What Is A Tow Ball?

Last updated on September 11th, 2019 at 08:04 pm

A tow ball is a crucial part of a tow hitch system, and it’s immediately obvious where the name comes from – it’s the metal ball that sticks out and upward from the hitch bracket and this is where the trailer coupler gets linked up to.

The tow ball itself is made up of a metal ball with a narrower shaft which is usually threaded at the end. Midway down the shaft is a flange or collar, which holds the tow ball up from the ball mount at the proper height. The threads on the bottom end of the shaft let you add a washer and a nut to securely faster the tow ball to the ball mount arm.

Tow balls are also often referred to as hitch balls, trailer balls, and other similar names. 

Tow balls, due to their design, serves a variety of important roles as part of a trailer system. Their round shape makes it possible to link a receiver hitch to a trailer coupler even if the vehicle and trailer are not perfectly aligned.

The ball shape also makes the whole trailer hitch setup flexible so that the whole thing can make turns or go up and down slopes. The tow ball also helps the vehicle and trailer to navigate through bumps and uneven terrain by allowing the trailer link to pivot or rotate to a certain extent, as well.

Finally, tow balls can be easily removed if not in use and reinstalled as needed. Some trailer hitch and gooseneck setups also let you fold down and stow away the tow ball to get it out of the way. Pintle hitch setups can also use removable pintle balls so the owner can easily switch between regular and heavy duty towing applications.

Tow Ball Sizes:

Tow balls are available in a variety of sizes, and when you begin to consider what the size and length of tow ball you need to get for your setup, you generally need to look at three things: Ball diameter, shank diameter, and shank length. They are available in a variety of different standard sizes, so you need to choose the right tow ball for your trailer setup and the application

To find out the appropriate ball size and make for your trailer setup, you can consult the owner’s manual for more information. Many trailer systems will also have a reference plate that will list the tow ball size and the maximum towing capacity the kit is designed for, which should help you find the right tow ball to match.

Trailer kits may also have this information etched or engraved somewhere on the hitch frame, or on the tongue or coupler where they are readily seen.

Tow balls are used in trailer hitch setups as well as gooseneck hitch systems, and it’s very important to pick the correct ball size and shank diameter for the kit you plan to use for towing. Standard tow ball diameters include those as small as 1-7/8 inch, as well as the standard 2 inch tow ball. Larger tow setups may use 2-5/16 inch tow balls or larger.

Shank diameters, the most common ones anyway, include regular ¾ inch, 1 inch and 1-1/4 inch sizes to match most ball mount hole diameters. Tow balls also come in a variety of shank lengths, but the actual length may not be listed on the kit itself.

To ensure that you are getting the right tow ball for your trailer hitch setup, it’s always a good idea to measure the ball mount itself first. You want to make sure that you have enough shank length left, with the ball mount thickness taken into account, in order to fit the lock washer and locking nut.

You will also need to consider the towing capacity that your hitch ball can provide you, as well. As you might expect, larger hitch ball and shank diameters will give you larger capacities.

Tow Ball Finishes:

Tow balls are available on the market in a variety of materials and finishes as well, and they all offer their own advantages and disadvantages. Chrome-plated tow balls, which are steel balls with a chrome coating applied to them, are a popular option for owners looking for an economical towing accessory that also looks good at the same time.

The chrome offers corrosion resistance, as well – but when the chrome plating starts to wear off, the tow ball may become vulnerable to rust spots.

Chome Tow Ball (homedepot.com)

Stainless steel tow balls, on the other hand, are a good deal more expensive than other tow balls. On the other hand, they are very durable components that can withstand extensive use and still maintain water and salt resistance. Like chrome plated tow balls, they also have an attractive shiny finish as well.

Zinc tow balls – that is, steel tow balls with a zinc coating come with a duller silver gray finish that stands up well to moisture and salt content. They offer similar performance and corrosion resistance as stainless steel balls, and they also cost significantly less, too. Nickel coated tow balls are comparable to zinc tow balls when it comes to corrosion resistance, and both finishes are also more environment-friendly compared to chrome components.

Tow balls are also available with powder coated finish, and these finishes are highly durable finish options that you can get in a color that matches the rest of the ball mount. Many of the one-piece ball and mount designs on the market today offer this option.

Powder Coated Tow Ball (curtmfg.com)

Finally, tow balls that are made of heat treated or forged steel will have superior durability and strength compared to regular steel. Forged steel tow balls are also available without a surface finish, and these “raw” components are some of the most cost-effective options you can get for your towing setup.

What Size is a Standard Tow Ball?

Tow balls are available in a variety of standard sizes, and the majority of them are based around the 2 inch tow ball, which is the most common ball size for tow bar setups.

