My layman’s understanding is that the limiting factors for towing capacity are usually the brakes, engine work capacity, and the transmissions ability to handle the prolonged torque without overheating. Are there other factors I’m not considering? Perhaps vehicle weight?
I’ve noticed that rated towing capacities on cars can vary significantly from one year to the next or between models. I’m assuming the reason is that manufacturers are avoiding liability.
For example the 2006 Subaru Legacy has a 2700 lbs towing capacity, while the 2006 Subaru Impreza with the same engine and transmission is 2000 lbs, and the 2006 WRX which is basically an Impreza with a more powerful engine and brakes has a 0 lbs rated capacity.