Demco Underbed Rail System Dimensions for a 2016 GMC Sierra 2500

Published 08/13/2022

Products Featured in This Question

Demco Premier Series Above-Bed Base Rails and Custom Installation Kit for 5th Wheel Hitches

(12)

$437.51

Demco Autoslide 5th Wheel Trailer Hitch w/ Slider - Single Jaw - Underbed - 21,000 lbs

(740)

$2395.00

Underbed Rail and Installation Kit for Demco UMS 5th Wheel and Gooseneck Trailer Hitches

(14)

$477.27

Question:

I recently purchased a 16 GMC Duramax Denali and the previous owner had a 5th wheel hitch but took it out. The 6.5foot box has holes in it from a puck system?. I want to use those existing holes that are 28inch apart side to side and 11 3/4inch apart from to back. Appreciate any help!

asked by: Thomas L

Expert Reply:

Thanks for the picture! Those holes are not from an OEM puck system because the cab to tailgate dimensions are too short. It looks like the previous owner used the Underbed Rail and Installation Kit for Demco UMS 5th Wheel Hitches item # DM8551010. This system worked similar to an OEM puck system but only with Demco hitches. I have linked a dimensional drawing below for you to compare to what is currently on your truck. I have also attached an installation video.

Since your 2016 GMC Sierra 2500 is a shortbed you will need a slider that is compatible with the Demco Rails item # DM8551010. I recommend the Demco Autoslide 5th Wheel Trailer Hitch w/ Slider item # DM8550037. This is an autosliding hitch with a 21,000 lbs capacity.

expert reply by: Jerred H