Contact Us Newsletter
Searching for tire
Your configuration
What is the of your vehicle?

You're about to start a new search

All the items will be deleted.

Dealer Locator
Contact Us Newsletter

READING A TIRE SIDEWALL

A tire’s sidewall is pretty much what it sounds like – the outer and inner “walls” on the sides of a tire, if facing a tire on its side. Every sidewall has its own unique information that is divided into four main sections:
    • -  Updated on 

1. TIRE SPECS

This describes the fundamental characteristics of your tire. Size, construction, speed rating and more.

Tire type

This designates the type of vehicle the tire fits. P is for passenger metric. Other letters are LT (for light truck), T (for temporary spare) and ST (for special trailers). If your tire has no letter, it signifies that your tire is a euro “metric” size.

Tire Width

Also called Section Width, this is the width of the tire (or thickness) in millimeters, if measured from a tire’s widest point of its outer sidewall to the widest point of its inner sidewall. Why millimeters? It originated in Europe, which uses the metric system.

Ratio

This identifies the tire’s aspect ratio, which is the relationship of the tire’s sidewall height to the tire’s width. In this example, the sidewall height of the tire is 55% of its width. The lower the ratio, the smaller the sidewall height, which means better cornering, but a rougher ride.

Construction

This is the tire’s internal construction, which is “radial.” Almost every tire on the road has radial construction, which means the cords of the carcass plies inside the tire “radiate” directly across from one side of the tire to the other. Other letters used are D, for diagonal construction, and B, for belted.

Wheel Diameter

This number (in inches) indicates that the tire is designed to fit on a wheel with a 18-inch diameter.

Load Index

This indicates how much weight the tire is certified to carry at maximum safe inflation. It doesn’t mean 97 pounds, because it’s actually an assigned value that corresponds with its “actual” load capacity found on a load index chart. If you look up 97 on the chart, you’ll find 1,609 pounds. (To see the load index chart on the Tire Speed Ratings & Tread Life page,

Speed Rating

This indicates the maximum safe speed at which a tire is certified to carry a load under specified conditions. Speed ratings range from A (lowest) to Y (highest), with one exception: H falls between U and V. To find the maximum speed for your tire, refer to the speed rating chart*. Exceeding the lawful speed limit is neither recommended nor endorsed.

2. DEPARTMENT OF TRANSPORTATION SAFETY CODE

This assures that your tire complies with all Department of Transportation (DOT) safety standards. After the DOT insignia is your tire’s identification number, which begins with the tire’s manufacturer and plant code where the tire was manufactured (two numbers or letters). The ninth and tenth characters tell the week the tire was manufactured. The final number(s) signifies the year the tire was manufactured.

  • DOT

    Department of Transportation Safety Code

  • B9

    Tire's manufacturer and plant code

  • YR

    Denotes tire size.

  • UJNX

    Optional characters that identify brand and other significant characteristics of the tire

  • 50

    Denotes week the tire was produced

  • 08

    Denotes year the tire was manufactured.

3. UTQG CODE

The Uniform Tire Quality Grading (UTQG) was established by the National Highway Traffic Safety Administration (NHTSA) to test tires following government prescribed test methods and then grade each tire on three main components:

  • Treadwear: This is the wear rate of the tire, comparable only to other tires within a tire manufacturer’s line. 100 is the baseline grade. Therefore a tire with 200 would theoretically last twice as long on the government’s course compared to a tire with 100.

  • Traction: Traction grades are AA, A, B and C (with AA being the highest grade). They represent the tire’s ability to stop straight on wet pavement as measure on a specified government track. Any tire rated under C is considered unacceptable for road travel.

  • Temperature: The temperature grades, from highest to lowest, are A, B and C. These represent the tire’s ability to dissipate heat under controlled indoor test conditions. Any tire rated below C is considered unacceptable.

4. ICONS

Some tires have unique benefits, as showcased with specific icons. For example, a Mountain Snowflake symbol tells you that the tire meets or exceeds industry-established snow traction performance requirements.

Frequently asked questions

BFGoodrich answers your most asked questions.

FAQ

Find the DOT code on the sidewall and look at the four digits at the end. The first two are the week of manufacture, the last two are the year. A code ending 3624 means the 36th week of 2024. Check this on any tire that has sat in storage and on every used vehicle purchase, because a tire can be years old before it is ever mounted.

It certifies the tire complies with Department of Transportation safety standards and identifies where and when it was built. The opening characters identify the manufacturing plant, the middle group is a manufacturer size and type code, and the final four digits are the date. Tires sold in Canada and the United States carry the full serial on one sidewall and a partial on the other.

It designates vehicle type. P is passenger metric, LT is light truck, T is temporary spare, ST is special trailer. No letter signifies a Euro metric size. LT tires have stiffer construction and higher load capacity for towing and heavy payloads, so fitting a P-metric tire where LT is specified leaves you short on load capacity.

The aspect ratio is sidewall height as a percentage of section width. A 265/70 tire has a sidewall 70 percent as tall as it is wide. The lower the ratio, the shorter the sidewall, which means sharper cornering but a rougher ride. On Canadian roads with frost heave and potholes, a taller sidewall absorbs more of that punishment.

The load index is an assigned value, not a weight. A load index of 97 corresponds to roughly 730 kg per tire on the standard chart. It represents how much weight the tire can carry at maximum safe inflation. Your replacement tire's load index must meet or exceed what your vehicle placard specifies.

No. The sidewall figure is the maximum the tire can safely contain, not the recommended operating pressure for your vehicle. Use the door jamb placard. Running at the sidewall maximum overinflates most vehicles, shrinks the contact patch, reduces grip, and wears out the centre of the tread early.

Related pages