Can I Swap 205/75-15 Tires with 235/80-16 Tires on Dual Axle Trailer

Question:

I'm currently running 205/75-15 tires on my dual axle trailer. Can I go up in size to a 235/80-16? At most, the trailer fully loaded would weigh about 8K.

asked by: Bert Q

Expert Reply:

The 235/80-16 tires will be about 3.6 inches in diameter larger than a 205/75-15 tires. Half that difference (1.8 inches) is how much closer the tire would be to the fender. When fully loaded, you will want to see no less than 3 inches of clearance between the top of the tire and the underside of the fender when the trailer is loaded. So, unless you currently have about 4.8 inches of clearance between the top of your existing tire and the underside of the fender, you'd be in danger of bottoming out the tires against the fenders if you went with the larger tire.

If your leaf springs currently ride under your axle, and your axle is either 2-3/8 or 3 inches in diameter, you can use an over-under conversion kit, and gain about the diameter of your axle in height, which will add to your clearance and might make the difference. For a 2-3/8 inch axle, use part # K71-384-00 or # K71-385-00 for a 3 inch axle.

The wheel/tire combo you need would depend on the bolt pattern of your current wheels (see the linked FAQ article to determine your existing bolt pattern). If you have a 6 on 5-1/2 inch bolt pattern, the # TA39VR would work well. Each tire has a capacity of 3520 lbs at 80 psi. If your hubs have an 8 on 6-1/2 inch bolt pattern, use # AM34903 which have a 3500 lb capacity at 90 psi.

Keep in mind that going with a larger tire with a higher weight rating won't necessarily increase the weight bearing capability of your trailer. You'll still be limited by the capacity of the lowest rated component, be it the axle, spindles or suspension.