GVWR - Definition, Purpose and How to Determine Gross Vehicle Weight Rating
The GVWR (gross vehicle weight rating) is a safety regulation used to prevent the overloading of vehicles. It's the maximum safe operating weight of a truck, including its net weight, plus driver, passengers, cargo, and fuel. The gross vehicle weight rating doesn’t change after a manufacturer determines it for a vehicle.The truck manufacturer determines rating by the combined weight of the strongest weight-bearing elements, like the axles, and the weaker parts, such as the tires, frame, and body. It determines the vehicle's class, which defines the regulations that it needs to obey. In some cases, drivers may need to have a certain type of license for driving a vehicle. Understanding GVWR, and following the proper weight classification limits, helps to ensure your safety along with those who share the track with you.
What is GVWR?
It is a weight rating that applies to vehicles that fit into the different categories, from light pick-up trucks to trucks towing large tractor-trailers.The GVWR is a weight listed by the vehicle manufacturer that can be boiled down to the maximum amount of vehicle can weigh. It includes the vehicle’s passenger’s weight, cargo weight, and unloaded curb weight. If a truck's gross vehicle weight rating is listed at 9,000 pounds and it weights 4,000 empty, then its payload capacity is 5,000 pounds. It can be broken down into one rating classification compiled of two separate elements:
- the base curb weight of the vehicle;
- the weight of optional truck accessories, cargo, driver, and passengers.
GVWR consists of 8 separate weight classes which cover three commercial truck categories. Here’re the official numbers:
- Class 1 - 0 to 6,000 pounds;
- Class 2 - 6,001 to 10,000 pounds;
- Class 3 - 10,001 to 14,000.
- Class 4 - 14,001 to 16,000 pounds;
- Class 5 - 16,001 to 19,500 pounds;
- Class 6 - 19,501 to 26,000 pounds.
- Class 7 - 26,001 to 33,000 pounds;
- Class 8 - 33,001 pounds or more.
Operators in this category must obtain a Class B CDL to drive the truck.
How to Calculate GVWR For Trailer?
You can calculate gross vehicle weight rating by adding numbers into this formula:
GVWR vs GAWR
It’s the maximum operating weight, a number that's defined only by the manufacturer of the truck. Gross vehicle weight rating includes every part of the truck/trailer, such as the body, chassis, engine, fuel, accessories, etc. This information must be displayed on the vehicle.Typically, it’s displayed on a metal data plate that can be found on the vehicle’s doorjamb or the inside of the doors on both sides of the power unit. Plates or labels that display gross weight must stay legible since trucks are exposed to different weather conditions. Manufacturers generally opt vehicle weight rating durable metal data plates to ensure readability during the vehicle’s lifespan. On the opposite side is the GAWR (gross axle weight rating). This number deals only with tire size and inflation pressure as they correspond to single axles. Due to this, each axle has its unique GAWR typically accompanied by 'RR' (rear wheel) or 'FR' (front wheel).
GVWR vs GCWR
GVWR is the overall weight of the truck (including payload), while GCWR (gross combined weight rating) is a specialized weight rating that can only be determined by the manufacturer of the chassis.GCWR is established by the manufacturers of the chassis, based on the corresponding SAE International guidelines. A vehicle’s GCWR can be determined by taking both the total weight of the trailer and the total weight of the vehicle. These weights added together, make up the final GCWR. Usually, the GCWR is used in vehicle testing to define a range of safety trials, primarily, the braking capacities for the towing vehicle.
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Curb Weight vs GVWR
It’s pivotal to remember that the difference between the truck's curb weight and gross vehicle weight rating isn't a real number of the vehicle’s payload rating. You have to consider the weight of the cargo and the following elements:
- The “Tongue Weight” of a trailer.
If you’re not sure about the truck’s curb weight, you can find out at any weigh station. Be sure to put all the load you carry in the vehicle to get the most accurate estimate of the vehicle’s actual weight.Also, there should be a gross vehicle weight rating on a sticker on the driver's side door frame or in the owner's manual. Simple formula (GVWR minus measured curb weight) shows precisely how much cargo you can carry or how much the trailer’s tongue weight can be.
What is the Tongue Weight?
It’s the downward force that the trailer’s tongue exerts on the hitch that’s connected to the truck. Less tongue weight can cause the back end of the vehicle to lift, which can result in a severe condition known as trailer sway.On the other side, too much tongue weight can cause the back end of the truck to sag which negatively effects the handling of the truck, the driver's visibility, and the effectiveness of the vehicle's brakes. Most industry experts agree that an acceptable tongue weight is between 10 to 15 percent of the GTW (gross trailer weight). So, if you are towing a 6000 lbs trailer, the tongue weight should be measured at approximately 600 lbs.
What is GVWR on a Trailer?
If the truck’s capacity is rated at 11,000 pounds (determined by the axle capacities), and the trailer weighs 2,500 pounds, then your GVWR trailer capacity is 14,600 pounds. The capacity rating of your trailer is defined by subtracting the weight of the trailer from the gross vehicle weight rating of 11,000 pounds.
Trailer Hitch Types
Hitches are categorized in five classes:
- Class 1 – 2,000 lbs max trailer weight;
- Class 2 – 3,500 lbs max trailer weight;
- Class 3 – 5,000 lbs max trailer weight;
- Class 4 – 10,000 lbs max trailer weight;
- Class 5 – 10,000+ lbs max trailer weight.