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.

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 rise on your drop hitch

Measuring drop on your drop hitch

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

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

Measurement B: With the trailer level, measure from the ground to the bottom of the coupler.

Step 3: Find the difference

Find the difference between the two measurements. Determine 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.

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.

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!

About the Author

As 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.

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Written by: Amber S.

Updated on: 11/25/20

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!

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!

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?

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.

Mike L.

1/18/2023

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

Helpful Links

ball-mount

Luna

7/27/2022

I bought a stealth hitch and tow package which says the top of the ball measures 18" but my light (~1500lbs loaded) trailer specs read the top of the 2" ball should sit about 15" from the ground, are there any drops that are compatible with the stealth hitch?

David B.

7/27/2022

Is it 15 inches with the loaded trailer coupled? Or is it 15" up to the coupler while on level ground? There will always be some sag in suspension when you load up a trailer. What year/make/model is your BMW? If your trailer is completely level from the ground up to the coupler at 15 inches and your car is 18 inches that is a tolerable difference. We always want the trailer to be "level" but it will never be perfect. 3 inches up or down is going to be ok. I wouldn't go past 3 inches though.

Rick Z.

4/21/2022

When you hook the trailer to the vehicle, the vehicle drops almost 2 inches. Doesn't this change the height of the hitch measurement?

David B.

4/21/2022

Nope, you measure the hitch receiver while unloaded and the coupler on the trailer while it is level. The difference between the two measurements is the drop/rise that you will need. If the hitch drops 2 inches once coupled that means the the trailer tongue is dropping 2 inches and they will still be level. Let me know if you have any more questions Rick!

Steve K.

3/25/2022

My Chevy Colorado has a hitch height of 19" and the U-Haul trailer I'm going to pull on Sunday has a coupler height of 18". But I'm having trouble finding a ball out with a 1-in drop that fits my 2-in receiver. If I just get a standard 2-in drop starter mount will that extra inch make much of a difference?

Les D.

3/28/2022

@SteveK that one inch will not make a big difference. I don't think they make a one inch drop ball mount due to the thickness of the materials needed to construct it. I have placed a link of the smallest ball mounts below. I think the closest one is the Curt # C45020 linked below.

Helpful Links

dept-pg-trailer_hitch_ball_mount-sf-fixed_ball_mount-hs-fits_2_inch_hitch-pc-rise_~_1_inch.aspx

Mike L.

2/4/2022

Hello, I have measured both heights. The vehicle hitch height and the coupler height on the trailer are both 13 3/4". The ball is 2". Not sure what to use for a trailer hitch with a 2" ball.

Les D.

2/7/2022

I would go with the Curt # C45002 Solid Ball Mount for 2" Hitches. Includes both 2" and 2-5/16" Hitch Balls and is rated for - 10,000 pounds.

Mike L.

2/7/2022

@LesD Thank you.

Charles R.

1/12/2022

we talk a lot about sway with the hitch - what i want to know is how to adjust the bounce of trailers and suv

Les D.

1/12/2022

@CharlesR I would like to help. I assume this is a bumper-pull trailer rather than a fifth wheel. What model is it, and what weight? Also, what kind of truck are you pulling with?

Eddie G.

10/13/2021

I think people should be measuring the height on their vehicle with it loaded. If you load your vehicle with several hundred pound of gear plus people that back end is going to drop at least a couple or more inches. Plus the tongue weight of the trailer. I see a lot of setups going down the road where the hitch is to low.

Les D.

10/18/2021

@EddieG Yes, the truck and trailer should be fully loaded as you intend to travel, and they both should be level as you travel down the road. The truck should not be sagging without the trailer hitched. The 200 pounds of gear you mentioned should not create any significant sag. Now compare the truck receiver to the trailer coupler. if it does not match, then use a ball mount whose offset matches the difference between your truck and trailer. If after hitched up you have sag at the back of your truck, then you need a weight distribution hitch to move some of that weight back to the trailer and to the front axel of the truck.

Eddie G.

10/19/2021

@LesD I never said "200 pounds" I said several hundred. I have seen quite a bit of sag on some vehicles just loaded with people.

Terri

9/21/2021

Top of receiver on Jeep Grand Cherokee is 21. Bottom of coupler is 18. Would need a 3 inch drop but we have a 3 1/2 “. Trailer is approx 3000 lbs and tongue weight approx 300. Since I’m only off 1/2 inch, do you think there would be a problem? Tow capacity is 6200 lbs.

Les D.

10/18/2021

@Terri A 1/2" difference will not make a difference. The 300 pounds of tongue weight should not move you much. If after fully loaded (truck and trailer) you then see sag, then you may want a weight distribution hitch, especially if this is a travel trailer that may catch the wind.

Wayne M.

8/11/2021

I need a 1.5 in drop but they don't sell any. Just wondering if I could us a 2" drop as there lots of those. Thank you in advance for any help.

Victoria B.

8/17/2021

If the trailer that you are towing has a really light tongue weight, I would go ahead and go with a ball mount with a 2 inch drop as it will get you closest to level. If the trailer that you're towing has a heavy tongue weight that is going to sag the rear end of your vehicle, then I would lean more toward a multi-ball mount that doesn't have any rise or drop, like the TowSmart Multi-Ball # TS74FR. If the rear of your vehicle sags about an inch when the trailer is loaded, a ball mount with no drop will still help the trailer tow level.

16" H.

7/27/2021

I had a hitch installed on my subaru impreza 2006, which I bought from this site with a 1 1/4" receiver. I need a 16" hitch height to tow a 'droplet' trailer but I'm having trouble finding something with enough rise for a 1 1/4" receiver. What are your recommendations? The hitch height seems to be at just over 9" to the top at this point. I cannot seem to find a ball mount with 6" or 7" of rise for a 1 1/4" receiver.

