Every tire has a load range, and trailer tires are no different. Marked on the sidewall, the load range runs from the lightest weight the tire can carry (Load Range B) to the heaviest (Load Range E). Load range is a measure of an individual tire's maximum capacity to carry a boat and trailer. Most boat trailer tires have a load range of B, C, or D. If a tire has load range C, it can carry 1,820 pounds. If it's on a single-axle trailer, this means both tires can carry a total of 3,640 pounds, which includes the weight of the trailer, the boat, the engine, fuel, and anything else inside the boat.