What Do the Numbers on the Side of the Tire Mean?

Today's vehicles are more intelligent and safer than ever before. New Chevrolets and GMCs come loaded with world-class safety features designed to give you more confidence while on the road. However, these safety features pale in comparison to the original safety feature - your tires. As the only part of your vehicle that physically touches the road, having safe, operational, and functional tires is non-negotiable. Even so, many overlook their tires and fail to pay them the proper attention they deserve. To help, Woody Folsom Chevrolet GMC has created a guide on reading the numbers on your tires and other maintenance tips. Continue reading for more. 

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What Do the Letters and Numbers on My Tires Mean?

You will notice letters and numbers on the side when you look at your tires that match the tire letter code. 

Tire Letter Code

The tire letter code informs the type of vehicle the tire is designed for:(P) indicates it's a passenger vehicle tire for cars, SUVs, crossovers, minivans, and smaller pickup trucks. Other potential codes include light truck tire (LT) and special trailer (ST).

The Three-Digit Tire Width Number

The following figure will be the tire's width, which measures from side to side in millimeters. Many Chevrolet and GMC trucks have a tire width of 275, while the GMC Acadia may have a tire width of 235. 

The Aspect Ratio

A forward slash separates the tire width from the aspect ratio. The aspect ratio is a two-digit number that informs the tire's sidewall height or profile. The bigger the aspect ratio, the taller the sidewall. For example, a GMC Canyon would typically have a higher aspect ratio than a set of low-profile tires for a Chevrolet Camaro. 

The Construction Type Letter

After the aspect ratio, you should see a single letter that informs you of the internal construction of the tire, such as:
  • Radial ( R ) tires represent the industry standard
  • Diagonal Plies or Bias-Constructed Tires (D) represent an older construction type still used by some trailers and motorcycles. 

Wheel Diameter

Wheel diameter is a two-digit number that represents the distance between the two bead seat areas. 

Load Index

The load index is a two- or three-digit number that indicates the weight the tire can support based on a chart. 

Speed Rating Letter

The final letter on the tire is the speed rating, indicating the highest speed at which you can safely travel for an amount of time. 

How Do I Know If My Tires Are Healthy?

Our Woody Folsom Chevy GMC experts ensure your tires are in peak condition. We check tire pressure using a reliable gauge to confirm they match the manufacturer's recommendations, providing a safer, more efficient ride. Tread depth is assessed to guarantee your tires maintain optimal grip, using simple tests like the penny test to evaluate wear. Finally, the overall condition is inspected for signs of punctures, bulges, or cracks, which could compromise safety. Our technicians are skilled in identifying issues and recommending solutions so you can confidently drive, knowing your tires are road-ready.

Contact Woody Folsom Chevy GMC Today

Ensuring your tires are safe and functioning starts with scheduling an inspection at Woody Folsom Chevy GMC. Contact us today.Â