Victoria B.

7/30/2021

I have a solution for you, but this will only work if the trailer you are wanting to tow has a coupler that fits a 2 inch diameter hitch ball. If this is the case, I recommend using a drawbar with a 5 inch rise, like # 36065, partnered with the Curt RockerBall Shock Absorbing 2 Inch Hitch Ball # C94CR. In addition to improving the experience of towing a trailer, this hitch ball also sits 1-1/2 inches above the ball mount thanks to the rocker base. This would make the total rise of your ball mount and hitch ball 6-1/2 inches. However, if your trailer coupler fits a 1-7/8 inch hitch ball, unfortunately we only have standard hitch balls that don't offer any additional rise. So a 5 inch rise is the tallest we could get in that situation.

Karl

7/11/2021

If I’m within 1.75” of being level with a straight lock n roll hitch, do I need to buy the 2 1/2” drop receiver, or am I ok with the straight receiver that comes with my trailer? Taxa Trailer height is 21” and my 4Runner is 19.25”. Thanks.

Jon G.

7/12/2021

I would get the drop receiver so that you're within 1" of level instead of almost 2".

Nima

7/11/2021

My trailer (magic tilt) sits at 14 and the hitch (Mercedes 2018 gle350) sits 15.5". I can't decide what drop I should get. the Minimum is 2" but with extra tongue weight not sure if BM20 or BH20 would be the right fit.

Jon G.

7/12/2021

Either one would work just fine for you. The main difference between the 2 ball mounts is that one of them has a 1" diameter hole for the shank of the hitch ball while the other has a 1-1/4" diameter hole for the shank of the hitch ball.

Fabio S.

5/28/2021

Muy interesante el tema. Gracias me ha servido mucho para mi proyecto.

Roy

5/10/2021

I'll be towing a 2021 Nucamp tag xl boondock (teardrop) with a 2012 Kia Sportage which I believe the hitch receiver is at 13". Per manufacturer the trailer tounge height at level is 21 inches. Which type of ball mount do you recommend?

Jon G.

5/10/2021

From what you said that means you need a ball mount with an 8" rise. You could use part # C45112 or one of the adjustable options in the selection that I've linked for you.

Helpful Links

dept-pg-trailer_hitch_ball_mount-sf-adjustable_ball_mount-pc-rise_~_8_inch.aspx

Kevin S.

4/22/2021

i will be towing a 2014 spark with a tow bar behind my 2015 Itasca sonova class a motorhome do you have any reference and how much of a drop down reciever i will need???

Jon G.

4/22/2021

I honestly have no idea. I do have a different help article that you can check out though which I am attaching. This is geared more towards the measurements needed for a tow bar setup as opposed to the ball mount setup that you're looking at with this article.

Helpful Links

faq-high-low-adapter.aspx

Stephen P.

3/24/2021

Ken, Sorry, but I meant the adjustable part to be a given, but would I likely need a 6" or 10" drop?

Kef G.

3/25/2021

There are several heights of trailer tongues, so recommending a specific drop would be difficult. You should try to find a ball mount that has a sizeable range to account for those differences.

Stephen P.

3/20/2021

I just bought a 2021 Silverado 2500 with the Z71 package. This truck sits higher than most 1500's I've seen. The top of the receiver is 23 inches off the ground. I believe I need a drop hitch, but don't have anything to compare to yet. I expect to rent a trailer in a month or so and want to be prepared. I also plan to buy a camper 3-4 years down the road. Is there an 'average'? I'm guessing a 6' adjustable drop, but don't want to buy one, then something else later because this didn't work.

Kef G.

3/23/2021

You could get an adjustable ball mount. They give you a couple of positions so you can match them with a variety of trailer heights. I've linked to a list of them below. You'll just need to match what size hitch you have and what size ball you're expecting to use.

Helpful Links

dept-pg-trailer_hitch_ball_mount-sf-adjustable_ball_mount.aspx

Aaron C.

3/18/2021

How does this take into account for the weight of the trailer weighing down the tow vehicle. Would make since that you would need to measure with the trailer with a slight decline front to back as when the hitched the tow vehicle will dip a bit. Maybe not significant enough to make a difference. Thoughts?

Jon G.

3/18/2021

While it is true that there will be a slight decrease in the height of the nose of the trailer, it really shouldn't be that significant to make a difference. Also, if your trailer weighs at least half the curb weight of your tow vehicle you should really be using a weight distribution system anyways which would keep everything level.

Aaron C.

3/18/2021

@JonG Ok. I don’t think I’ll have an issue but it’s a good suggestion to check curb weight. Thanks for your help.

Jon G.

3/18/2021

@AaronC Happy to help!

Erica

3/16/2021

My trailer sits at 18.25 and my hitch sits at 18.75 does a half inch difference matter?

Jon G.

3/18/2021

If you're already within 1/2" of being level then I wouldn't worry about that. In all actuality your setup will probably be level once you hook up since the back of your vehicle will likely have a little bit of sag to it with the weight of the trailer tongue weight pushing down on it.

Erica

3/18/2021

@JonG that's what I thought but just wanted to check! Thanks for answering

Rick L.

1/12/2021

Do these measurements also apply for an RV and TOAD?

Jon G.

1/18/2021

Yes and no. A recreational towing setup is a little different because the tow bar is going to connect straight to the base plate kit as opposed to a hitch ball sitting inside the coupler. The same principle will apply for a recreational towing setup though. You will want to take these measurements and make sure that your tow bar is within 3" of being level. Here is an FAQ about the tow bar side of things that you can check out.

Helpful Links

faq-high-low-adapter.aspx

Dave G.

12/12/2020

If the drop is 7" should I choose a 6" or 8" drop?