What is the Measurement from the Top of the Bolt Hole to Bottom of Cast Head Coupler w/ Jack Hole?

Updated 08/07/2025 | Published 07/11/2025

Question:

DM37ZR interested in buying but need to confirm the dimension of the hole top to bottom of the rail. The reason is, my A-frame trailer structure of rails is 3inch wide and L shape, not square tubing. See picture of what width I need one for bolt on. Thanks

asked by: Stephen N

Measurement of Trailer Frame
(click to enlarge)

Expert Reply:

Hello Stephen,

I am always looking for a good excuse to stretch my legs (thank you), so I went out and got the measurement you requested, from the top of the bolt hole, to the bottle of the rail on the # DM37ZR is 1 9/16". I attached an image of the measurement as well, and also an image that a customer sent in that has the same style frame as you, he was able to get it bolted on.

What kind of trailer is this going on?

expert reply by: Kate F

Measurement on Demco Cast Head Coupler w/ Jack Hole
(click to enlarge)

Demco Cast Head Coupler w/ Jack Hole Installed
(click to enlarge)

Kate F.

8/7/2025

Hey Stephen, How did the installation go with the coupler on your A-frame trailer? I'm curious to know if the measurement worked out for you and if everything fit as expected. Let me know how it turned out, as it could really help others with similar trailers!