How to Determine the Correct Height Setting for Ram Demco Autoslide Rails

Updated 01/22/2026 | Published 01/19/2026

Products Featured in This Question

Replacement Side Plates for Demco Autoslide 5th Wheel Trailer Hitch - Ram

(26)

$599.66

Question:

I just ordered the Ram OEM demco rails to mount on my demco auto slider hitch. I have a 2026 ram 3500 Big Horn with 20 in tires. the tailgate measures 39 in to the ground. I have a 2025 rockwood signature r374bh 5th wheel. which set of mounting holes should I use on the Hitch/rails?

asked by: James K

Expert Reply:

Hey James,

I can help get this sorted out and get you towing safely! To determine which setting to use for the Replacement Side Plates for Demco Autoslide # DM99GV, follow these steps:

1. Park your truck and trailer on level ground and then uncouple.
2. Level out your 5th wheel trailer front to back.
3. Measure from the ground to the bottom of the pin box plate - not the king pin (A).
4. Subtract your 39" truck bed measurement from your Step 3 measurement.

This will tell you the height setting needed for your Autoslide. You can also adjust your 5th wheel pin box up or down on its brackets to help fine-tune the fit. It doesn't have to be EXACT but you want it to be as close to exact as possible.

expert reply by: Josh B

5th Wheel Height Setting
(click to enlarge)

Kevin G.

1/21/2026

I purchased the side plates to bolt to my Demco Highjacker Hitch because I have the puck system in my 2020 Ram 2500. They are easy to bolt on. Great product to keep from having to drill holes in my bed and mount rails in my truck. I have been using mine for 5 years now without a single problem.

Josh B.

1/22/2026

@KevinG thanks for that insight, five years with no issues says a lot! Having the OEM puck system makes a huge difference when you're installing the hitch. I'm glad the Hijacker is treating you well!