Pin box to Gooseneck adaptors

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wrxvette

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I am in the process of purchasing a 1 ton dually to pull my trailer in my sig.  The truck has a gooseneck ball in the bed.  I was wondering if it is recommended to get an adaptor for the trailer or should I put a king pin in the truck instead of the ball?

I was told you can't get the articulation with gooseneck that you get with the king pin.  Which I guess would be bad for the trailer right.

Thanks for the help!!

Zach
 
Agree with utah - the ball of the gooseneck gives maximum articulation.

The drawback to the gooseneck adapter is that it stresses the front frame of the 5W severely and it may not be up to it. The adapter acts as  big lever on the kingpin and frame of the overhang and some (many?) trailers are simply not designed for that type of force.  That does not mean they are weak, but they are engineered for the stresses that a kingpin & fifth wheel hitch produce, not those of a gooseneck. Some trailer manufacturers will void the trailer warranty if they are used. Suggest you check with Keystone about that.

On the plus side, we have a few people here who use gooseneck adapters successfully. Perhaps one of them will reply.
 
Gary, I've heard that response before.  Not being an engineer, I don't understand it. 

By my eye, all the weight of the towed 5w is on the kingpin, which is a rather small point.  What difference can extending that point down a few inches make?

I have seen several 5w trailers  converted to use a gooseneck adapter, all with apparently no issues.

*********

Update

I searched on Google and found this good information on another site.  They also seem to lean to "no".

http://www.thedieselstop.com/forums/f32/can-i-tow-fifth-wheel-trailer-goose-neck-hitch-42029/

 
Adding a gooseneck adapter to a 5th wheel does is the same as putting a cheater bar on a wrench - it multiplies the force applied to whatever is at the end of the lever.

For the trailer, the 5th wheel frame is the "nut".  When the truck pulls or the trailer pushes against the hitch, force is transmitted up the lever and tries to twist the 5th wheel's frame.

With a 5th wheel hitch, there's maybe 1 vertical foot between the hitch plate and the 5th wheel frame.  You have a 1 foot lever to transmit force to the trailer's frame.

Change that to a gooseneck, and the lever gets 2-3 times longer because the hitch point is lowered to the bed of the truck.  That's the same as putting a cheater bar on a wrench - you'll have 2-3 times as much force being applied to the trailer's frame.

Take a close look at the construction of a gooseneck trailer - you'll see gussets and/or diagonal bracing reinforcing the forward part of the frame - both at the gooseneck bar and at the front of the trailer itself - to withstand the strain.  A 5th wheel's frame doesn't have nearly as much reinforcement since it doesn't have to withstand the same amount of force.
 
As Lou says, the torque is multiplied substantially. The gooseneck adapter adds 12"-16" of leverage on the pin, so the torque multiplier is over 2x. The pin area of the frame probably wasn't designed to handle it. Maybe it will, and maybe it won't. I'm not saying it can't be done, but there is a risk and want you to be aware of it.
 
Get a 5th Wheel hitch for your truck.
Here on the ranch we have both 5th Wheel and Gooseneck trailers.  We use the proper hitch on the trucks that pull the trailers as they were designed to do.
 
The Signature series of Reese hitches has a good system that allows the interchange of a gooseneck hitch and the 5th wheel hitch using the same under bed rails.
 
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