How to Measure for Drop Ball Mount and Recommended Drop Ball Mount

Updated 06/29/2020 | Published 06/25/2020

Question:

I have a Karavan boat trailer for my 20 foot Bayliner. I have had the boat since August, and have only towed it from the person I bought it from then. It has yet to go into the water due to CV19. But I want to put it in the water on July 4th weekend. So, today I hooked it up to my SUV and I had to use a floor jack to get the ball to fall onto the receiver. And the trailer jack was useless to raise the nose of the trailer to fall onto the 2inch ball. Is there a way to raise the ball or is there a hitch that does not have the inch mine does? I think mine is a 3inch . I am thinking that if the ball were higher I could use the trailer jack to move it up and down and not have to pull out the floor jack every time.

asked by: George S

Helpful Expert Reply:

It sounds like you might need a rise/drop ball mount. The best way to determine what size rise/drop ball mount you need it so measure the distance from the bottom of your trailer's coupler to the ground, and then measure the distance from the top of your vehicle's hitch receiver to the ground. If the hitch height is more than the coupler you'll use this formula:

Hitch Height (A) - Coupler Height (B) = Drop (C)

If your coupler is taller than the height of the hitch you'll use:

Coupler Height (B) - Hitch Height (A) = Rise (D)

If you need a ball mount with a 3" drop you can use something like the # C45341. You may want to consider an adjustable ball mount like the Fastway # FA34FR which can be adjusted all the way down to 5-1/2" of drop or up to 7" rise. The Fastway is a great choice because of the built in tongue weight scale to make sure that you're never overloading your tow vehicle, and it's constructed of lightweight aluminum which will help fight off corrosion.

I've linked some informational videos on these parts that I recommend having a look at.

expert reply by: Erik B