s TPC specs meet or exceed all federal safety guidelines.
D. Winter Tire Symbol
Tires designed specifically for use in winter conditions (snow, slush, ice, and low temperatures) feature a three-peak mountain snowflake symbol.