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

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

Item # DM8551005
Our Price: $455.14
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Fifth Wheel Installation Kit

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Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches. 1-800-940-8924 to order Demco fifth wheel installation kit part number DM8551005 or order online at Free expert support on all Demco products. Great prices and Fastest Shipping for Underbed Rail and Installation Kit for Demco UMS 5th Wheel and Gooseneck Trailer Hitches. Fifth Wheel Installation Kit reviews from real customers.
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2011 Ram 3500 - Underbed Rail and Installation Kit for Demco UMS 5th Wheel and Gooseneck Trailer Hitches

  • Below the Bed
  • Demco
  • Custom

Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches.


  • Installation kit is designed for use with Demco UMS 5th-wheel and gooseneck trailer hitches
  • Underbed rails allow for complete access to truck bed when hitch is removed
    • No exposed rails
    • 4 Mounting holes sit flush with truck bed
  • Vehicle-specific design reduces installation time and requires less drilling than universal systems
    • Brackets mount to the outside of your truck's frame rails - drilling is required
    • Crossmembers sit along top of frame rails, beneath bed
  • Sturdy, black powder coated steel resists corrosion
  • Rails and installation hardware included
  • Made in the USA


  • Application: Demco Underbed Mount Series (UMS) 5th-wheel and gooseneck trailer hitches
  • 5-Year limited warranty

8551005 Demco Hijacker UMS Under Bed Rail Frame Bracket Kit

Customer Satisfaction Score:

Customer Reviews

Underbed Rail and Installation Kit for Demco UMS 5th Wheel and Gooseneck Trailer Hitches - DM8551005

Average Customer Rating:  5.0 out of 5 stars   (7 Customer Reviews)

Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches.


These are very strong and helpful of being able to remove your hitch when not in use. Heavy Duty and out of site and with the plastic covers when the hitch is removed, you never know these are even installed. Comes with an awesome guide wire in order to bring the bolts to the holes through your boxed frame. Highly recommend these.


Easy installation. Just follow directions. We’ll made.







