Understand Trailer Tire Speed Rating: The Detailed Explanation

Vehicle tires are designed to handle different types of loads and speeds. The trailer tire speed rating is the maximum speed a travel trailer tire can travel while carrying a load.

Also, some vehicles may have a speed limit because of their tires’ speed and load index. It’s essential to carefully choose the speed rating on trailer tires when buying new ones, as not all tires are created equal.

What Is the RV Tire Speed Rating?

You may see a letter or number on the sidewall when looking at a tire, which is the speed rating. It indicates the maximum speed at which you can drive the tire safely driven. It is not a recommendation of how fast to drive the vehicle.

The speed rating system was developed in Europe to regulate a tire’s safe performance at certain speeds. In the original rating system, the maximum speed rating was the “Unlimited V” category (over 210 km/h or 130 mph).

The rating scale in the USA is set by the United States Department of Transportation (DOT). The letters and numbers correspond to a speed limit for the tire. For example, if you see “H” on a tire, that means the maximum speed for that tire is 130 mph.

Not all tires are equal. A higher-speed-rated tire will typically cost more than a lower-speed-rated one. It’s essential to match the correct speed rating for your vehicle and driving habits.

Tire Trailer Speed Rating Explanation

The trailer tire speed rating chart follows a letter code system. You will see a letter ranging between A1 and Y on the sidewall of every tire. Each letter indicates a maximum speed limit, so you should not cross that limit while driving the vehicle.

The lowest A1 rating is for up to 3 mph of speed, while the highest Y category tires have a speed limit of 186 mph. Tires rated safe for over 186 mph speed limit will have the symbol (Y) on their sidewall.

All tires rated for over 149 mph must have the symbol “ZR” in their size designation.

How to Determine the Speed Rating

There is a specific testing machine to determine a tire’s speed and heat capacity. The manufacturers perform these tests based on the Economic Commission for Europe or ECE standards.

The test involves spinning an adequately inflated tire for 10 minutes. The starting speed should be 40 km/h slower than the proposed rating level, and it will be gradually increased to the target level. The ideal temperature of the testing environment is 77ΒΊ F.

A tire will pass the speed rating if it does not show any damage after the testing. Some higher-quality tires that meet the Society of Automotive Engineers or SAE standards undergo more rigorous testing.

What Is the Speed Rating of a Trailer?

Most trailer tires have a speed rating of 65 mph or less. However, some high-performance trailer tires can reach speeds up to 75 mph. Select the correct tire for your needs to ensure the safety of you and your passengers.

S (112 mph) and T (118 mph) are the most common ratings for light trucks and minivans. Some light trucks and sports and passenger cars can also have the H rating (130 mph).

However, the most common speed ratings for the tires of light trucks are N (87 mph), P (93 mph), Q (99 mph), and R (106 mph). Tires of high-performance vehicles come with V (149 mph), W (168 mph), and Y (186 mph) ratings.

The speed ratings of most trailer tires are K (68 mph) and L (75 mph). It’s safe not to exceed the speed beyond 65 mph.

Tires also come with a load index, indicating the total weight they can carry safely. Besides maintaining the speed rating, you should also follow the load rating for RV tires.

How to Find Trailer Tire Speed Rating

You can find the speed rating on the tire sidewall. You will see a letter and number combination that carries various information about the tire. There are a handful of letters and numbers from left to the right, indicating class, section width, and other information about the tire. The speed rating (a letter) will be on the right-most side.

If you don’t find the speed rating on the sidewall, look for it in the owner’s manual. You can also find it imprinted on a door sticker on the driver’s side. If nothing helps, go to the tire manufacturer’s website or contact its dealer shop.

Final Words

Always drive your RV according to the trailer tire speed rating. Never exceed the speed rating of the tow vehicle or trailer tires; go according to whichever rating is lower.

When purchasing new trailer tires, read the label on the sidewall to find out the speed rating. If you’re not sure which rating is best for your needs, consult with a professional at your local auto shop.

Scott Wilson
Scott Wilson
Scott Wilson is a seasoned RV traveler and professional mountain biker with a great sense of humor. After earning a Master's degree in Automotive Engineering from Columbia University, Scott spent years working as an RV technician at Camping World and Outdoorsy. Today, he enjoys exploring the US in his fifth wheel and truck with his wife. With over 15 years of RV living and road tripping experience, Scott now shares his knowledge and expertise as a travel blogger, helping others make the most of their RV adventures.

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