Factors that affect towing capacity

Factors that affect towing capacity

By Bill Roebuck

A typical sedan can tow a load--say a small boat on a trailer--weighing about 1,000 lb (450 kg), while larger cars and minivans can offer 3,500 lb or so. Light pickup trucks and SUVs may even tow more--even in the 5,000 lb. Heavy duty trucks even more.

What makes the difference?

It isn't just horsepower or torque of the engine, although they certainly are key factors, according to Richard James, a spokesman for General Motors of Canada. Towing capacity also is affected by other inter-related components, such as the configuration of the engine, such as whether it has overhead camshafts versus overhead valves.

Other factors include the axle ratio; transmission configuration (rear- versus front-wheel drive); engine, transmission and oil cooling equipment; frame design; unibody structural integrity -- primarily at the hitch-to-car mounting location; wheel, tire and suspension load ratings; brake size and material; and electrical systems to handle lights and possibly brakes on the trailer.

Manufacturers build in less or greater towing capacity based on the likelihood of the vehicle to be used for towing, based on customer profiles and demographics.