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  1. Gooseneck and Fifth Wheel Adapters
  2. Bulldog
  3. Gooseneck Trailer to Fifth Wheel Hitch
  4. Replaces Inner Tube
  5. 30000 lbs GTW
  6. Gooseneck Coupler Adapters
Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube - Square - 30,000 lbs

Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube - Square - 30,000 lbs

Item # BD0289650300
Our Price: $199.94
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Gooseneck and Fifth Wheel Adapters
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Pull your gooseneck trailer with a fifth-wheel hitch by installing this square gooseneck-to-king-pin adapter. Inner tube fits most standard, square gooseneck coupler outer tubes. 1-800-940-8924 to order Bulldog gooseneck and fifth wheel adapters part number BD0289650300 or order online at Free expert support on all Bulldog products. Great prices and Fastest Shipping for Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube - Square - 30,000 lbs. Gooseneck and Fifth Wheel Adapters reviews from real customers.
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  • Reviews (358)
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Bulldog Gooseneck and Fifth Wheel Adapters - BD0289650300

  • Gooseneck Trailer to Fifth Wheel Hitch
  • Replaces Inner Tube
  • Bulldog
  • 30000 lbs GTW
  • Gooseneck Coupler Adapters
  • Adapts Trailer
  • No Offset
  • Adjustable Height

Pull your gooseneck trailer with a fifth-wheel hitch by installing this square gooseneck-to-king-pin adapter. Inner tube fits most standard, square gooseneck coupler outer tubes.


  • Gooseneck-to-5th-wheel adapter lets you tow your gooseneck trailer with a 5th-wheel hitch
  • Square inner tube fits most standard, square gooseneck outer tubes
  • Direct replacement for inner tube on Bulldog gooseneck-to-5th-wheel coupler adapter (BD0289590300 - sold separately)
  • Adjustable-height, 4-hole design
  • Durable steel construction
  • Raw finish


  • Overall tube width: 4"
  • Range of vertical adjustment: 8"
    • 2-3/4" From center of hole to center of hole
  • Usable length from top of tube to top of gusset: 19-7/8"
  • Pin hole diameter: 3/4"
    • Grade 5 3/4" x 5-3/4" through bolts (sold separately)
  • Plate dimensions: 11" x 14"
  • Weight carrying capacity: 30,000 lbs
  • Weight distributing capacity: 9,000 lbs
  • 5-Year limited warranty

Dimensions of adapter

Range of vertical adjustment

0289650300 Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube - Square - 30,000 lbs

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Customer Satisfaction Score:

Customer Reviews

Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube - Square - 30,000 lbs - BD0289650300

Average Customer Rating:  4.7 out of 5 stars   (358 Customer Reviews)

Pull your gooseneck trailer with a fifth-wheel hitch by installing this square gooseneck-to-king-pin adapter. Inner tube fits most standard, square gooseneck coupler outer tubes.


Great product, fast shipping, excellent communication, definitely recommend these guys!!

We painted the square tube/king pin tube red and installed it. Works great, but there is not much of it to see in the pic. Take my word, well built & very heavy duty!!

Tim S.


Product works great, shipping was fast and installation was very easy. Quality built and very heavy duty. I would definitely purchase it again, thanks.


I ordered this product and received it 3 days later, I took about 1 hour to remove the gooseneck tube and install this one and get the height set for towing, removed it once again and painted it due to it being bare metal. So far this seems to be a quality product.



After a year’s worth of towing with this hitch I’m loving it, I’ve put many thousand miles on the set up and love the stability it adds to my tow. The product is very well built and I haven’t had a single problem with it. If your considering this product don’t hesitate its well worth the money.


Received faster than expected.


Nice part and excellent communication.


put it on but have not used it yet. Everything looks great. Had too drill the holes out to 1 inch, but I new that when I brought it. this trailer will be pulling 4 race cars, a mod. 2 mini stocks, and a sport stock. get pretty hard rising old hitch above ball. drop the legs krank it down a little open the jaws, and leave . LOVE IT. Thanks easy shopping shipped when it was suppose to, and arrived.

