Mounting Hole Spacing For the 5th Wheel Adapter Rails C88KR 16027 in a 2021 GMC Sierra 2500

Updated 04/09/2025 | Published 07/20/2023

Question:

Can I get the slot dimensions on the rails for 16027 adapter? I would like to see if my hijacker hitch will fit your rails. Adapter would be for a 2021 GMC 2500

asked by: Harry W

Expert Reply:

The Adapter Rails # C88KR (16027) will fit the OEM prep in your 2021 GMC Sierra 2500 and provide you with industry standard mounting points. As long as your Hijacker hitch uses industry standard rails, then it will work with the # C88KR adapter.

I have also included a diagram that shows the spacing of the slots in the Adapter Rails # C88KR.

expert reply by: Scott S

Adapter Rail Mounting Point Spacing
(click to enlarge)

Chris

4/9/2025

Scott, what is the space from front rail to back rail? I have a reese recever

Jameson C.

4/9/2025

@Chris 22 inches like what your Reese hitch is designed to fit. This is a dimension that is measured from the front hitch slot center to the rear one.