How Large Of A Tire You Can Put On Your Trailer

Question:

I have some smaller trailer wheels on a very small trailer. Id like to get bigger wheels so i get some better longevity/durability on long road trips with the boat. How can i determine what size I can go up to?

asked by: Webb

Expert Reply:

It depends on a couple of factors. First, you will be more limited if you have a dual axle trailer. If you have a single axle trailer the next limitation would be the wheel well clearance. I would load your trailer down quite a bit to see how low it will sag. You don't want to tear up your tires and wheel wells when you have a lot of weight on the trailer. Once you load the trailer down, check and see how much clearance you have. Mark that down for later. Then, get your current tire size and the lug pattern. Write it down.

Now, get all your measurements in order. Let's say you have a single axle, 5x4-1/2 pattern, 205/75R15 and you think you can get a tire that is 2 inches taller than your original. So you have a tire like this one # AM32397, you could upgrade to a 225/75R15 because it will be a taller tire due to the first number being bigger than your original. We recommend having at least 3 to 4" of clearance between the top of the tire and fender (unloaded).

It is also useful to check out the description and it shows the "outer diameter". So, if you have a tire like this # AM30120 one you were looking at and you have around 2 inches of room to upgrade, you could get the # AM3H440 tire which has an increase of around 2 inches in outer diameter. Note that if you grab a tire that is 2 inches larger in diameter, then you'll gain an inch on both the bottom and the top. For example a tire that is 2" larger than his existing unit will only cut into your fender clearance by 1".

If you could fit a radial tire on your trailer, that is the way to go if you're wanting to get a tire that will have a longer life.

expert reply by: Adam E