Morris D.


still LOVE IT. thanks


A very nicely made heavy duty product. The welds are beautiful! You could mention the hole size for the lock pin in the ad. I had to drill them out to 1-1/16" for my application. The corners and edges were sharp on the king pin plate. I rounded them off. I am very pleased with the product, the speedy delivery and the price.



It was and is a great product. Im very pleased, The icing on the cake is the service you provide. You are my go to source when I need anything trailer related. I was pleasantly surprised by your follow up e-mail. Keep up the good work. Sincerely, TomDom518, Selkirk NY


It works well and makes the trailer hookup much easier! My only concern was with the box it arrived in as it was just rattling around in the box ripping holes throughout the cardboard, no damage to the item since it is literally bullet proof!

Etrailer Expert

Jenny N.


I will have our customer service team reach out to you.


I really like the king pin conversion over the goose neck for the ease of hooking and Unhooking. If I had a bigger truck with the regular fifth wheel it would've been great but I have the camper style fifth wheel that put center of gravity higher so it made my truck buck really bad. The only improvement I would make is to round The only improvement I would make is to round off The back two edges that are squared they get cought on my safety change when I turn sharp. I purchased an over over weight the bed ball plate from y'all and it works great


For the any amount of money you can't beat it....excellent product...I use it every day....switching from the 5th wheel hitch to the gooseneck hitch every time I used my flat bed was a real pain....the conversion hitch saves me tons of time and it saves my back from lifting that 5th wheel hitch off three or 4 times a month...


This slide in hitch pin has held up to my pulling very heavy loads for over a year. It installed easily and works well with my mid-range truck, even though I have a full size fifthwheel plate. It catches water when it rains and I would have liked it to be powder coated or painted so as to avoid rusting. I am very happy with the heavy duty welds and how thick the metal is on the shaft. overall it is well made and probably the best one on the market for the reasonable price.


A great option, I have two large 5th wheel trailers (RV & Gooseneck) and I tow them both with a short bed F350. With this setup on the Gooseneck, I can use the slider hitch and have no problems towing either trailer.


I have converted my Gooseneck trailers to 5th Wheel using this adapter. I have found out that the pulling is actually different in the sense of I am no longer as worried about going around a corner or being on un-even ground.

The trailer seems to pull much more straight and there is an increase in stability in my trailers...


Fit very well and welds looked good and quick shipping will recommend this product to anyone


The neck came in and looked great. Very heavily built and the welds look great. I am glad the kingpin is the same size as a tractor trailer hitch, as I have put this neck in my 32' tandem dual trailer. The trailer is heavy enough on a one ton truck empty, so it will now be used hooked to my Freightliner. The negatives I have are these... The neck holes are 7/8 and I needed them to be 1-1/8. I only needed the holes on one side, as the other side has a set bolt. So I had to fill that side in so the bolt would secure to something.


I purchased a gooseneck adapter to install on a trailer I bought. I hadn't looked at the trailer and thought I needed a round tube so that's what I ordered. When I went to get the trailer I found out I needed the one with a square tube. All it took to get the correct one was to make a call and explain that I needed to send the wrong one back and get the correct one.
The next day I received the correct one and went to get my trailer. The customer service people were great to deal with. Adapter fit was great!


Item was purchased for my gooseneck trailer as a back up to change from a ball mount to fifth wheel mount to use on rental truck when mine was in for repairs. It arrived in two days and worked great.


Worked as described.


Thanks Etrailer for this item. Shipping was fast and the item arrived just as described. I ordered this item to go on my 2001 Take3 car hauler trailer. It had a gooseneck coupler on it and I needed to change it out to a kingpin or 5thwheel coupler. This item worked great. Only thing I had to do to it was paint it.


I purchased a 4 in.² king pin adapter for my gooseneck trailer, along with a pigtail adapter so it will connect to my semi tractor. I'm just a quarter-mile away from the trailer dealership in Grove city. They wanted $265 for the same two items that I purchased through e-trailer for much less along with free shipping, and I had it in two days! Who wouldn't be excited about saving $100 ? Thanks guys, I really appreciate it!


