Another important part of towing is the trailer hitches. Just in case you don't already know... I'm gonna tell you the few basics of trailer hitches. Trailer hitches are rated according to capacity of the load weight and tongue weight. The tongue hitch weight is the downward force exerted on the hitch ball. It's calculated at 10-15 percent of the maximum rated GTW. The tongue is usually formed from the V-shaped merging of the trailer framerails at the front of the trailer. The coupler of the trailer is what accepts the hitch ball. When you know the weight you'll be towing and that the weight doesn't exceed the maximum towing capacity of your tow vehicle, you're ready to determine the proper hitch. A Class III hitch will tow most campers and car trailers. The Class IV hitch tows much heavier loads about up to 7,500 pounds.