Which 5th Wheel Base Rail Installation Kit for 2021 GMC Sierra 2500 with 6-3/4 Foot Bed

Expert Reply:

I have a solution for you, but the # RP50066 is not the correct bracket kit for your 2021 GMC Sierra 2500 Denali. Instead you'll need to use the Reese Quick-Install Custom Outboard Brackets for 5th Wheel Trailer Hitches # RP57FR, which are actually going to be easier to install because they're outboard mounting brackets so it's a great solution. If you need the base rails as well, you'll want the # RP84FR.

I've linked a review and installation video of these for you to check out.