Curb Weight - The curb weight of a vehicle is the actual weight of a fully operation vehicle, including all fluids and in most instances at least a minimum quantity of fuel, but excluding any passengers, cargo, machinery, and equipment that does pertain to the normal operation of the vehicle. Curb weight can include equipment such as cranes, lifts, toolboxes, utility beds, and dump beds that are permanent parts of the vehicle's body.
Unladen Weight - The unladen weight of a vehicle is the actual weight of the vehicle when not carrying any load, i.e. cargo. Unladen weight and curb weight can be used synonymously. Whereas many manufacturer's publish curb weight, most motor vehicle governing bodies will refer to the unloaded weight of a vehicle as the unladen weight.
GVWR - Gross Vehicle Weight Rating.The GVWR is the maximum allowable weight of a vehicle and all its cargo (including passengers). GVW ratings are given to both trucks and trailers, but the ratings are independent of one another. That is, a truck's GVWR does not pertain to any trailer that is being towed. Likewise, the GVWR of a trailer has no relationship to the truck that is towing it. It simply identifies the maximum allowable weight of a single vessel.
Example - a truck has a GVWR of 14,000 lbs and a curb weight of 7,200 lbs. Therefore, the truck can haul up to 6,800 lbs worth of cargo and passengers.
GCWR - Gross Combined Weight Rating. The GCWR is the maximum allowable weight of the tow vehicle, trailer, and all cargo (including passengers). GCW ratings are given to tow vehicles, not trailers.
Example - a truck has a GCWR of 25,000 lbs and a curb weight of 7,000 lbs. If the truck is towing a trailer that weighs a total 15,000 lbs, the truck itself only safely haul 3,000 lbs worth of passengers and cargo. (25,000 lbs - 15,000 lbs - 7,000 lbs).
Maximum Payload - The maximum allowable weight that can be placed in or on a truck or trailer. Payload is calculated by subtracting the curb weight of a vehicle from the vehicle's GVWR, often including the weight of at least one passenger.
GAWR - Gross Axle Weight Rating. The GAWR is the maximum allowable weight that can be placed on an axle. The GAWR is specified for both the front and rear axles (steer and drive axles).
GTWR - Gross Trailer Weight Rating. The GTWR is the maximum allowable weight of a trailer and all its cargo. GVWR is often used in place of GTWR; the two ratings are synonymous with regard to maximum allowable trailer weight.
Example - a trailer has a GTWR of 15,000 lbs and a curb weight of 4,000 lbs. Therefore, the trailer can safely haul a maximum 11,000 lbs worth of cargo.
Maximum Tongue Weight - The maximum weight that can be applied to a hitch by the tongue of a trailer (this rating is applicable to any hitch type; bumper pull, 5th wheel, gooseneck, and pintle). Generally, the closer an item is placed towards the tongue of the trailer, the greater the trailer tongue weight. Tow hitches, receiver hitches, and trailer hitches will all have a maximum tongue weight rating. In instances where the rating of one of more hitch components varies, the rating of the lightest rated component must be obeyed.
Hitching, Loading, & Securing
Once you’ve hitched up to a trailer, always verify that the trailer hitch is properly secured. Ball-and-socket type hitches can seem to lock in place when in fact the ball is not properly seated in the socket. If this occurs, the trailer is at risk of bouncing off the hitch while driving. All trailers must be attached to the tow vehicle by an adequate chain system as well as an emergency trailer brake system to stop the trailer in the event of a break-away. Furthermore, the trailer hitch lever should be secured by a pin or lock so that it cannot gyrate loose while driving; a bolt and nut is not an appropriate hitch pin as the nut can vibrate loose.
There are many considerations regarding weight distribution when loading a trailer. First and foremost, always obey the ratings provided by the truck and trailer manufacturer. It is ideal, especially on large trailers, to balance the load slightly forward of the trailer’s tires (60/40 ratio, for example) as this promotes the smoothest possible handling while towing. Too much weight on the tongue or at the rear of the trailer will cause both the truck and trailer to ride poorly, increase trailer sway, and may even result in the trailer having control over the tow vehicle, making it difficult to handle. Loads should also be balanced from side-to-side to maximize safety and ride quality.
Your load is not worth anyone’s life, and as such securing anything to a trailer or in the bed of a pickup comes with heavy responsibility – take it seriously and always double, even triple check all ropes, straps, and binders. It’s also not a bad idea to pull over periodically and check to ensure the load is secure on longer trips. Always secure a load in all directions; the load is going to be influenced by various forces. The suspension is going to push the load up and down and side-to-side, while braking and acceleration is going to apply forces forward and backwards. When hauling vehicles or equipment, it’s best to secure a load from four individual points being pulled in four different directions (pulling at each of the four corners, for example). Doing so ensures that if a single chain/binder or strap should come loose, the load is still secured at three points. And finally, always secure the handles of chain binders to keep them from coming loose (tie wire, duct tape, or chain tails all work).
• Set your trailer brakes before you need them. Electric trailer brakes are simple to adjust, simply apply the brake while coasting slowly and increase/decrease the braking force as necessary. You should be able to hold the tow vehicle with the trailer brakes. Put the truck in drive, fully engage the trailer brakes using the brake controller, and then release the brakes of the vehicle. If the truck creeps forward, you likely need to increase your trailer brake force. Of course, you'll need to fine tune these settings after a few stops.
• When towing/hauling significant loads, rarely use overdrive. With automatic transmissions, using overdrive puts additional strain on the transmission, increases transmission fluid temperature, and you’ll likely be downshifting often in hilly terrain. Some manual transmissions also develop problems when the engine is “lugged”. If the tow vehicle is equipped with a “Tow/Haul” mode, use it.
• “Tailgating” is an unsafe practice, but it’s of even more concern when towing. Make sure to leave plenty of room between you and the vehicle in front if you. If you’re towing, your stopping distance can be increased significantly.
• Avoid parking on grades and always use your parking brake when you’re hitched to a trailer.
• Turn wide, trailers cheat! With every turn you make, your trailer is going to cheat towards the inside of the turn. The longer the trailer, the more it’s going to cheat, so plan accordingly. You should also avoid the inside left-hand turn lane – with large trailers, you’re likely to hit a curb or cut someone off.
• Slow and steady is the best way to tow. Don’t be afraid to go slightly under the speed limit if you feel unsafe of uncomfortable with the prevailing road conditions.
• Backing up a trailer is not something that can be taught from a text book, it requires experience. Remember that, when backing up, the trailer will respond to your steering commands by going the opposite direction. If you turn the wheel left, the trailer is going to go to the right, and vice versa. Keep an eye out for obstacles towards the front of the truck, as you might clip something if you’re only concentrated on what the trailer is doing. Finally, backup slow, use your mirrors, and have a spotter help you maneuver into position.
Before hitting the road, be sure to:
• Before hitching up, make sure that the ball or 5th wheel hitch system is properly greased.
• Check trailer brake lights, turn signals, and running lights.
• Check that trailer hitch, chains, and break-away system are all properly connected.
• Check that trailer brakes are functioning and properly adjusted (if applicable).
• Check that load is secured.
• Check truck and trailer tire pressures and condition.
• Grease trailer axle hubs routinely to prevent overheating and bearing failure.