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  1. Gooseneck and Fifth Wheel Adapters
  2. Demco
  3. Gooseneck Hitch to Fifth Wheel Trailer
  4. Connects to Gooseneck Hole
  5. Hitch Adapters
  6. Adapts Truck
Demco 5th Wheel Base Rails Adapter for B&W Turnoverball Gooseneck Hitches

Demco 5th Wheel Base Rails Adapter for B&W Turnoverball Gooseneck Hitches

Our Price: $649.00
You Save: $118.00
Gooseneck and Fifth Wheel Adapters
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Shipping Weight: 86 lbs
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Install this adapter in the ball hole of your B&W Turnoverball gooseneck hitch to get above-bed base rails for your fifth-wheel trailer hitch. Universal rails provide attachment points in your truck bed for a standard fifth-wheel hitch. 1-800-940-8924 to order Demco gooseneck and fifth wheel adapters part number DM6140 or order online at Free expert support on all Demco products. Great prices and Fastest Shipping for Demco 5th Wheel Base Rails Adapter for B&W Turnoverball Gooseneck Hitches. Gooseneck and Fifth Wheel Adapters reviews from real customers.
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  • Reviews (59)
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Demco Gooseneck and Fifth Wheel Adapters

  • Gooseneck Hitch to Fifth Wheel Trailer
  • Connects to Gooseneck Hole
  • Demco
  • Hitch Adapters
  • Adapts Truck
  • Fixed Height
  • No Offset

Install this adapter in the ball hole of your B&W Turnoverball gooseneck hitch to get above-bed base rails for your fifth-wheel trailer hitch. Universal rails provide attachment points in your truck bed for a standard fifth-wheel hitch.


  • Adapter mounts in your gooseneck trailer hitch to supply the above-bed base rails necessary for installing a 5th-wheel hitch
    • Works with B&W Turnoverball gooseneck trailer hitches
    • Compatible with Demco Hijacker Premier Series, B&W, Curt, Draw-Tite, Hidden Hitch, Husky, Reese, and Valley above-bed 5th-wheel trailer hitches
  • Adjustable mount allows for bed mats and liners
  • Fast, easy installation
    • Drop adapter into gooseneck ball hole and lock in place
  • Sturdy, black powder coated steel resists corrosion
  • Made in the USA
  • 5-Year limited warranty


  • Gross towing weight: 21,000 lbs
  • Vertical load limit: 5,250 lbs


  • Do not use this adapter with the Demco Hijacker Autoslide hitch or any other automatic sliding fifth-wheel trailer hitch.
  • Do not use this adapter with a B & W Patriot slider fifth-wheel hitch.
  • Demco Hijacker 5th-wheel hitches manufactured before 2012 do not fit industry standard universal rails.
  • When using this adapter, you may have to remove the safety chain loops from your gooseneck hitch if they are mounted front/back rather than side to side.

6140 Demco Base Rails w/ B&W Ball Adapter for 5th Wheel Trailer Hitches

Item # DM6140

Installation Details DM6140 Installation instructions

Customer Satisfaction Score:

Customer Reviews

Demco 5th Wheel Base Rails Adapter for B&W Turnoverball Gooseneck Hitches - DM6140

Average Customer Rating:  4.8 out of 5 stars   (59 Customer Reviews)

Install this adapter in the ball hole of your B&W Turnoverball gooseneck hitch to get above-bed base rails for your fifth-wheel trailer hitch. Universal rails provide attachment points in your truck bed for a standard fifth-wheel hitch.


I like this adapter. It drops right in to where my turn over ball goes, secures just like the turn over ball with one added bolt for extra security, and the the hitch mounts to it. It is easily removed so that I can still quickly utilize a goose neck with my turn over ball. I rate this model a 4 star as it only works with 2 widths of hitches. My original hitch did not work but bought one that did. The 2 sizes are relatively common sizes. I recommend this for those that do not want to remove their turn over ball hitches and want a quick and easy way to move from 5th wheel to gooseneck connection.


Excellent product, however the packaging was completely compromised & the single wall cardboard bow was completely destroyed! Luckily the damage was minor given the material of the product. I’d recommend having a packing Eng design a better enclosure!


Great customer service and quick delivery. Fits perfectly in my B&W turnover gooseneck hitch!

Perfect solution for me! Easy to install and remove when not needed. It doesnt move around when towing. Im very pleased with the performance and price.
Tim K - 09/15/2021


Product had minimal set up, and works perfectly. As for etrailer staff, they are consistently great.

Sorry for delay in answering, my wife and I are very happy with product.
Patrick - 01/25/2022


The adapter dropped right in, it is nice and snug,works great


The ordering process and tracking the package are by far the easiest in the industry!