Just like everything I get from etrailer professional help and quality products Great 5 th wheel adapter


Product shipped very fast, installed in less than 10 minutes. Hooking to trailer now does not involve getting out multiple times, just back into kingpin get out lock fifth wheel and crank the jack. Very fast , I love it.


I am waiting for my trailer to be ready for pickup, but the unit fit my Pullrite universal type 3365 capture plate fit without any modifications. I did have to remove a few of the extra shims sent with the plate, but that is expected.

Pulliam industries said I may need a 3317 plate. They also said the 3317 plate will work on just about any adapter with a kingpin. My hitch came with a 3365, so I tried to find an adaptor that would work. I was successful.

The items ships raw steel and will be rusting when you receive it. I will paint it myself. I wish it was painted at the factory.


Gooseneck to 5th wheel adapter arrived and I was pleasantly surprised at how nicely it was made. Fit was perfect and all is as advertised! Very heavy duty !!!


Received the Gooseneck to fifth-wheel coupler (inner tube only, with 4" square tube) yesterday. It is heavy duty (1/4") steel and construction seems very good. Only down side is that it is NOT cleaned or painted. I removed a little surface rust, cleaned, and spray painted it.


Excellent, interchanges with my gooseneck hitch so I can trailer either way depending on equipment

Show More Reviews

See what our Experts say about this Bulldog Gooseneck and Fifth Wheel Adapters

  • Gooseneck To 5TH Wheel Hitch Adapters For A Trailer With 4" Bulldog 25,000LB Gooseneck Hitch
    The Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 will fit into the 4" square Bulldog Receiver Hitch on your trailer. This will allow you to be able to tow the trailer with your 5th wheel hitch. Be sure to use a Lube Plate # RP83002 to protect your hitch and quiet down the noise while driving. If your 5th wheel hitch is not rated for 25,000lbs or the maximum GVWR of the trailer, you may consider using the Curt Spyder Gooseneck Trailer Hitch # 16085. This will drop...
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  • Square Tube Gooseneck Coupler Adapter Recommendation
    We offer 2 square tube gooseneck-to-fifth-wheel coupler adapters, the Redline Coupler Adapter, # KPG5-Q25-IP, and the Bulldog Coupler Adapter, # BD0289650300. These are quality couplers that would do an excellent job. If I were choosing one of these couplers, I would go with the Bulldog coupler because it has a wider bottom plate similar to a fifth wheel pin box that will make more contact with the fifth wheel hitch. It also has a small curved lip at the front of the plate making it easier...
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  • Recommended Gooseneck to 5th Wheel King Pin Adapter for 33 Foot Enclosed Car Hauler
    The Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 is a great product and has an overall tube width of 4 inches. The pin hole diameter is 3/4 inch. We do not make these assemblies in house, so making one to your specs is not something we are able to do.
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  • What is the Width of the Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300
    The inside width of the Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 is 3-7/16" while the outside width is 4". If the inside width of your outer tube is about 3-1/2" then this coupler adapter won't fit. All of our other square inner tubes have the same 4" outer diameter. You may need to swap out your whole coupler for an option like part # BD0289590300 which is the whole adapter; inside and outside tubes. You can lock the king pin with part # e98896 and the inner...
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  • Recommended Wiring Conversion for Semi Truck and Gooseneck Trailer with Electric Brakes
    The Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter - Inner Tube # BD0289650300 will work with a Semi Truck Connection. For the light converter, I recommend using the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT and then the Brake Controller # 90195 and wiring kit # ETBC7. This will allow you to convert your trailer wiring into the wiring that will work with a standard 5th wheel or gooseneck trailer with 7-way trailer...
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  • Adapter Solution to Convert Gooseneck Trailer to Fifth Wheel King Pin
