Over the years, cars have continued to get faster and faster. 70 years ago, the idea that highways would have reached 65 or 70 mph speed limits was outright insane.
Most standard road vehicles at the time couldn’t reach such high speeds, and maintaining those speeds for a long period was dangerous. Over the years, vehicles became safer and faster.
Your tires keep you planted to the road. When a tire fails, the situation can become time-consuming and dangerous.
But how do you rate or compare a tire?
One way to simplify the complexity of tires is through Uniform Tire Quality Grading (UTQG).
Without knowing how to read the UTQG, you would see a series of numbers and letters with no real meaning. This is everything you need to know about UTQG and how to read it.
Tires have become a part of our day-to-day lives and a purchase that needs to happen. Still, most customers don’t know how complex a tire truly is.
It’s like rocket science.
Before making a tire, manufacturers make a plan. First, they discover the purpose of the tire. Will it be for a daily driven car or a minivan? Is this for SUVs and light trucks that could see offroad use? What if the user drives a sportscar or a performance build?
Once the plan is set, they calculate a blend of rubbers to find the right grip, longevity, and feel. Some tires are made of layers like an onion, allowing soft rubber areas to mingle with hard rubber. This creates a feel and longevity that isn’t possible with a single layer.
To make matters more difficult, how the materials are layered also makes a difference.
Finally, tread depth, shape, and angle change how and when you have grip. Tires designed for aggressive cornering will have completely different tread than tires designed for commuting in the rain and snow.
The sidewalls on a tire can be soft or stiff, which also changes everything.
With so many aspects involved in making a tire, how are consumers supposed to understand what they are buying? You can read that a tire has a 60% synthetic blend composite with reinforced sidewalls and 5 tread patterns cut at 20 degrees.
But what will that do for you?
How will that react to your car?
The Uniform Tire Quality Grading creates a standard that can easily give customers a way to compare tires and get exactly what they want.
The UTQG will show three main ratings: treadwear, traction, and temperature.
This will commonly be displayed as a number followed by two or three letters.
An example UTQG would look like this:
140 A A
This information is sometimes printed on the sidewall of the tire as the UTQG number or written out as:
Treadwear 140 Traction A Temperature A
The UTQG was created in 1978 by the National Highway Traffic Safety Administration (NHTSA) to create a standard that all tire manufacturers would have to meet and a method for consumers to compare tires. The NHTSA is a department of the United States Department of Transportation (DOT).
The DOT clearly states that any tire intended to be used on the streets within the U.S. must adhere to their standard guidelines and must be certified.
DOT and NHTSA certifications should not be confused with the International Organization of Standards’ tire identification codes, which show the tire’s composite, dimensions, load ratings, and speed ratings.
Remember, the DOT does not conduct these tests. Instead, they place guidelines on how to complete the tests and give the grades.
While it’s important to verify that passenger car tires have a proper UTQG, some tires may not require a rating.
Snow tires, often referred to as winter tires, are built for snow seasons. These tires are not used in the same way as a standard passenger car and may not have a UTQG.
Most specialty tires do not require a UTQG, including:
Medium to large trucks
Non-road use equipment
To determine the ratings for a tire, the manufacturer must take their tire to San Angelo, Texas to the NHTSA testing facility. There, they must purchase a test tire known as a Course Monitoring Tire (CMT).
The monitor's tire and the company's tire will then be mounted on similar vehicles and driven in convoy. This ensures both tires experience the same conditions and are driven similarly.
The convoy usually includes 4 vehicles and will drive 7,200 miles throughout West Texas public roadways, with periodic stops to inspect the tires.
At the end of the test, the company will take measurements and compare their tire to the CMT.
Treadwear cannot be directly compared to mileage or other forms of measurement strictly due to the conditions. This explains the importance of the CMT.
Road conditions, driving style, temperature, weather, and even the road itself will affect how worn a tire becomes and at what rate.
Treadwear is rated on a scale of 100, with the CMT being 100. A tire can rate higher or lower depending on how it compares to the CMT.
This means that a tire rated at 140 would have far less wear than the CMT, and a tire rated at 50 would have much more wear than the CMT.
Because tires have improved so quickly, this scale does not always relate 1 to 1. A tire rated at 200 does not necessarily wear at half the rate of the CMT.
During these tests, traction is measured as a means of stopping on different surfaces, including asphalt and concrete.
These ratings measure G-force that the tire can withstand, including:
Rating Asphalt Concrete
AA 0.45 +0.39
A 0.47 +0.35
B 0.38 +0.26
C 0.38 or less0.26
These forces are measured in “locked wheel” when the brakes are suddenly applied to put the vehicle in a skid. These tests are conducted at precisely 40 mph.
Temperature ratings focus on the tire’s ability to dissipate heat while driving. If a tire is unable to dissipate heat, long drives on the highway will create dangerous situations.
These ratings are broken down into A, B, and C grades, similar to traction ratings.
“A” refers to tires that accurately dissipate heat at speeds exceeding 115 mph, B-rated tires accurately dissipate heat at temperatures between 100 and 115 mph, and C-rated tires dissipate heat between 85 and 100 mph.
All tires manufactured in the US must exceed a heat dissipation rating of 85 mph or more due to highway speeds. This is intended to ensure a customer won’t accidentally buy a tire that could put them in danger.
Remember that the United States Department of Transportation does not conduct these tests. Instead, the manufacturer is expected to complete these tests and give honest ratings.
The DOT does have the right to review test results.
This puts into question whether a company would skew or slightly change results to meet a specific goal. This isn’t a prevalent issue, but it is possible.
As a consumer, you have access to the UTQG, allowing you to stay well informed as you shop for tires. These ratings are designed as comparison tools, so you can say X tire is rated better or worse than Y tire at a glance.
You should always purchase tires through a reputable dealer. Fake tires do make their way onto the market and are sold at less-than-ideal shops.
Shopping online will help you choose a trustworthy dealer with the ability to price match and find exactly what you want. Rent A Wheel takes this process one step further, allowing you to shop online. Our wheels and tires are shipped to you or a trusted shop free of charge, where they can be mounted and balance for free.
Once your tires are mounted, it’s important to stay in touch with your local shop. They will be your best source for tire rotations and maintenance.
With the knowledge of UTQG, you can now make informed shopping decisions.