7 Questions Everyone Has About Trailer Tires

Typically, whatever experience or knowledge we have concerning tires comes from dealing with our vehicles. This is a great place to start, but it's also where some of the confusion about trailer tires comes in. Are trailer tires the same as passenger vehicle tires? Do they need to be balanced? How long do they last?

Whether you're replacing a blown out tire, upgrading to a larger one, or simply learning as much as you can about trailer tires in preparation, we've got you covered.

Below, we'll answer some of the most common questions we receive about trailer tires, including:

Do Trailer Tires Need to be Balanced for Proper Performance?
What is Load Range on a Trailer Tire?
Can I Use Trailer Tires on My Car/Truck (Or Vice Versa?)
How Long Do Trailer Tires Last?
Why Do My Trailer Tires Keep Blowing Out?
Why Are Trailer Tires Bias Ply?
How Can You Protect Trailer Tires from Dry Rot?

Watch Now: Best Tire and Wheel Options

Do Trailer Tires Need to be Balanced for Proper Performance?

The short and sweet answer: No.

The "DIY guy" answer: You can have your trailer tires balanced if you wish, but this isn't required. When cruising the highway in your passenger vehicle, you're more likely to feel the vibrations from unbalanced vehicle tires, so vehicle tires are dynamically balanced using a machine and weights.

Trailer tires are different in that their main responsibility is supporting a load behind a tow vehicle, not providing a smooth ride for passengers.

Pro Tip: If you buy new tires for your rims, you can choose to have them balanced if you prefer. Remember that many trailer wheels are centered by the position of the lug bolts (these wheels are lug-centric) and not the center bore of the wheel. For best results, have them balanced using a pin plate adapter. This mimics the way a lug-centric wheel is mounted to a hub.

Pictured: a load range E trailer tire

What is Load Range on a Trailer Tire?

The short and sweet answer: Load range basically tells you the load capacity of the trailer tire.

The "DIY guy" answer: The tire's load range is rated with a single letter, such as B, C, D, etc. If you have a load range D and B tire of the same size, the D tire will have a higher weight capacity.

Keep in mind that load range varies between tire sizes. That is, a size 175/80-13, load range B tire might have a 1,100-lb capacity, whereas a size 205/75-14, load range B tire may have a capacity of 1,430 lbs.

For help determining your potential load ranges based on tire size, check out our chart here.

So which tire load range should you use? In most cases, you should select tires with a load capacity that matches the load capacity of the tires that came with the trailer. If you wish to select tires with a higher load capacity, keep in mind that other components of the trailer also have a weight limit, including the wheels. This means that upgrading to higher capacity tires won't necessarily increase your trailer's load capacity—you'll always be limited by the lowest rated component in your setup. Plus, higher capacity tires usually cost more.

Pictured: ST tire (top) and LT tire (bottom)

Can I Use Trailer Tires on My Car/Truck (Or Vice Versa?)

The short and sweet answer: No (with the exception of LT tires).

The "DIY guy" answer: ST (Special Trailer) tires are made for a specific purpose—supporting the vertical load and cornering forces of trailers. P (Passenger) tires are designed with more flexible sidewalls and are made with passenger comfort and steering in mind. Generally speaking, it's a bad idea to swap them. They simply weren't made to perform in the same way.

There are a few exceptions. LT (Light Truck) tires are sometimes used on larger trailers and fifth wheels due to their stiff sidewalls. LT tires are typically readily available locally, and at affordable prices. They also generally have higher speed ratings than ST tires. If you decide to go with LT tires, make sure they're within your load carrying capacity.

Typically, though, you'll want to stick with ST trailer tires for your trailer. That's what they're made for!

This tire was manufactured in the 17th week of 2018

How Long Do Trailer Tires Last?

The short and sweet answer: 3-6 years.

The "DIY guy" answer: In general, you want to replace your tires about every 3-6 years, but it depends on the tire. In most cases, tread wear isn't the problem for trailer tires. Rather, the biggest problem trailer tires face is that they spend most of their time doing nothing. They are typically parked in one spot between tow jobs, soaking up harmful UV rays, gaining flat spots, dry rotting, and otherwise deteriorating due to oxidation.

Even when stored in a controlled garage environment, tires are still subject to dry rot and flat spotting. And even when they look fine from the outside, it's usually a good idea to replace tires once they're about 5-6 years old at most, or you've run them for about 10,000-12,000 miles.

How Old Are My Trailer Tires?

