According to the Code of Federal Regulations, Title 49 - Transportation, § 571.3 - Definitions, the gross vehicle weight rating (GVWR) "means the value specified by the manufacturer as the loaded weight of a single vehicle."
Payload and maximum payload capacity are terms used to describe a vehicle's GVWR minus the weight of the vehicle, and minus all other weight applied to the vehicle: driver, passengers, specialty equipment, tongue weight of any items being towed, loads, etc.
Capacity is commonly used in conjunction with payload; for example, "What is my truck's payload capacity?" Capacity can also be used in reference to a spring capacity, such as "SumoSprings SSR-106-40's capacity is 2,600 pounds at 50% compression."
Where can I locate my GVWR?
The Code of Federal Regulations, Title 49 - Transportation, § 567.4 - Requirements for manufacturers of motor vehicles, requires a "manufacturer of motor vehicles...affix to each vehicle a label" that must contain the GVWR, along with other important information.
Trucks, Vans, Sedans
This label is usually affixed on the B-pillar of the vehicle.
This label is usually affixed to the wall adjacent to the driver seat.
Where can I locate my vehicle's maximum payload capacity?
Nowhere! No one can tell you your vehicle's maximum payload. If you visit a website that says "your maximum payload is 1,000 pounds..." close the window! As Smokey the Bear says, "Only you can" know your vehicle's maximum payload. Why? Because that website you're on does not know how much you weigh. It does not know how much your lumbar in the bed weighs. It does not know you have four passengers on board. Remember, your maximum payload is constantly changing depending on how much weight you have on board. Your vehicle's maximum payload is the GVWR minus specialty equipment such as winches or heavy duty bumpers, minus the driver, minus the passengers, and minus any other weight on the vehicle. Here is an example:
Specialty Equipment (bumper, wheels, in-bed tool box, etc.)
Load (Driver, Lumber, and tools)
Why is the payload capacity 2,000 pounds?
Because the GVWR (5,000), minus speciality equipment (1,000), equals 4,000 pounds. 4,000 pounds minus the load (2,000), equals 2,000 pounds.
This is an illustration. It is by no means intended to be a realistic example.
What is the difference between GAWR, GCWR and GVWR?
Now that you know what GVWR is, let's learn about GAWR. According to the Code of Federal Regulations, Title 49 - Transportation, § 571.3 - Definitions, the gross axle weight rating (GAWR) "means the value specified by the vehicle manufacturer as the load-carrying capacity of a single axle system, as measured at the tire-ground interfaces." Then there is gross combination weight rating or GCWR, defined as, "the value specified by the manufacturer as the loaded weight of a combination vehicle."
Will SuperSprings or other helper springs increase my GVWR?
No. Nothing can increase your GVWR. It is set by the manufacturer of the vehicle. It should never be exceeded. There is no suspension product in the world that can increase GVWR.
What is the capacity of:
SuperSprings have an arch. If you were to take the ends of the SuperSprings, apply pressure down, and turn the arch into a straight line, this is how we rate their capacity. The amount of weight it takes to remove the arch, to flatten the SuperSprings, is what we call "Additional Load Leveling Ability," their capacity. SuperSprings vary in capacity from light duty applications to extremely heavy duty applications.
SumoSprings capacity is determined by how much weight it takes to compress the spring down to 50% of its original body height.
Coil SumoSprings are used on a variety of original equipment and after market coil springs. There is no way to provide individual capacities for every application. Coil SumoSprings have been tested on numerous coil springs and all of those results indicate an increase of 15% to 30% in coil capacity.