Towing terminology and guidelines.

I have had several customers lately ask me about the different terminology used when talking about towing.  I have compiled a small list of key words and their definitions.  Hopefully this helps people better understand how you can successfully tow a trailer, be it an RV, horse or utility trailer.  The science behind towing is all the same.

First thing to be aware of is this; Because a tow vehicle and a trailer form an articulated (hinged) vehicle, weight considerations are very important to safe towing. The tow vehicle must be a proper match for the trailer.

The ball and coupler hitch is used on a wide variety of tow vehicle combination. This hitch consists simply of a ball attached to the rear of a tow vehicle and a coupler (socket) at the tip of a tongue or A-frame attached to the front of the trailer. This hitch is commonly used on recreational trailers.

A load distributing hitch is used for heavier models such as utility trailers, boat trailers, and travel trailers. These load distributing hitches use special equipment to distribute the tongue load to all axles of the tow vehicle and trailer to help stabilize the tow vehicle. Here are some terms you should know when discussing hitch adjustment and in evaluating hitch performance:

* Receiver: Hitch platform fitted to the tow vehicle.

* Ball mount: A removable steel component that fits into the receiver. The ball and spring bars (only on load distributing hitches) are attached to it.

* Sway Control: A device designed to lessen the pivoting motion between tow vehicle and trailer when a ball-type hitch is used.

* Coupler: A ball socket at the front of the trailer A-frame that receives the hitch ball.

* Spring Bars: Load-leveling bars used to distribute hitch weight among all axles of tow vehicle and trailer in a load distributing ball-type hitch.

Regardless of what style of hitch you are using to tow with, Safety should always come first.  I can not stress enough about safety being at fore front on ones mind while towing, hitching up and even while unhitching at your destination. Some common safety items to think about are:

Perform a safety inspection before each trip: Make sure that the pin securing the ball mount to the receiver is intact, the hitch coupler is secured, spring bar hinges are tight with the safety clips in place (load equalizer or weight distributing hitches), safety chains are properly attached and the electrical plug is properly installed.

Practice trailer backing: Backing a trailer into tight places is easier than it looks, but it does take some practice. It’s best to practice in a parking lot and in a vehicle that allows you to see the trailer through the rear window. Vans, trucks and campers that have obstructed rear views require more practice and the use of side mirrors. In either case, be patient, and make steering adjustments slowly and a little at a time.

Watch your tongue weight: How a trailer handles down the road depends upon tongue weight. Too much weight will cause the rear of the trailer to sway and make the tow vehicle difficult to control. The tongue weight should not exceed 200 pounds for trailer up to 2,000 pounds. Tongue weight for trailers over 2,000 pounds should be 10 to 15% of the trailer’s loaded weight.

Take care of tires: It’s wise to periodically check tires for wear, cuts or other damage and replace as needed. Above all, maintain the tire pressure recommended by the manufacturer, located on the tire sidewall. Improperly inflated tires will cause them to wear out quicker and reduces fuel mileage.

Let us move on to some terms and abbreviations of weight that really confuse a lot of people.   I tried as best as one could to keep the definitions simple and plain. Not all apply to recreational vehicle towing.  However I thought it best to include as much information as I could.

* Base Curb Weight – Weight of the vehicle and trailer not including cargo or any optional equipment.

* Cargo Weight – Includes cargo, passengers and optional equipment. When towing, trailer tongue weight is also part of the Cargo Weight.

* Gross Axle Weight (GAW) – The total weight placed on each axle (front and rear). To determine the Gross Axle Weights for your vehicle and trailer combination, take your loaded vehicle and trailer to a scale. With the trailer attached, place the front wheels of the vehicle on the scale to get the front GAW. To get the rear GAW, weigh the towing vehicle with trailer attached, but with just the four wheels of the vehicle on the scale. You get the rear GAW by subtracting the front GAW from that amount. In the absence of a scale, calculate the Front Gross Axle Weight by adding the Front Axle Curb Weight to the Cargo Weight (including passengers) assigned to the front 1/2 of the van. Calculate the Rear Gross Axle Weight by adding the Rear Axle Curb Weight to the Cargo Weight (including passengers) assigned to the rear 1/2 of the van and the Tongue Weight of the trailer.

* Gross Axle Weight Rating (GAWR) – The total weight each axle (front and rear) is capable of carrying. These numbers are shown on the Safety Compliance Certification Label located inside the driver side door frame. The total load on each axle (GAW) must never exceed its GAWR.

* Gross Combination Weight (GCW) – The weight of the loaded vehicle (GVW) plus the weight of the fully loaded trailer. It is the actual weight obtained when the vehicle and trailer are weighed together on a scale.

* Gross Combination Weight Rating (GCWR) – The maximum allowable weight of the towing vehicle and the loaded trailer (including all cargo) that the power train can handle without risking costly damage. The measured GCW must never exceed the GCWR. (Important: The towing vehicle’s brake system is rated for safe operation at the GVWR — not GCWR. Separate functional brake systems should be used for safe control of towed vehicles and for trailer weighing more than 3,000 lbs. when loaded).

* Gross Vehicle Weight (GVW) – Base Curb Weight plus actual Cargo Weight. It is the actual weight that is obtained when the fully loaded vehicle is driven onto a scale.

* Gross Vehicle Weight Rating (GVWR) – The maximum allowable weight of the fully loaded vehicle (Base Curb Weight plus options plus cargo). The vehicle’s measured GVW must never exceed the GVWR. The GVWR along with other maximum safe vehicle weights, as well as tire, rim size and inflation pressure are shown on the vehicle’s Safety Compliance Certification Label.

* Gross Trailer Weight – Is the highest possible weight of a fully loaded trailer the vehicle can tow. It assumes a towing vehicle with mandatory options, no cargo and the driver only (150 lbs.). The weight of additional optional equipment, cargo and hitch must be deducted from this weight.

* Payload – Maximum allowable weight of cargo that the vehicle is designed to carry. It is Gross Vehicle Weight Rating minus the Base Curb Weight.

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One thought on “Towing terminology and guidelines.

  1. Pingback: Hitch up your 5th wheel and let’s roll. « RVing is Easy at Lerch RV

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