See what our Experts say about this Demco Fifth Wheel Installation Kit

  • Installation Of Demco Underbed Rail Kit On 2005 Dodge Ram With 8-Ft Bed
    The installation of the Underbed Rail and Installation Kit # DM8551005 is measured from the back of the truck bed. We do not have an installation video for the rail kit as you requested, but here are the instructions per the installation manual. I also attached the drawings referenced in the instructions you can check out. You can compare the brackets you said are on your truck to the measurements in the instructions. NOTE: It may make the install easier if the truck’s rear end was...
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  • Underbed Mounting Kit to Use Demco Hijacker 21K on 2009 Dodge Ram 3500
    The correct underbed rail kit for your 2009 Ram 3500 so that you can use the Demco Hijacker Autoslide # DM8550037 is the part # DM8551005. This is a custom kit for your truck which will help to reduce the aount of drilling and time needed to perform the installation, but we do still estimate a total installation time of around 4-1/2 hours. The brackets will mount to the outside of the truck's frame rails (where some drilling will be needed) and the crossmembers will sit along the top of...
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  • Recommended Rail Kit for Demco Hijacker Autoslide on 2011 Ram 2500 Short bed
    The Demco Hijacker Autoslide 5th Wheel Trailer Hitch # DM8550022 that you referenced is a great option for your 2011 Dodge Ram Pickup and it is designed to mount to custom underbed rails. This particular hitch will not work with above-bed base rails. For the underbed rail kit that is confirmed to fit your Ram and that will work perfectly with this hitch, you will need the Installation Kit # DM8551005. This kit includes all the brackets and crossmembers needed for installation. The frame...
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  • Recommended Autoslide Hitch for 2010 Ram 2500 Mega Cab
    Though an auto-slide hitch is not going to give you more front-to-back travel, it is extremely beneficial because of how simple it is to use and I highly recommend the auto-sliding Demco Hijacker # DM8550037 for your 2010 Ram 2500 Mega Cab. You can mount this hitch with the Underbed Rail and Installation Kit # DM8551005, which is a confirmed fit for your truck and has underbed rails so you can remove the hitch at any time and still have full access to your truck's bed. The Hijacker uas...
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  • Availability of Automatic Sliding Fifth Wheel Hitch for 2007 Dodge Ram 2500
    Yes, the Demco Hijacker Auto Slide part # DM8550022 can be installed in the bed of your 2007 Dodge Ram 2500 short bed and is an automatic sliding hitch that will slide back as you make tight turns. The rail kit you would need is the part # DM8551005 which is an underbed kit that will leave your truck bed less restricted when the hitch is removed that above the bed rail kits. This is a custom fit rail kit to which means it will install easier than a universal and will minimize drilling. I...
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  • Are the Installation Instructions Included with the Demco Hijacker Autoslide Hitch and Rails
    Yes, on both the Demco Hijacker Autoslide Hitch, # DM8550022, and the Underbed Rail Kit, # DM8551005, instructions are included with the products. You can also reference Demco's website for more information on installing their hitches. Installing the underbed rails will be the most labor intensive part of the installation process. You will have to measure and line up the where the location of the underbed rails will mount and cut holes in the bed of the truck for the mounting points between...
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  • Demco Underbed Fifth Wheel Rail Kit that Fits 2011 GMC Sierra 1500
    Demco does have an underbed fifth wheel rail kit that fits a 2011 GMC Sierra 1500 Denali with the part # DM8551005. You would normally use a Hijacker Autoslide part # DM8550037 with this rail kit.
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  • Underbed Auto Sliding Hitch for 2013 Ram 2500 Short Bed
    For an under-bed autosliding fifth wheel hitch solution for your 2013 Ram 2500 the best option is the Demco Hijacker Auto Slider part # DM8550022 and the underbed rail kit part # DM8551005 and you'd be set. Or if you need a higher 21k capacity hitch you'd want the part # DM8550037 instead. If your truck has a standard suspension height you'd have nothing to worry about. If you have a suspension lift beyond that it would really depend on how big of a lift the truck has.
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  • Sliding 5th Wheel Hitch With Most Clearance for 2012 Ram 3500 With Demco Underbed Rails
    I know it seems like the Hijacker # DM8550022 (assuming this was the autoslide you were referring to) may not have done its job but that isn't the case. This hitch offers 14 inches of travel, which is more than most. Here is the formula you can use to determine if any hitch will allow full 90 degrees of turning: (A+B) - C = Clearance A = Distance from the center of fifth-wheel hitch jaw to truck cab B = Length of Sliding Hitch Travel C = Width of trailer divided by 2 (to get half) At...
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  • What 5th Wheel Hitch Matches The Below Bed Rails On My 2004 Dodge Ram Pickup
    I did some online research it appears you have Demco below bed rails, part # DM8551005. I gave Demco a phone call and their representative confirmed it. I recommend one of the two Demco Hijacker Autoslide 5th Wheel Trailer Hitch w/ Slider - Single Jaw - Underbed, we offer. The differences between these two options are their weight ratings. They are the 18K Autoslide, part # DM8550022 21K Autoslide, part # DM8550037 The Demco Autoslide automatically slides rearward to give you an additional...
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  • Auto Slide 5th Wheel Hitch for a 2008 Dodge Ram 3500
    We have exactly what you need. The Demco Hijacker Autoslide 5th Wheel Trailer Hitch w/ Slider # DM8550037 is an auto slide 5th wheel hitch with a 21,000 lb. capacity and there is no need for a separate capture plate for standard pin boxes. This hitch would install in your 2008 Ram 3500 using the Underbed Rail and Installation Kit for Demco Hijacker # DM8551005. You may also be interested in the Curt 5th Wheel Custom Wiring Harness w/ 7-Pole Connector # C56001. This wiring harness will...
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  • Recommended Autosliding 5th Wheel Hitch And Underbed Rails For 2008 Dodge Ram 2500 Mega Cab 6 Ft Bed
    For your 2008 Dodge Ram 2500 Mega Cab with 6 foot bed, the Demco Hijacker Autoslide 5th Wheel Trailer Hitch w/ Slider - Single Jaw - Underbed - 18,000 lbs # DM8550022 is an excellent choice. This is a confirmed fit for your truck and will give you 14 inches of travel front to back. This will automatically slide for clearance on turns so there is no need to get out of your truck. The integrated rack and pinion gears create a controlled motion for a smooth driving experience. Cushioning...
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  • Recommended Automatic Sliding 5th Wheel Hitch for 2005 Dodge Ram 2500
