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How to Measure for Trailer Hitch Drop
Written by: Amber S
Last updated: 5/20/2024
Est. read time: 5 mins.

How to Measure for Trailer Hitch Drop

For safe and comfortable towing, your trailer should always be as level as possible. A level trailer handles well, promotes even tire wear, and minimizes strain on both the trailer and tow vehicle. However, with the many different tow vehicles and trailers out there, it's rare that any vehicle and trailer line up perfectly for towing. This is why ball mounts are made in a variety of sizes and come with what's known as rise and drop — to compensate for the height difference between your trailer and vehicle and allow for safe, level towing. Today I'm going to show you how to measure rise or drop on your own trailer so you can get out of the driveway and onto the road!
In this article:
Learn how to measure for ball mount rise and drop with our expert Jake in this video!

What are Rise and Drop?

Rise is the distance from the top of the shank to the top of the ball platform when the ball mount is oriented for greater coupler height.Drop is the distance from the top of the shank to the top of the ball platform when the ball mount is oriented for lower coupler height.
Measuring Drop Hitch Rise
Measuring rise on your drop hitch
Measuring drop hitch drop
Measuring drop on your drop hitch
Keeping a trailer level
Your tow vehicle and trailer should be level when towing

How Do I Measure for Rise and Drop?

To choose a ball mount with the correct rise and drop, you'll first need to take two measurements: your hitch height (Measurement A) and coupler height (Measurement B). The difference between them will be your rise or drop.
Step 1: Find your hitch height
Measure trailer hitch height to top of receiver opening
Closeup - Measuring to top of hitch
Measurement A: With the tow vehicle parked on level ground, measure from the ground to the top of your hitch receiver opening.
Step 2: Find your coupler height
Measure coupler height from ground to bottom of coupler
Closeup of coupler measurement
Measurement B: With the trailer level, measure from the ground to the bottom of the coupler.
Step 3: Find the differenceDetermine which has a greater height—your hitch or coupler—and find the difference between the two measurements. This is the amount of rise or drop you'll need. Hitch Height (A) - Coupler Height (B) = Rise/Drop (C) If your hitch height is greater, use a ball mount with a drop. If your coupler height is greater, use a ball mount with a rise. You can flip your drop hitch upside down to use it in either the rise or drop position as needed. Example: (15" Hitch Height) - (10" Coupler Height) = (5" Drop Needed) (12" Hitch Height) - (13" Coupler Height) = (1" Rise Needed) Examples: Measuring for rise and drop on a fixed vs adjustable ball mount:
Measuring for trailer hitch rise or drop (fixed hitch)
Measuring for rise or drop on a fixed ball mount
Measuring for trailer hitch rise or drop (adjustable hitch)
Measuring for rise or drop on an adjustable ball mount

What If I Tow Multiple Trailers?

If you need to tow multiple trailers, you should consider an adjustable ball mount. While fixed ball mounts have a set rise and drop, the rise and drop on adjustable ball mounts can be altered to accommodate different coupler heights. Adjustable models can save you the trouble and expense of using a separate ball mount for each trailer. Simply slide the ball mount platform up or down the shank and secure it in place with the locking pin to achieve the necessary rise or drop.
Adjustable Trailer Ball Mount

How Do I Choose an Adjustable Ball Mount?

To choose the best adjustable ball mount for your towing needs, first you'll need to determine the tongue weight of the heaviest trailer you want to tow. Make sure your adjustable ball mount has the weight capacity to support the loaded weight of the trailer. Also make sure the ball mount you choose has the correct size shank to fit your hitch's receiver (for instance, use a 2-inch ball mount with a 2-inch hitch receiver). Next, determine the tallest rise and deepest drop you'll need using the guidelines above—this will be the range you'll need in your ball mount. Finally, determine which hitch ball diameter you will need. Adjustable ball mounts usually come with at least one ball, and most come with two or three balls of different sizes for towing different trailers.
Adjustable Trailer Hitch Ball Mount
Still have questions?Give our experts a call at 800-298-8924, or contact us online. We're happy to assist any way we can!
Amber S.
About the AuthorAs a content writer for etrailer, I might spend my morning loading and unloading a bike on five different bike racks to figure out which is easiest to use. I might be in the parking lot, taking pictures of an impressive RV battery setup our techs came across in the shop and discussing the benefits of the setup with the owner. I might spend an afternoon in a manufacturer training classes for some hands-on experience with new products, and then sit down to assemble all this information into a coherent article.At etrailer, one of our core values is that we are always learning, and I learn something new every day. I start each morning with the goal in mind of taking all of this information and figuring out the best way to answer the questions people ask us (and the ones they don’t know to ask yet), and helping people get the solutions they need to make their lives easier, safer, and more fun. I’m a DIYer at heart, so it brings me great joy to help a fellow DIYer find what they’re looking for, whether that’s a product, an answer, or a community.
Related ContentRelated ProductsWritten by: Amber S.Updated by: Jacob JUpdated on: 5/20/2024

Phil A.

