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If your truck already has a B&W Turnoverball gooseneck hitch, this adapter gives you the fifth-wheel base rails you need without drilling or bolting into your bed. Just drop the Curt X5 5th Wheel Base Rails Adapter into the square gooseneck hole and lock it with the existing pin — no extra supports required. You get an instant set of above-bed rails ready for your fifth-wheel hitch.
The adapter provides an industry-standard rail (ISR) pattern compatible with fifth-wheel hitches from Curt, B&W, Demco Hijacker Premier Series, Draw-Tite, Hidden Hitch, Husky, Reese, and Valley. That means you can use a wide range of standard or sliding fifth-wheel hitches — including models rated for up to 20,000 lbs gross towing weight and 4,000 lbs vertical load limit.
This adapter’s sturdy steel construction is finished with a black carbide powder coat and liquid Aquence coating for durability and corrosion resistance. Rubber pads under each support foot keep the rails steady while helping prevent rattling or sliding in the truck bed. Once installed, the connection stays tight and stable for confident towing.
If needed for clearance, up to 1/4" can be trimmed from the bottom of the shank — as long as the locking pin hole still aligns properly. The square mounting tube centers directly over the gooseneck ball opening, keeping your setup balanced above the axle for consistent weight distribution.
Rated for 20,000 lbs GTW and 4,000 lbs vertical load limit, this adapter has the muscle to handle heavy fifth-wheel trailers while using the same underbed gooseneck system you already rely on. It’s a clean, removable solution that lets you switch between towing setups without losing bed space.
Customer Satisfaction Score:
91% were satisfied with this product
9% of customers were not satisfied
Ratings & Reviews
Joe S.
7/3/2016
Great. Works well to allow me to go from goose neck to fifth and back again with ease. Very satisfied!
Wayne H.
5/30/2016
It is great! Just got back from a 4800 mile trip and unhooked my fifth wheel and pulled the pin and removed everything from my truck bed. The only way to go!
Mike S.
5/7/2019
Works great, I had a Reese hitch left from my old 5th wheel and two pickups with the turnover ball in the bed. This is easy to install and solid when pulling. Just what I needed.
Eric S.
5/1/2018
Works perfectly and is very convenient.
Hutch
8/5/2017
Still going strong!
Terry H.
6/18/2016
Works great!
Tim
11/2/2022
Heavy duty, tight fit, no rattle. Thanks
Laurent
12/29/2018
100 Percent
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Lazer S.
5/13/2026
I am not aware of a way to adjust that, Eugene. Do you happen to have a bed liner? Those can cause this kind of thing to happen.