Ball Mount Basics: Weight Capacity, Class, and Size

Learn more about the following ball mount topics:Some of the most important considerations when choosing a ball mount include its class, weight capacity, and size. Unlike vehicle-specific hitches that must be compatible with your tow vehicle, there are no ball mounts designed for specific vehicles. Instead, ball mounts can be installed on almost any vehicle—as long as they are compatible with that vehicle's hitch, and as long as the vehicle's tow capacity is not exceeded. Note that a towing setup is always limited by its lowest-rated component, whether that be your vehicle, your hitch, or another component. Ideally, you should use a ball mount of the same size and equal or greater weight capacity than your trailer hitch so as not to be limited by your ball mount capacity. Fortunately, these weight and size ratings are organized into five classes that make choosing the right ball mount a fairly simple process.
Trailer Hitch Ball Mount by Curt

What Are Ball Mount Classes?

You have probably heard terms like Class I and Class V used to categorize ball mounts and trailer hitches—but what do these classes mean?The five classes are used to group ball mounts and hitches of similar sizes and weight ratings. For instance, a Class I hitch and ball mount will have a lighter load capacity and fit a smaller hitch than a Class V model. The best ball mount for you is going to be the ball mount that can support the load you want to tow and will fit into your trailer hitch.
Trailer Hitch Ball Mount Weight Class Chart
Pictured: ball mount classes and weight capacities

Which Ball Mount Class Do I Need?

Ball Mount Weight Ratings

Like hitches, ball mounts are categorized by two important weight capacities: gross towing weight (GTW) and tongue weight (TW). The gross towing weight is the heaviest loaded trailer that the ball mount can tow. The tongue weight is the maximum weight that a trailer can exert downward on the ball mount.Your ball mount capacity must meet or exceed the loaded weight of the heaviest trailer that you want to tow—the last thing you want is a ball mount that can't hold up under your tow load. The tongue weight capacity of the ball mount must also meet or exceed the tongue weight of the trailer. If you're not sure of your trailer tongue weight, you can easily measure it. Weigh Safe makes ball mounts with built-in scales, or you could also use a tongue weight scale, a commercial scale, or even a bathroom scale. For tips on how to determine your tongue weight using these methods, check out our how-to article on measuring trailer tongue weight.Once you know how much weight your ball mount needs to support, you can figure out which ball mount class is going to work best for you. If you already have a hitch of the proper weight rating, the best way to select your ball mount is to choose one of the same class as your hitch.
Tongue Weight Illustration

Fits 1¼ in. Receiver

Class I/Class II Trailer Hitch Ball Mount
  • Class I*
  • Class II*

Fits 2 in. Receiver

Class III/Class IV Trailer Hitch Ball Mount
  • Class III
  • Class IV

Fits 2 ½ in. Receiver

Class IV Trailer Hitch Ball Mount
  • Class III
  • Class IV
  • Class V

Fits 3 in. Receiver

Class V Trailer Hitch Ball Mount
  • Class V
*Note: Although both Class I and Class II ball mounts share a 1¼" hitch receiver size, many Class I hitches include a weld stop that prevents the use of Class II ball mounts. To avoid overloading the hitch, Class II ball mounts and accessories should never be used with Class I hitches. However, Class I ball mounts and accessories can be used with Class II hitches as long as the weight capacity of the lowest-rated component is not exceeded.Because hitch receivers are usually made in one of these four common sizes, finding a ball mount to fit your hitch is easy. Read on below to read more about the specific ball mount classes and capacities.
Trailer Hitch Ball Mount Class I Specs
  • Typical loads: kayaks, canoes, mobility scooters, and small trailers
  • Typical tow vehicles: compact cars, midsize cars, full-size cars, SUVs, and minivans
  • Manufacturers often recommend a specific ball mount be used with their Class I and Class II hitches
  • Class II acccessories, including ball mounts, will NOT fit Class I hitches. This incompatibility helps to prevent the overloading of Class I hitches. Manufacturers accomplish this by placing a stopper in the back of Class I hitchreceivers so that drawbars and accessory shanks can only slide into the trailer hitch opening up to that point. On Class II hitch accessories, the shank that slides into the hitch opening is longer. When this longer shank slides into a Class I hitch, it will hit the stopper, preventing the pin hole on the hitch from lining up with the pin hole on the accessory.
Hitch Pin Hole-Class I Tab
Trailer Hitch Ball Mount Class II Specs
  • Typical loads: kayaks, canoes, mobility scooters, small pop-up campers, small boats, and small trailers
  • Typical tow vehicles: compact cars, midsize cars, full-size cars, SUVs, and minivans
  • Manufacturers often recommend a specific ball mount be used with their Class I and Class II hitches
  • Class I accessories, including ball mounts, can be used with Class II hitches
Trailer Hitch Ball Mount Class III Specs
  • Typical loads: midsize campers, utility trailers, lawn maintenance equipment, kayaks, canoes, motorcycles, and snowmobiles
  • Typical tow vehicles: full-size cars, large SUVs, minivans, and trucks
  • An adapter allows you to mount hitch accessories made for a 1¼" receiver in a 2" hitch
  • The available range of capacities for Class III hitches varies quite a bit—from 3,500-8,000 lbs GTW and 350-800 lbs TW. Be sure to choose a ball mount with sufficient capacity to match your hitch and the load that you want to tow.
Trailer Hitch Ball Mount Class IV Specs
  • Typical loads: large campers, large boats, and toy haulers
  • Typical tow vehicles: heavy-duty trucks and SUVs
  • An adapter allows you to mount hitch accessories made for a 1¼" receiver in a 2" hitch
Trailer Hitch Ball Mount Class V Specs
  • Typical loads: large toy haulers, equipment haulers, multi-car trailers
  • Typical tow vehicles: heavy-duty and commercial trucks
  • A reducer sleeve allows you to mount hitch accessories made for 2" receivers in a 2½" hitch
Updated on: 3/1/21

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