How To Measure Hitch Drop

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When you tow a trailer, you want to keep your trailer coupler and tow ball as level as possible, beginning with using the right hitch and measuring hitch drop.

A hitch drop is a height difference between the vehicle receiver and the height of the coupler on the trailer’s tongue. Knowing this measurement will help you purchase the right hitch ball and keep the trailer level and safe when towing.

One of the first things to understand about safe towing is the connection between the trailer and the truck. Light-duty trailers have couplers on the tongue’s end that connect to a hitch ball that fits into a receiver. The coupler is locked into place on top of a hitch ball. While towing a heavy load is hard enough, towing can become more dangerous if the tongue and trailer level do not match. Considering that the NHTSA reports that over 55,000 accidents occur due to faulty vehicle and trailer hitches annually, it is easy to see how important it is to connect your hitch correctly. Let’s examine what a proper drop/rise is and why it is essential to understand this measurement when pulling a load.

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What Is Hitch Drop Or Hitch Rise?

Trailer hitch drop or rise is the difference between two measurements. The first is the distance from the top of the tow vehicle’s receiver to the ground. The subsequent measurement is the height of the top of the trailer’s coupler to the pavement (assuming both are on level ground).

To measure hitch drop or rise, subtract the coupler height from the tow ball hitch height. For example, if your tow ball height measurement is 13 inches, and the coupler height (when the trailer is level) is 8, you have a hitch drop of 5 inches. (Conversely, if the trailer hitch is 13 inches, but your trailer coupler sits at 18, you have a hitch rise position of 5 inches). Since trailers and ball mounts come in different sizes, knowing this information can make a world of difference when searching for the best way to connect your trailer.

How Do I Measure Hitch Drop or Rise?

You need to take two measurements to correctly identify the hitch rise or drop and the size hitch you need. You will want to ensure your truck and trailer are parked on level ground and are perfectly level. (I use a trailer kickstand to help keep the trailer tongue weight steady and off the ground).

Measure from the ground to the top of the shank/hitch receiver on the back of your truck. Then, measure the distance from the top of the coupler to the ground, and subtract the two numbers. The difference is the hitch rise or hitch drop.

What Are The Advantages of Knowing Hitch Drop?

If you examine the ball mount for a tow ball, you notice that they have a slight or definite bend. The ledge where the ball rests is lower (or higher) than the receiver, depending on how it is inserted. (The ball mount will have either a “Z” or an “S” pattern).

Having the capability to change the position on a standard ball mount means that you have two different hitch heights because you can change the ball’s position.

Another advantage is knowing your hitch drop helps your tow vehicle tow more efficiently by maintaining a level balance between the truck and the trailer. As we mentioned, if the connection point between the trailer and the tow vehicle is pointing downward (a V pattern), the weight of the tongue is likely to affect the rear axles of the lead vehicle. Too much weight means the trailer pushes the truck, affecting steering and braking systems.

If the connection between the trailer and tow vehicle points upward, the trailer’s tongue is lifting the truck’s back end and creating undue hardship on the trailer’s axle, resulting in excessive tire wear. This situation means that the trailer is subject to trailer sway, which is never a good thing when you are pulling a load. (The guy in the next lane doesn’t appreciate your trailer being blown into the side of his Prius).

Having a level connection minimizes strain and ensures neither the truck nor the trailer works harder than they need to. You will keep your truck from wearing out, see improved fuel economy, and keep your trailer where it is supposed to be - straight behind your truck’s rear bumper.

Do I Need More Than One Hitch if I Pull Multiple Trailers?

No, you don’t have to buy more than one hitch (unless you like spending the money). There are two types of adjustable ball mounts. The tow ball mount is rotated in the receiver tube depending on the ball hitch size. The other adjusts the ball up or down as needed.

One type of adjustable hitch will have different levels so the owner can move the ball mount up or down as more or less hitch drop is needed. Most adjustable hitches come with two or three different-sized balls, so you should be able to find a ball to match the coupler.

The trouble with a multi-ball mount is that it does not take into account any hitch drop or rise. These hitches work fine if the trailer’s coupler is the same height as the receiver but are not very effective if there is a difference between the two.

While a ball platform with adjustable options will cost more than a standard ball hitch, it can be a lifesaver when you need the ability to pull different trailers.

How Can I Be Sure I Am Purchasing the Right Ball Mount?

Since ball mounts and hitch balls come in different shapes and sizes, it is vital to know a few things before purchasing. Once you know your hitch drop/rise, the subsequent measurement is the ball size that is needed.

Determine The Size Of The Ball That You Need.

A trailer ball diameter should match the size of the coupler on the trailer you plan to tow. You can find the size stamped on the sticker of the trailer tongue, or you need to measure the inside opening of the coupler with a tape measure or ruler.  For example, a two-inch coupler opening requires a two-inch trailer ball.

Determine the Weight Capacity

Just because a trailer hitch fits into your receiver with the right rise hitch and looks great on the back of your truck doesn’t mean it can handle the load you plan to tow. Different hitches are made to tow different gross trailer weight, so you want to buy a hitch ball mount that can do the job. (You want to include the weight of the tongue, and the load, not just the weight of the trailer by itself).

Determine the Shank Size

You want a hitch ball mount with the correct hitch receiver opening. If the receiver tube and the shank on the ball mount do not match, you will have trouble hooking everything up to your tow vehicle.