    We have gooseneck trailer to fifth wheel king pin adapters that would work great on your trailer but it really depends on what type of gooseneck trailer you have now. For example if you have a square tube gooseneck you could use the part # BD028965030 or for a round tube part # PKG5-R25-IP. Or you could replace the outer tube as well and use the Bulldog # BD0289590300. For an air to electric brake controller the Hayes part # HA100400C is the kit you want. This ties into the air brake setup...
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  • Availability of Inner Tube Gooseneck to Fifth Wheel Adapter that Measures 4-1/2 inch by 4-1/2 inch
    I wish we did, but everything we carry has an inner square diameter of 4 inch by 4 inch. If the outer tube of your setup is 4-1/2 inch by 4-1/2 inch then the inner tube part # BD0289650300 could potentially be what you are looking for. You would need to measure the opening at the bottom of the outer tube though.
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  • Gooseneck Hitch Tube for 4-Inch Gooseneck Tubing
    It sounds like your gooseneck trailer is fitted with a square coupler/adapter tube such as # BD0289650300. This adapter fits a 4-inch inner diameter square gooseneck tube and provides a 5th wheel king pin to fit into a 5th wheel hitch. If you want to return the trailer to a gooseneck tube for a 2-5/16-inch ball you can use 4-inch square inner tube Bulldog BX1 Gooseneck Coupler # BD1289210300.
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  • Recommended Square Tube Gooseneck to 5th Wheel King Pin Adapter
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  • Adapters to Allow Towing Gooseneck Trailer with 5th Wheel Hitch and Base Rails
    If you have a set of industry-standard above-bed 5th wheel base rails in your truck you can tow a gooseneck trailer by installing an adapter such as the Curt Spyder # 16085 or the Curt 25k # 16055. All of these 5th wheel rail gooseneck adapters are standardized to fit into any brand of 5th wheel base rails. Note that some of these like the Pro Series have offset ball placement which gives you the option to install the plate with the ball either more forward or more rearward which alters...
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  • Availability of Gooseneck to 5th Wheel Hitch Adapter for 2015 Big Tex 25DU Gooseneck Dump Trailer
    If your truck has a fifth wheel hitch that uses industry standard rails (like those sold by Reese, Curt, Valley and Husky), the easiest way to tow the trailer would be to use a gooseneck ball that attaches to your bed mounted rails like the Curt # 16055. Big Tex tells me they used a Bulldog 4 inch square tube coupler on your trailer, so if your fifth wheel doesn't use industry standard rails, you'd need to remove the existing coupler and install the # BD0289650300 Bulldog Gooseneck to...
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  • What is the Exact Size of Bulldog Coupler Adapter # BD0289650300
    I went out and pulled one of these Bulldog Coupler Adapter # BD0289650300 and the measurements are as follows: the outside dimension of the adapter is an exact 4 inches. The inside dimension is an exact 3-7/16 inches. Another unit that we have that is a tad bit larger is the Bulldog # BD0289590300. This has an outside dimension of 4-1/2 inches and an inside dimension of 4 inches.
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  • Can a 5th Wheel King Pin Adapter be Installed on a Big Tex 22GN Gooseneck Trailer
    I looked up the Big Tex 22GN Gooseneck trailer and see that it has a square tube coupler. We do have an adapter, inner tube only, for square tubes, # BD0289650300. The tube is 4 inches wide on the outside. It uses holes for pins or bolts though so if the inner tube on the trailer now doesn't fit the same way then either the outer tube would have to be modified with permission from Big Tex or the adapter would have to be welded on and again with permission from Big Tex. There are other...
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  • Will 5th Wheel Trailer King Pin Fit Semi-Truck 5th Wheel Hitch
    Yes, the king pin on the Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter you referenced, part # BD0289650300, is the same size as that used on a standard semi- truck hitch. This 4-inch square gooseneck-to-king-pin adapter features a raw finish, adjustable height and weight carrying capacity of 30,000-lbs.
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  • Will Bulldog Gooseneck-to-5th-Wheel Trailer Adapter # BD0289650300 Fit a Peterbilt 5th Wheel Hitch
    Fifth wheel trailer hitches, even those on big rigs, accept the same size king pin so Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 will work with the Peterbilt 5th wheel hitch. I have linked a video review of this adapter for you.
