We all love to spend time on the water, but it’s safe to say that no one enjoys being stranded on the side of the road with a flat trailer tire. Just as we maintain our boats, it’s important that we maintain our boat trailer tires too. 

When to Buy Boat Trailer tires

DOT date code on the side of a boat trailer tire

Unless you’ve purchased a brand new boat and trailer from a dealer, you are likely to need new tires in short order. If you’re not sure how old your boat trailer tires are, you can check the DOT code that is on the side of your boat trailer tires.

The tire DOT code tells you the week and year the tires were manufactured. In the example above, this tire was made in the 35th week of 2007.

Now that you know the age of your boat trailer tires, you need to assess the tire condition. A quick way to see if you need new tires is by checking the depth of the tire tread. To do this, use the Lincoln penny trick. 

Using a penny to check the tread of a trailer tire

Set the penny, with Lincoln’s head facing down, into the treads of the tires. It’s best to choose different locations on the tire. When you see the top of Lincoln’s head with the coin in position, then it’s time to start looking for new boat trailer tires.

Another thing to check is the sidewalls of the tires. Boat trailers tend to go unused for long periods, especially in the winter. Although the tire tread isn’t wearing out when the trailer is parked, UV rays and freezing temperatures degrade the tire rubber.

Cracks in the sidewall of the trailer tire should be inspected by tire expert.

Cracks from the tires drying out commonly appear in the bead area of the boat trailer tire close to the rim, but sometimes you’ll see small cracks between the tread blocks or in the threads of the tires. 

Shallow cracks and some discoloration is common and is mostly no cause for concern, but deeper cracks demand closer inspection by a tire technician.

What Type of Tire Should You Buy

Tires designed specifically for trailering are marked as ST. You can find the ST mark on the sidewalls of the tire. You may also see something like “Trailer Use Only”. ST-marked trailer tires have reinforced sidewalls to carry heavier loads like boat towing.

There are two kinds of ST tires — bias-ply and radial. The right tires for you depend on the type of tires that originally came on your trailer, how you use your trailer and your budget.

Bias-ply trailer tires tend to be less expensive, and are best for infrequent short hauls, off-road use, and heavier loads. Radial trailer tires are recommended for highway driving because they build up less tire heat when driving long distances. Do not replace bias-ply tires with radial tires without consulting the trailer manufacturer or a professional tire technician.

Load Range

Now that you know what type of tire to buy, it’s time to consider the size and the load capacity. 

Load range on trailers is classified by the letters B, C, D, or E. The letter B is the lightest classification and E is the heaviest. Most boat trailer tires are classified as C or D. 

If boat trailer tires hold a C Load that means it can carry up to 1,820 lbs. On a single axle trailer, this means that the boat trailer tires can support up to 3,640 lbs. This includes the weight of the trailer, the boat, the boat’s engine, as well as anything else on the boat. 

Keep in mind that single axle trailers can carry 100-percent of their load rating, but double axle trailer loads must be reduced by 12-percent.

Proper Use and Maintenance 

While we want to get to our boating destination as quickly as possible, boat trailer tires are designed for towing speeds not to exceed 65 mph.

Exceeding that maximum towing speed for long periods can lead to tire failure. If you are going to be traveling at highway speeds, you don’t want the weight of the load maxed.

Avoid loading up the boat with extra weight during transport. It’s a good idea to move heavy cargo from the boat to the back of the vehicle itself, which should allow your trailer tires to withstand slightly higher speeds for longer periods of time.

During the winter season when the trailer is not in use, itis important to protect the tires from UV rays. A standard tarp or coverage in a garage will do the trick.

Also, you need to rotate and balance your boat trailer tires just as you do for your car. Rotating your tires from side to side on a single axel trailer will help even out irregular treadwear and extend the life of the tire. On a double axle, the standard X-pattern rotation is in order from time to time.