11/29/2023

What effect if any do you get if tow ball is above top of hitch height. I’m currently having trouble with set up of my new car with van. I can get van level behind vehicle but rear of vehicle has about 80mm sag (too much) with WDH I put on 4 links but it only raises rear minimal. People recommend air bags but not convinced as sole way of solving problem. Sorry for more than one question. Thanks

Etrailer Expert

Jenny N.

11/29/2023

@PhilA Congratulations on the new vehicle! If you have too much of a rise on the ball mount it can cause the trailer to be off balance enough to cause uneven wear on the tires over time as the trailer front end will be up higher then it needs to be. With your vehicle sag, I would be happy to give options for you. Air bags can help however there are other options that may be better suited. How often do you tow? What is the year, make, and model of your new vehicle.

Phil

11/29/2023

@JennyN Hi, new car is Isuzu MUX, 2023, LST, we are full time travellers so towing most of year. I inquired about air bags, but people I speak to are either airbag or WDH supporters, I’m the latter as I have used them all the time. But I always have in my mind about airbags only lift but don’t move weight back onto front of vehicle and that is my concern. I previously had an Isuzu MUX 2014 model but new model is higher and whilst I can get van level on rear of car the rear is down about 80mm. That is when airbags are recommended but with my question about not shifting weight?
Etrailer Expert

Jenny N.

11/30/2023

@Phil Yep, you are correct in that using airbags will not shift weight however it will help with vehicle sag. You can use air bags and the WDH in conjuction with each other. The air bags PSI would be set first and then you would set the WDH. The draw back with air bags is that it takes a compressor which you can use a manual one or add a onboard compressor to your vehicle. That being said, for your vehicle I do not have an air bag system to offer through the manufacturers we carry except an universal kit rated for 1,000 pounds that would install in the rear coil spring suspension, such as part # AL60920. On the product page it explains how to measure to make sure you select the right kit if it is something you want to go with.
See All (5) Replies to Phil A. ∨

David K.

10/24/2023

What is the point on a towed vehicle do you measure? To figure rise or drop to correct offset.

Etrailer Expert

Mike L.

11/11/2023

@DavidK What's the year/make/model vehicle? Which base plate are you planning on using?

David K.

11/11/2023

@MikeL 2021 jeep grand cherokee 80th edition Using blue ox BX1128
Etrailer Expert

Mike L.

11/12/2023

@DavidK Assuming your GC is at stock ride height, the mounting arm tabs of the # BX1128 will sit at 17-1/2 inches above the ground. If this represents more than a 3 +/- height difference compared to the receiver hitch on the tow vehicle, you'll need the appropriate high/low adapter to bring it within that range. I'll link you to our selection of adapters below.

Terry Y.

9/29/2023

Great article! I may be over thinking this, but if I take my measurements and adjust the ball hitch accordingly to have them level, won’t the weight of the trailer push the bumper height down when the trailer weight is applied? It seems that if they line up level when not attached, they are both going to dive down (the front of the trailer and rear of the truck) once connected. I am new to this and may not be looking at it correctly. Thanks in advance!

Etrailer Expert

Mike L.

9/30/2023

@TerryY When choosing the height of your trailer ball, you'll want to allow 1-2 inches for the rear suspension squat caused by the trailer's tongue weight. You're definitely on the right track!

Robert D.

2/15/2024

@MikeL. Thanks for the tip. So to clarify, if I have a trailer that is 13” to the bottom of the coupler, and a 2020 ram 1500 where the receiver is 20” to the top, a 7” drop, I should use a 5” or 6” drop to account for the sag once I’m connected to the trailer?
Etrailer Expert

Mike L.

2/15/2024

@RobertD I'd go with the 5 inch drop. You'll sag an inch or two, but as long as you're within an inch or two of level, you'll be good to go!

Nivomat

8/16/2023

How does this math get affected by a vehicle that sags when not driven for a while due to air bags, or in this case nivomat self leveling shocks? Should you drive around for a mile or two loaded without the trailer, have it level out and then measure? Or do you measure while squatted and add a certain amount?

Etrailer Expert

Mike L.

8/16/2023

@Nivomat Good question. You'll want to have the vehicle level itself before measuring. Or, if you know how much the suspension lifts, add that measurement into the mix. Borrow a ball mount from somebody if you don't already have one, and see how much squat that causes and how the air suspension compensates for that. Use the hitch height measurement you get once the suspension adjusts to the trailer's tongue weight. If you have any questions, let us know!

Donm

1/13/2023

Excellent article, very detailed, simple to understand, and likely helped lots of people.

Etrailer Expert

Mike L.

1/18/2023

That's awesome, we're glad you found the article helpful!


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