Ball Mount Basics: Weight Capacity, Class, and Size

Learn more about the following ball mount topics:

What Are Ball Mount Classes?
Which Ball Mount Class Do I Need?

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.

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.

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 III
Class IV
Class V

Fits 3 in. Receiver

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.

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.

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.

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

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

Shop Hitch Balls

Shop Tongue Weight Scales

Shop Hitch Pins & Clips

Hitch Ball Mount - Measure for Trailer Hitch Drop

How to Measure for Trailer Hitch Drop

Trailer Hitch Balls

Hitch Adapters and Extenders

Updated on: 3/1/21

Questions and Comments about this Article

Bernie S. 7/21/2021

Who/what defines the weight classes listed here? Those I see here are different from those found in SAE J684-2005 (IE class IV is 5,000-10,000 lbs in J684)

Reply from Jon G. 7/23/2021

There isn't really a standard when it comes to ball mount class ratings. Our article team basically lined this up with trailer hitch weight ratings so it's more of a range thing that has slight variants.

Mike 5/11/2021

2" Internal Thread Trailer Hitch Ball With 3/4" Shank, V5 3500 lb Brophy internal thread doesn't have a shank. requires a ball.

Reply from Jon G. 5/11/2021

Thank you for the clarification. Are you talking about something with a design like part # EI1C-C? This is a 1-7/8" hitch ball and I don't currently have a 2" ball with this style available.

Mike 5/11/2021

nothing to do with my comment. i was looking for a 2" threaded ball ( requires a bolt) and your picture shows a ball with threads the requires a nut. i need to use a 4" bolt for may application. picture does not fit ad.

Mike 5/11/2021

looking for a 2" ball that takes a bolt or threaded rod (off road aplication)

Reply from Jon G. 5/11/2021

I'm not sure if I know what type of hitch you're talking about but we do have an off-road application which you can find in the attached links. This is the Lock N Roll system which uses an articulating attachment point.

Helpful Links

dept-pg-a~frame_trailer_coupler-sf-off_road_coupler.aspx

dept-pg-straight_tongue_trailer_coupler-sf-off_road_coupler.aspx

dept-pg-trailer_hitch_ball_mount-pm-lock_n_roll.aspx