There's an easy way to tell how old your trialer tires are: it's written right on your sidewall. The DOT (Department of Transportation) ID number code is stamped on one side of the tire. The code begins with the letters "DOT" and is followed by numbers or letters identifying the manufacturing location. The last four numbers of the code represent the week and year the tire was built. For example, the number 0418 means the fourth week of 2018.

Tire Overinflation and Underinflation Wear

Overinflation and underinflation produce distinct tire wear patterns

Why Do My Trailer Tires Keep Blowing Out?

The short and sweet answer: You're probably doing something wrong. (Don't worry, it happens.)

The "DIY guy" answer: There are a lot of reasons tires fail. Here are some of the most common:

Excessive heat caused by underinflating
Overloading the tire
Surpassing the speed rating (listed on the tire sidewall)
Flat spots or sidewall rubbing (which could indicate clearance or braking problems)
Bent spindles (less likely but still a possibility)

Aside from checking the psi with a tire gauge or tire pressure monitor system, an easy way to tell if you're underinflating a tire is to look at its wear pattern. If you notice uneven wear on the outer edges of the tire, it's probably underinflated. In the same vein, if you notice uneven wear down the center of the tire, it's most likely overinflated. When properly inflated and adjusted, your tires should wear evenly.

Pictured: bias tire (left) and radial tire (right)

Why Are Trailer Tires Bias Ply?

The short and sweet answer: They're not. At least, not all of them.

The "DIY guy" answer: There are two type of trailer tires: bias and radial. The main difference between them is how they are constructed. The cords inside a bias ply tire run at a 32 degree angle to the direction of travel, whereas cords on a radial tire run at a 90 degree angle, or across the tire from wheel lip to wheel lip.

So what does this mean for tire performance? Radial tires flex more, which provides better ground contact, traction, stability, and tread wear. A radial tire will normally run cooler than a bias ply tire, and since cooler tires last longer, radials generally outlast bias ply tires. At one time, radials were more costly than their bias ply counterparts, but that's changed, and the two types are now similar in price. Radial tires are great for highway use, making them the more popular choice for modern trailers and campers.

So why would you ever buy a bias tire for your trailer? Bias ply tires have stiffer sidewalls, which is great for applications like agricultural use, where you won't be spending most of your time on the highway.

Whichever tire type you choose, just keep in mind that they are not meant to be mixed. Mixing the two types on the same trailer can cause uneven wear and tracking problems.

Covering your tires helps protect them from the elements

How Can You Protect Trailer Tires from Dry Rot?

The short and sweet answer: Work 'em, then wrap em'.

The "DIY guy" answer: There are some measures you can take to keep your trailer tires healthy and strong. Dry rot is caused by excessive heat and sun, lack of use, and low inflation. Use a wheel cover when your trailer is not in use to guard against UV rays, water, and dirt. Jack up your tires or park on plywood boards when possible to keep your tires off the ground when you're not using the trailer. Make sure they are properly inflated (use a tire gauge or tire pressure monitor system to check—trailer tires can look fine and still be underinflated). For long-term storage, remove your tires and store them in a cool, dark area.

How to Measure the Bolt Pattern of a Trailer Wheel

Measuring a Trailer Tire

How to Determine Tire/Wheel Diameter

Written by: Amber S.

Updated on: 9/3/19

Questions and Comments about this Article

Brian W. 2/23/2020

Great info. I just purchased my first pop up camper for the family. Its an older camper 1995 Jayco Eagle 12. The previous owner did not know how old the tires are. They look fine, but I want to replace them anyway. They are Super Trail 20.5x8.0-10. Since we will be traveling 2 - 3 hrs by interstate to get to the places we want to go, I assume I am going to want radial tires instead of bias ply. What would the radial version of my tire be? size conversion. Thanks

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Reply from Chris R. 2/25/2020

The modern size equivalent to the 20.5x8.0-10 tires on your camper is 205/65-10, however there isn't a radial ply unit available in this size. You'd need to bump up to 12" tires and wheels until you're able to upgrade to radial tires. If you have some room under the fender you could go with the Kenda ST145/R12 # AM10140 or the tire/wheel combo # AM31215 , which would be about 0.6" larger in diameter/height. I do recommend going to radial for better highway driving if this conversion is possible, but if it's not due to fender clearance or bolt pattern, continuing with 205/65-10 bias units like # AM1HP56 would work just fine. 57208

Helpful Links

Tires-and-Wheels/Kenda/AM10140.html

Tires-and-Wheels/Kenda/AM1HP56.html

Tires-and-Wheels/Kenda/AM31215.html

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