* Grade: Pulling uphill requires significantly more force than pulling on level ground. A steep grade dramatically reduces the amount of weight that can be moved.
* Friction: Friction in the wheels, bearings, and between the trailer and the road all reduce the effective pull.
* Rolling Resistance: The type of tires, road surface, and even inflation pressure affect rolling resistance, impacting how much weight can be moved.
* Aerodynamics: At higher speeds, aerodynamic drag becomes a significant factor, especially with a large or less aerodynamic trailer.
* Trailer Brakes: The trailer's braking system needs to be able to adequately control the weight being pulled. If the brakes are insufficient, the vehicle might not be able to stop safely.
* Vehicle's Own Weight and Power: The vehicle's engine power and its own weight affect its ability to accelerate and maintain momentum while towing.
Therefore, there's no single answer to your question. A vehicle with a 20,000-pound drawbar pull might be able to move a significantly larger weight on level ground at low speed than it could on a steep incline at high speed. The manufacturer's specifications for towing capacity (usually given in pounds or kilograms) should be consulted to determine the safe maximum towing weight for that specific vehicle. That capacity takes these other factors into account.