A 2-inch tow ball with a 1 inch shank diameter is the usual option for a lot of hitch setups, and most of your options in this range will give you a towing capacity of around 3,500 to 8,000 pounds. The 2-inch tow balls on the market today may also come with thinner ¾ inch shank diameters, or thicker 1-1/4 inch shanks for even more pulling weight capacity.

Smaller tow balls are also available for lighter duty towing, and they are mostly meant for systems that use interchangeable ball kits that are designed for towing trailers of different sizes. 1-7/8 inch tow balls are available with different shank diameters, and they are capable of towing up to 2,000 pounds or so. For tow balls of this size, your choice mostly comes down to a 1-inch shank diameter, or a smaller ¾ inch shank.

For heavy duty towing, you need a larger tow ball to match, and this is where the 2-5/16 inch tow balls come in. They also come with proportionally thicker shanks, and you can get them with 1 inch as well as 1-1/4 inch diameters.

Depending on the shank diameter and the make of the tow ball, one of these can offer you anywhere between around 6,000 pounds to as much as 40,000 pounds. Serious heavy duty tow bar setups and gooseneck systems may use even larger balls, and one of these can be as large as 3 inches in diameter.

What Does Tow Ball Height Mean?

The tow ball height is the distance between the ground and the center of the tow ball. The tow ball height depends on a variety of factors, such as the form and make of the vehicle as well as the design of the trailer hitch and the ball mount.

The design of the tow ball contributes to the tow ball height as well, and you can get high rise tow balls to give you a bit of extra tow ball height compared to standard rise balls. High rise tow balls can give you an extra inch or two of height – not that much at first glance, but the difference can be enough to get you within the prescribed tow ball height for your towbar design as well as the towing regulations in your area.

What is the Standard Height of a Tow Ball?

Trailer couplers are made to sit at a standard height, and this is the standard range you want to have your tow ball height set to. Most of the bumper pull trailers you will encounter will be set up in a way such that the ball height is at 16 to 17 inches off the ground.

Keep in mind that most ball height specifications are meant for laden vehicles – that is, with the vehicle slightly lowered by the load weight. If you are measuring your tow ball height on an empty vehicle, then you will usually end up with a higher ball height. In any case, you want to have the tow ball height of your setup within this standard range, since this ensures that your tow bar, trailer coupler and the whole system in general is close to level.

Keeping the whole setup level keeps the towing forces aligned, which is particularly important whenever you are climbing slopes or when the towing vehicle is braking. A level hitch will force the momentum of the trailer perpendicular to the ball, while a misaligned setup may cause the trailer to either dip down, or worse, lift the trailer up and pop the hitch off the tow ball.

What Is a Tow Ball Weight?

The tow ball weight or tow ball mass is a measure of the weight bearing down into the tow ball. The tow ball weight also describes the overall force that the trailer exerts downwards onto your tow hitch setup, and gives towing equipment manufacturers as well as owners a common standard for specifying the towbar download capacity of a tow hitch system.

The tow ball weight is measured using a ball weight gauge, which is a simple spring loaded device that is calibrated to measure the weight exerted by a trailer at the coupler end. You will need a trolley jack or trailer jack to lift the trailer first so you can get the ball weight gauge under the coupler, and to gently lower the trailer coupler so you can get your weight reading.

You may also see tow ball weight or tow ball mass referred to as the nose load, tongue load or the static vertical mass for you hitching system.

What is a Tow Ball Limit?

The tow ball limit is the maximum legally specified load limit for your hitch setup and your vehicle. As such, the tow ball limit varies between one vehicle model to another, as well as from one tow hitch setup to the next. To find out what is the tow ball limit for your vehicle, you’ll need to refer to your owner’s manual to get this information.

Once you have the tow ball limit for your vehicle, you will also need to check the tow ball limit for your towing hardware. You may be able to read this off the information plate on your tow bar, or you can refer to your towbar manual for more details.

To get the most stable towing setup, most experts recommend arranging your trailer contents such that 10 per cent of its total weight is applied to the hitch. If you’re towing a 3,000 pound trailer, for example, you will want a tow ball weight of around 300 pounds. 

You can reduce your tow ball weight within this range by putting your heaviest items directly over the trailer axle – for example, you can mount a tractor such that its center of mass is directly over the wheels of the flatbed trailer. To increase the tow ball weight, you can roll it slightly forward and closer to the hitch.

A well-balanced setup, within the tow ball limit and towing capacity of both the vehicle and the hitch setup, is easier to drive and less susceptible to swaying at speed. Take the time to get the right tow ball weight for your load and you’ll have a towing setup that will travel safer on the road.

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