Cab and box size, transmission type, wheel drive, axle ratio and engine size are all variables that can affect the RAM 1500 towing capacity. Other items that can impact the towing capacity include the gross vehicle weight, the trailer weight and the trailer tongue weight.
Trucks with a smaller cab and shorter box have a lighter curb weight, which is the total weight of the truck including fuel, fluids and equipment, but excluding the passenger and cargo. A lighter curb weight increases the amount the vehicle can tow.
Manual transmissions allow the driver to select the appropriate gear to match the load being towed. This gives him more control over heavier loads on tough terrain. Typically, the larger the engine, the more power and torque it provides to the drive train and the larger the towing capacity.
The axle ratio of a RAM 1500 also affects the towing capacity, with the lower ratio giving better fuel efficiency and the higher ratio providing more towing power and quicker acceleration. Two-wheel drive trucks typically weigh less than four-wheel drive models, which translates to a slightly higher towing and payload capability.
A large variable is the gross vehicle weight. The manufacturer-listed towing capacity is not calculated to include a full load of passengers as well as a load of cargo in the box. The weight of these items must be removed to calculate the actual available towing capacity.