Towing Basics

Tow Rating: The manufacturer's recommended towing capacity often based, for larger trucks, on the GVWR plus 2,000 pounds, engine size and axle ratio.


GTWR (Gross Trailer Weight Rating): This figure is located on a metal tag on the trailer frame and is based on the allowable weight of the trailer and its cargo.


GCWR (Gross Combined Weight Rating): Total weight of the tow vehicle and everything in it, as well as the trailer and its contents. If the truck weighs out at 7,000 pounds and has a GCWR of 10,000 pounds, the trailer and its contents cannot exceed 3,000 pounds.


Once you have made sense of these terms as they apply to your situation, you're in a good position to determine if a vehicle is safe to tow the intended trailer and its contents. One rule of thumb: it's far better to have too much tow vehicle in terms of weight and towing capacities than too little. The maneuver that has saved many a road trip is to power the trailer out of trouble—whether it's a heavy crosswind or a fishtailing trailer coming down a grade at highway speeds. The ability of the tow vehicle to regain control, to actually continue to tow instead of being pushed, is vital to everyone's safety. A good example is a two-horse trailer pulled by a 1/2-ton pick-up. Technically, the 1/2-ton is adequate and many recreational, short-distance horse-towers trailer successfully with this set-up. But those who have spent many long hours transporting livestock wouldn't be caught dead in a 1/2-ton. Experience has taught these veterans that a 3/4-ton is the safest tow vehicle for a horse trailer.


One last number, and maybe the most important: Tongue Weight. This term refers to the trailer weight at the coupler that is supported by the truck. The recommended tongue weight is between eight and 15 percent of the total trailer weight. To determine tongue weight, go to a public scale; drive across the scales stopping with the trailer on the scales and the tow vehicle's rear tires just off the scale deck. Record the weight. Jack up the trailer and unhook it from the hitch and record that weight. The difference between the two weights is your tongue weight. Determining the tongue weight is worth this effort. Too much tongue weight and both the tow vehicle and trailer will sway. Too little tongue weight causes serious trailer sway.