    For your 2005 Dodge Ram 2500 with a 6 foot bed, I recommend the Demco Hijacker Autoslide 5th Wheel Trailer Hitch # DM8550022. This is a great hitch that will slide automatically to give you an additional 14 inches of clearance for making sharp turns. It features a premium wraparound jaw that will provide a secure connection with the trailer and a gross towing weight capacity of 18,000 pounds. To install the 5th-wheel hitch on your truck, I recommend the Underbed Rail and Installation...
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  • Compatibility of a Demco Hijacker 21K Under Bed Rails With a B&W Under Bed Gooseneck Hitch
    If you are installing the Demco Under Bed Rails, # DM8551005, for the 2011 Ram 2500 truck, then the B&W Under Bed Gooseneck Hitch, like # BWGNRK1313, will have to be remove to allow for the installation for the Demco Hijacker 5th Wheel hitch. The gooseneck hitch will interfere with the 5th wheel rails installation. The gooseneck mounting braces might cover the frame area where the 5th wheel brackets will need to be installed. Removal of the gooseneck hitch is necessary.
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  • Demco Fifth Wheel Rail Kit Recommendation for 2008 Dodge Ram 3500 for Demco Autoslider
    If the Demco Hijacker 16k is the version that attaches to their underbed style rails like part # DM8550022 then the custom install kit you'd need is the part # DM8551005. If instead the rails that the hitch installs in are the standard above the bed rails then the correct rail kit is the part # DM8552016-71. If you are unsure measure the distance between the mounting tabs on the hitch from front to back. If they are 22 inches apart you have the above bed style hitch. If not then you need...
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  • Recommended Demco Slider with Underbed Mounting Rails for 2011 Ram 3500 with 6.5 Foot Bed
    For your 2011 Ram 3500 6.7L Diesel with 6.5 foot box, the underbed rails you want for the Demco Slider are the Underbed Rail kit # DM8551005. This is a custom fit for your truck that will give you the underbed rails you need for either the 18K # DM8550022 or the 21K # DM8550037. You may also want to consider the wiring harness to add a 7-way to the bed of your truck like # DM8555002. This will give you a clean look and an easy connection access point. Let me know if you have further...
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  • Towing a Fifth Wheel Trailer with a 2007 Dodge Ram Mega Cab with a 6 Foot Bed
    You can tow a fifth wheel trailer with a 2007 Dodge Ram Mega Cab that has a 6 foot bed. Unless your trailer has a Sidewinder or Revolution pin box already you're going to need a sliding fifth wheel hitch. To install a hitch in your 2007 Dodge Ram use # RP50140-58 for the custom install kit. Another option is the Demco Hijacker Autoslide # DM8550037. The Hijacker travels 14 inches but the best part is that it slides automatically. No getting out of your truck to activate the slide feature...
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  • Auto-Sliding 5th Wheel Hitch For A 2005 Dodge Ram 2500 With A 6-1/2' Bed
    For your 2005 Dodge Ram 2500, I recommend the: -Demco Hijacker 5th Wheel Hitch # DM8550037 with the custom installation kit # DM8551005. This is an auto-slide 5th wheel hitch that is rated for a maximum towing capacity of 21,000-lbs, and features three height settings, so you can adjust the hitch to fit your application, and, has 14" of slide travel giving you the turning clearance needed when making sharp turns. We do not have any auto-sliding 5th wheel hitches rated for 20,000-lbs...
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  • Install Bracket Kit for Demco Hijacker 5th Wheel Trailer Hitch in a 2004 Dodge Ram Short Bed
    Whether your 2004 Dodge Ram is a 1500, 2500, or 3500 you have two options of bracket kits. If you're using the 18k Demco Hijacker for Above Bed Rails # DM8550034 you'll need # DM8552016-71. If your Hijacker is for Underbed Rails # DM8550022 use # DM8551005.
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  • Best Fifth-Wheel Trailer Hitch Options for 2007 Dodge 2500 Heavy Duty Quad Cab 4x4
    Because your truck has a “short” bed (6-1/2 feet), I recommend going with an automatic sliding hitch. An automatic sliding hitch, as opposed to a traditional sliding hitch, will allow you to make those sharp turns without having to get out and move the hitch yourself. Instead, the hitch will automatically adjust when you make a turn. I've attached a demonstration video of an automatic sliding hitch for you to check out. There are two main options for the automatic sliding hitch—an above-bed...
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  • Recommended Fifth Wheel for 2010 GMC Sierra 5-1/2 Foot Bed to Tow a 5th Wheel Camper
    It is possible to tow a camper with a 5-1/2 foot bed if equipped properly, which I can help you do. First thing you will want to do is make sure you find a 5th wheel hitch that is rated properly for your camper. Next with a short bed you will definitely have clearance issues with the truck and camper when making turns so you will want to make sure that you get a hitch that allows for extended travel like the 22-1/2 inch travel that the 13K Hijacker Demco 5th Wheel AutoSlide # DM8550040...
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  • Underbed Mount and Auto-Slider 5th Wheel Hitch for a 2006 Dodge Ram 2500 Quad Cab Short Bed
    Reese 5th Wheel Trailer Hitch # RP30051 is a manual slider hitch. For an auto-sliding hitch I recommend the Demco HiJacker # DM8550022. It can be installed on a 2006 Dodge Ram 2500 short bed with air bags using custom under bed installation kit # DM8551005. The frame brackets of this kit are narrow enough to not interfere with air bag mounting brackets. You mentioned adapter # RP30156 which is an adapter for Ford trucks with the factory 5th wheel prep package. It does not fit the 2006...
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  • Recommended Sliding Hitch and Rail System for a 2003 Dodge Ram 2500 w/ a Short Bed
    The best choice for a rail kit would be the Demco Premier Series Above-Bed Base Rails and Custom Installation Kit item # DM8552016-71. This is an above bed kit which is what you will have to install to use the 18k Demco Autoslider item # DM8550034 you were looking at. I strongly recommend this hitch. The Autoslider will give you 14" of travel for extra clearance when turning and backing. This is the most out of any sliding hitch. A 21K 5th wheel hitch is massive overkill for your needs....
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  • Can 2013 Ram 2500 Longhorn Diesel Tow 19,000-lb GVWR 5th Wheel Trailer
    According to the Ram Trucks website the 2013 Ram 2500 Longhorn crew cab with Cummins diesel engine and 6-speed automatic transmission has a maximum trailer weight capacity of 17,630-lbs. This covers your trailer's dry weight plus about another 2000-lbs, but it is still a good bit below your trailer's maximum GVWR of 19K. We always suggest having a healthy safety margin for any towing, 5th wheel or bumper pull, so in your case you might want to consider a lighter trailer if you expect to...
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Employee Lindsey S
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Expert Research:
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Updated by:
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