TOWING DEFINITIONS AND TERMS

HITCH ASSEMBLY: Often described as the “hitch”, it is mounted to the low vehicle (most often to the vehicle frame) and includes a hitch receiver, ball mount adaptor, hitch ball and wiring harness.

HITCH RECEIVER: The part of the hitch assembly that permits insertion of the ball mount adapter.

DRAWBAR (BALL MOUNT ADAPTOR): A metal bar that carries the hitch ball and is inserted into the hitch receiver. There are some hitch assemblies available with permanently mounted or fixed ball mount adapter/drawbar.

HITCH BALL: The steel ball bolted through the ball mount adapter or hole in the low vehicle’s rear bumper. The coupler on the trailer goes over the hitch ball.

COUPLER: Affixed to the trailer tongue, the coupler is a hollow metal stamping that cover the hitch ball.

FIFTH-WHEEL HITCH: A special high platform with a coupling that mounts over the rear axle of the tow vehicle. Connect a vehicle and fifth-wheel trailer with a coupling kingpin.

FIFTH-WHEEL TRAILER (ALSO SEE GOOSENECK TRAILER): One of which the King pin of the trailer attaches to a specially designed hitch mounted in the bed of a pickup truck. It is most popular with large travel, moving and horse trailers.

GOOSENECK TRAILER (ALSO SEE FIFTH-WHEEL TRAILER): The gooseneck trailer employs a ball socket hitch which attaches to a ball mounted in the bed of a pickup truck over the rear axle. The hitch mounts to the vehicle frame.

GROSS VEHICLE WEIGHT (GVW): The total weight of the tow vehicle, including driver, passengers, any special equipment (options, accessories and up fitted equipment), cargo, fuel, coolant, trailer tongue weight, etc.

GROSS VEHICLE WEIGHT RATING (GVWR): The maximum allowable total weight of the tow vehicle, including driver, passengers, any special equipment (options, accessories and up fitted equipment), cargo, fuel, coolant, trailer tongue weight, etc.

GROSS TRAILER WEIGHT (GTW): The weight of the trailer plus all the cargo in it. This is measure by putting a fully loaded trailer on a scale.

GROSS TRAILER WEIGHT RATING (GTWR): Maximum allowable weight of the trailer, plus its cargo.

GROSS COMBINATION WEIGHT (GCW): Total weight of a fully equipped truck and trailer with cargo, driver and passengers, fuel coolant, equipment, etc.

GROSS COMBINATION WEIGHT RATING (GCWR): Maximum allowable gross combination weight.

TRAILER TONGUE WEIGHT: The downward force exerted on the hitch ball by the trailer coupler. In most cases, it should not be less than 10 percent of the trailer load or more than 15 percent. (Also see King Pin Weight below)

KING PIN: The main fastening member between a fifth-wheel hitch and a trailer.

KING PIN WEIGHT: The downward force exerted on the king pin and pickup bed by fifth-wheel trailers (25 percent of the GTW)

PAYLOAD: The sum resulting from subtraction of the curb weight from the gross vehicle weight rating (GVWR).

TOWING CLASSES:
There are the five classifications for the trailer weights and hitches:

CLASS 1 - LIGHT DUTY: - 2,000-pound maximum. - Includes folding camping trailers and trailers for small boats, motorcycles and snowmobiles.

CLASS 2 - MEDIUM DUTY: - 3,500-pound maximum. - Single-axle, small to medium length (up to 18 feet) trailers

CLASS 3 - HEAVY DUTY: - 5,000-pound maximum. - Dual-axle or large single-axle trailers - Weight-distributing hitch not required, unless specified for the particular vehicle

CLASS 4 - EXTRA HEAVY DUTY: - 12,000-pound maximum. - Largest travel trailers made for recreation - Weight-distributing hitch is required; as indicated by each weight classification 12,000-POUND AND OVER - Must be a fifth-wheel or gooseneck, or pintle hitch.

NOTES ON GETTING HITCHED
WEIGHT-CARRYING HITCH: A weight-carrying hitch supports the trailer tongue weight, just as if it were luggage located at a hitch ball or some other connected point of the truck. These kinds of hitches are commonly used to tow small and medium sized trailers.
There are three styles of weight-carrying hitches: - Fixed Drawbar: in which the ball platform is permanently welded to the hitch - Removable Drawbar: in which the ball platform is removable. This hitch is commonly referred to as a utility ball mount for Class 3 hookups.

WEIGHT-DISTRIBUTION HITCH: A weight-distributing system includes a receiver attached to the tow vehicle, plus a removable hitch head and spring bar assembly that fits into the receiver opening and hook up brackets that connect the spring bars to the trailer frame. This allows towing of trailers with greater tongue weights - typically Class 4 categories- up to 12,000 pounds.

FIFTH-WHEEL HITCH: A fifth-wheel hitch is a special high platform with a coupling that mounts over the rear axle of the tow vehicle. It Connects a vehicle and fifth-wheel trailer with a coupling kingpin. It is most popular with large travel, moving trailers.

TOWING AND AXLE RATIOS: On rear-wheel-drive vehicles, rear-axle is an important part of a successful towing equation. It is expressed as a ratio between the driveshaft revolutions per minute and the rear axle’s revolutions per minute. It is always given as a numerical shaft expression like 4.1:1. This means the small pinion gear at the end of the drive shaft must rotate 4.1 times for every single rotationof the rear axle /shafts. Each rear-axle ratio in the spectrum of those offered has a plus and minus. A ratio that is “low” in the number of drive shaft rotations for every axle rotation results in lower engine rpm and in better fuel economy, longer engine life and quiter running. But it won’t be good for quick acceleration, climbing grades, carrying loads or pulling a trailer. A “high”ratio, one with a high number of drive shaft turns like the 4.1:1 is better for quick acceleration, climbing grades, carrying loads or pulling a trailer. However, it results in lower fuel economy and is noisier when running at high vehicle speeds. For any application, it is best to determine a rail that will enable your Ram vehicle to pull a trailer with the engine operating closest to its optimal power range - where peak torques and peak horsepower meet on the engine power curve chart. This maximizes power, efficiency fuel economy. It is best to determine a rail that will give good trailer towing power without handicapping non-towing performance too severely.