Folks,
Matching trailer to tow vehicle is a matter of numbers, not opinion. Manufacturers give tow ratings in pounds for their vehicles in their literature.
Trailer Life magazine gives a compilation of those ratings going back a number of years and makes them available on its website
www.trailerlife.com in their Tech section. With a truck the first thing you should do it get its rating.
We like to discount tow ratings by a 10% safety factor to allow for truck loading beyond the standard driver + fluids, for state of tune, for effects of aging, and general caution. That applies to all engine types and locations. Simply multiply the listed tow rating by 0.9 to get your final rating.
However, normally aspirated internal combustion engines operated in the mountain or Pacific west need a higher, 20% safety factor. Such engines lose 3% of their rated horsepower for each 1,000 feet above sea level. That means that at Flagstaff, AZ or on the South Rim of the Grand Canyon, a truck would have lost 21% of its rated HP. To make matters worse, folks towing in the west routine encounter 6-9% grades 5-10 miles long even on Interstate Highways: Grapevine Pass on I-5, and Cajon Pass on I-15 near LA; Lookout Pass on I-90 in Idaho; Donner Pass on I-80 in the Sierra; and Siskyou Pass on I-5 on the CA-OR border. If you would ever tow in the west with a gasoline engine, multiply the tow rating by 0.8 to get your final rating. Turbo diesels do not take this hit since being supercharged, they only take a 1% hit per thousand feet. Stick with 10% for them.
For the trailer end of the equation, use the manufacturer's gross vehicle weight rating, GVWR. It can be found on every trailer made in the past 15 or so years on the DOT plate affixed on the left sidewall near the front. Unlike the unladen, dry weight, an approximation at best, it is a real number required by the Feds and represents the maximum weight to which the trailer should be loaded. Some mfr literature lists it in terms of unladen weight +
carrying capacity. Just add the two to give you GVWR.
You should never tow a trailer which has a GVWR greater than your truck's properly discounted tow rating.
It is just that simple.
You can kid yourself along that your F-150 can pull that 15,000 lb fiver. Maybe you can on the flat and easy. However, you are compromising operating life, stability and emergency handling. Go back the start of this section and view the two video horror stories there. Each of those two poor souls probably thought he was pulling his load just fine...until the magic moment arrived.
My motto on the matter of tow ratings is that it is like shooting angry, charging grizzly bears -- there is no such thing as overkill, but there sure as hell is such a thing as
underkill. ;D
