Generally speaking, trailer hitches are classified either weight carrying or weight distributing. The type best for you depends entirely upon the tow vehicle and trailer size and weight.

The weight carrying type of hitch is used in applications where trailer weight is up to and including a maximum of 3,500 lbs and where the weight and suspension of the tow vehicle can accommodate that load. Weight distributing hitches are normally used for heavier trailers, up to 10,000 lbs. They are also used when the weight and suspension of the tow vehicle in relation to the trailer weight requires redistribution of hitch weight. They can also be used as a weight carrying hitch with up to 5,000 lbs gross trailer weight.

With a weight carrying hitch, all trailer tongue weight, plus approximately 50% additional weight, must be carried by the tow vehicle’s rear axle and tires. With heavier trailers, this causes the vehicle to lower itself over the rear axle, causing a weight shift from the front wheels. This weight reduction causes the front wheel camber to change and affects steering performance. Overload springs or air shocks added to the rear of the tow vehicle won’t help the situation.

Although springs raise and level the vehicle, the entire vehicle now rides higher over the chassis; therefore, steering and handling characteristics may be affected. Furthermore, because front-end weight is now transferred toward the rear, it adds to the tow vehicle rear axle load. Calculations have proven this additional weight to be about 50% of the original tongue weight. For example, a 400 lb original tongue weight is in effect increased to 600 lbs additional rear axle load. The front-end load is reduced by 200 lbs. This extra load increases tire wear appreciably and may contribute to handling problems. For these reasons, it’s important that the tow vehicle not be overloaded to the point of causing safety problems.

Beginning in the 1950s, trailers grew larger and heavier. In order to overcome the inherent problems of weight shift encountered in towing these heavier units, the weight distributing hitch was developed. Today, we have “down-sized” tow vehicles and trailers that also require redistribution of hitch weight. The principles used originally to develop weight distributing hitches continue to be applied today, with little change.

To help explain how a weight distributing hitch works, let’s imagine a pair of wheelbarrow handles rigidly attached to the rear of a car in such a way that they parallel the car’s very movement. With the car unloaded, the wheelbarrow handles are parallel to the ground and level with the car. Now put a 400 lb weight in the trunk. The rear of the car will drop a few inches, causing the wheelbarrow handles to point at the ground and the front of the car to raise several inches. Now if one were strong enough, they could lift up the wheelbarrow handles and bring the car back to the level position. In doing so, they transfer weight from the rear wheels back to the front wheels and their feet.

If they continued to lift until the rear wheels were off the ground, then all the weight would be distributed between the front wheels and their feet. If a weight distributing hitch is substituted, spring bars on the hitch become the “wheelbarrow” handles. The spring bars attached to the ball mount have no vertical movement, but they are free to swing side to side as the car and trailer turn corners. Chains and snap-up brackets attached to the spring bars become the lifting force when positioned and tensioned from the trailer frame. Since the spring bars are pulled up by the chains attached to the trailer frame, tongue weight is distributed to the tow vehicle’s front and rear wheels. Also, because the spring bars are simultaneously pulling down on the trailer frame, a portion of the hitch weight is transferred to the trailer wheels.