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  • Swapping King Pin Setup on Kaufman Car Hauler Back to Gooseneck Setup
    I looked up several pictures of the Kaufman 3/4 car wedge and I couldn't find any that showed it having a fifth wheel king pin instead of a gooseneck. The ones I found all had gooseneck couplers which yours could have had swapped to a king pin setup but I'd have to see the setup to be absolutely certain. Most likely the trailer had a gooseneck setup like the part # BD0288660300 you referenced which has an inner and outer tube and a fifth wheel adapter was installed on it like the part...
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  • Can Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 Be Used with Semi Hitch
    The # BD0289650300 is rated at 30,000 lb and as long as you could mount it at the correct height for the semi truck fifth wheel hitch this would work just fine. The semi-truck king pin is the same dimensions as what this adapter offers.
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  • Will the Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter fit a 22 foot GN Big Tex Trailer
    The Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter # BD0289650300 that you referenced was designed to fit most standard, square outer tube gooseneck trailer couplers so it should work for you. You can verify that it would work by comparing the outer dimensions of this product with the current outer tube of your trailer. This has a 4 inch by 4 inch outer dimensions and should fit in the outer tube of your trailer.
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  • Gooseneck Hitch Recommendation for Peterbilt Single Axle Semi Trailer
    I do have a solution for you, however, the B&W Turnoverball # BWGNRC912 you referenced is not your best option. Instead, take a look at the Buyers Products 2-5/16" Fabricators Flatbed Gooseneck Hitch # 3375613500. This heavy duty hitch is designed to be welded onto a 1/8 inch, or thicker, floor plate and has a much smaller footprint than the BWGNRC912. The hitch plate dimensions are 6 inches wide by 8 inches long. It has a capacity of 30,000 lbs as well. I've included the installation...
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  • Adapting a Gooseneck Trailer to be Towed By a 5th Wheel Trailer Hitch
    All of the square inner tube gooseneck trailer to 5th wheel adapters we have are 4 inches wide so you will want to look at other adapter options. If your 5th wheel trailer hitch sits in above the bed rails then you can use a gooseneck plate, # 16055. I have linked a couple of videos of this hitch for you. If you do not have industry standard above the bed rails let me know what you do have and I can determine if there are other options.
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  • Recommended Gooseneck to 5th Wheel Hitch Adapter
    It sounds like your 5th wheel trailer already has what it needs and you just need the adapter for the Ram Gooseneck if I understand correctly. If your gooseneck hitch has a round tube, then I recommend the Gooseneck to 5th Wheel Trailer Coupler Adapter # KPG5-R30IP. If it has the square tube, then I recommend the Ram Gooseneck to 5th Wheel Trailer Coupler Adapter Inner Tube - Square - 30,000 lbs # KPG5-Q30IP which has a 4 inch tube. Both options have a plate that is 9-7/8 by 9-7/8 inches....
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  • Availability of Gooseneck Coupler to Fifth Wheel Hitch Adapter for 4-1/2 Inch Wide Coupler
    The best option I have that would work for you would be to remove the existing square outer tube from your gooseneck trailer and replace it with part # BD0289590300 which includes the outer tube that would weld onto your gooseneck and the compatible inner tube that would act as the adapter. When you tow a gooseneck trailer, you'd swap out the adapter and install a gooseneck coupler like part # BD1289210300. We retail the products shown on our website, we don't manufacture or fabricate...
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  • Recommended Adapter to Switch my 4" Square Gooseneck to a Fifth Wheel
    The Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter part # BD0289650300 will do a great job switching your current gooseneck over to a fifth wheel. It has an outer tube diameter of 4" and will slide right into your current 4" square outer tube. To verify this ensure your outer tube measures 4" inside to inside. The Gooseneck to 5th Wheel Trailer Coupler Adapter part # KPG5-Q25-IP is also a good replacement that will accomplish your goal. It is a more cost effective option. Between...
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