When my truck came with a gooseneck hitch, I didn't want to get an adapter for the trailer. This adapter fit perfectly and allows me to mount my fifth wheel hitch to the truck and remove it when I'm not using it. The hitch and adapter together are REALLY heavy; it'll take a forklift or 2 or 3 strong people to take it out.


Robert in customer service answered my questions about the product and took my order. Arrived in 2 days as stated with no packaging issues. Had it installed in 30 minutes or less after reading instructions and them mounted 5th wheel hitch to it. Installation was straightforward. As there is a torque specs for adjustment/lock bolt I
suggest having torque wrench availiable for proper installation. Only reason for not giving a 5 star rating is have not pulled 5th wheel rv yet to see if it has any slack


This is my second adapter. I tried the Curt X5 first and had problems with it fitting. But etrailer worked dilligently with me to find a solution. Ultimately refunding my money on the X5 and suggesting this Demco product. It fit and worked perfectly in my truck. Thanks etrailer for your help.

Perfectly. One of the best purchases and customer experiences I’ve had. Thanks you etrailer.
Jeff B - 12/21/2017


This adapter plate when used with the B&W turnover ball hitch allows me to use a gooseneck trailer, fifth wheel trailer, and also use a truck camper. My original Fifth wheel bed rails were interfering with installation of a truck bed camper and this eliminates that problem. Installation is very fast and only requires torquing of the single center bolt after placing the adapter lug into the socket. I had zero problems installing this unit and it only takes about a minute to do. Also the paint job is very durable.


item was exactly as represented, fit as it should, delivered on time.

this is not a quick exchange if you need to remove and reinstall for each use, but the product has been good, works just as it should.
Stephen - 02/22/2022


Heavy and Built like a tank. One to three people will be needed in installing, one or two people to place in the flip over receiver and one person to pull the locking pin. Direct fit for the Demco Recon fifth wheel hitch.
Very well packed with all necessary parts securely attached to item.


It works great easy hook up and easy to install


This hitch mount is great! I can now swap over from my 5th wheel hitch to a gooseneck in minutes. This is a great product. I had a gooseneck hitch already installed in my pick up but needed to tow my 29 foot 5th wheel. I other mounts to install the 5the wheel to my 2013 Ram but the gooseneck hitch mount was in the way. Found this set up on line at . Fast shipping, Ez to get my order in. 100 % satisfied. Plug and play. Took less than 10 minutes to install.


This product worked great. Used it in a 2016 Ram 2500 4x4 with the B&W turnover ball. The only problem is the safety chains for the B&W wont let this set flat against the bed of the truck. I solved this problem by using a heavy duty 1/4 inch rubber bed mat between the bed and this bracket and cut the rubber around the B&W hole and safety chains. That helped take up the extra space and helped to protect the spray in bed liner from being rubbed. Had no problems towing my fifth wheel and was happy I don't have these rails permanently mounted in my truck bed.


Fantastic product and fantastic service. I ordered on Monday and received at noon on Wednesday.


I am fairly unhappy with the fact that I can not use this 5th wheel rail system with my b and w gooseneck chain hooks installed. I have to unbolt the chain hooks to get the rails flush in the bed. I specifically asked if this was compatible with my set up prior to order. Pretty upset that it turned out different than what I was told. The rails are nice, but I did not want to have to modify my set up each time I want to hook up a gooseneck trailer. Hopefully this will help others in their research.


Quick and Easy to install holds up good just pulled my fithwheel back from Louisiana to the house in Alabama running 70/80 the whole way held up good no slack in it the only thing I wish was a lil deff is when I go from gooseneck ball to hitch I have to remove my safety chain loops out of my bed so it allows a flush mount but that’s about it overall a great product


It works perfectly with my B&W turnover hitch and Reese 20k 5th wheel hitch.


Fantastic product, perfect fit both in the turnover gooseneck and the rails for my plate , easy install but do wish they'd cut slots in for the safety chain u-bolts as I had to remove those to make it sit flush.


The adator I purchased is a great piece of engineering. Instalation was very easy. I am very happy with it so far. Have not towed my 5th wheel yet but will soon.
The only thing I can suggest to etrailer is the packaging. The cardboard box was broken open on one side and retaped. In a few places the paint was chipped off. I repainted the chips before installation so they will not rust.


It fits the truck and my fifth wheel hitch fits in it perfectly. Great product.


Fantastic customer service. Communication exceptional. Kept me informed about product, informed me that might be a delay in the original product ordered and suggested another like product that would ship sooner. Worked out perfectly. Would definitely recommend!


The adapter works great, it alow me to pull gooseneck trailers and my fifth wheel and still have a totally flat floor to carry cargo in the bed.


Was just what I was looking for I have a b&w flip over ball and couldn't put rails I with it so I went with the dm6140 to solve my problem and it worked perfectly thank you so much

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