How to Calculate 5th Wheel Hitches

Fifth wheel hitches let you tow semi-trailers.

The trailer hitch, otherwise known as a tow bar, joins the chassis of your vehicle to a trailer. The coupling attachment called the fifth wheel is shaped like a horseshoe and attaches to the vehicle. The other part of the hitch, the coupling pin, attaches to the trailer. The hitches come in a range of sizes, so you must choose one strong enough to bear a significant portion of your trailer's load.

Instructions

1. Consult your trailer's owner's manual to find its weight.

2. Add the trailer's weight to the maximum load you will carry. This calculates its gross vehicle weight rating (GVWR). If, for instance, the trailer weighs 15,000 pounds and you plan to carry loads of up to 35,000 pounds, add 15,000 to 35,000, which equals 50,000 pounds.

3. Multiply the gross vehicle weight rating by 0.25, which is the approximate portion of the weight that the hitch must bear. (For example, 50,000 x 0.25 = 12,500 pounds). Select a fifth wheel hitch that carries at least 12,500 pounds.

References

• "Popular Science"; Now: A Wagon/Pickup Fifth Wheel Hauler; Jim Dunne; April 1973
• Sherline: Trailer Loading and Towing Guide

Resources

• Online Towing Guide: Fifth Wheel Hitches