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maverick_935

freightliner hitch plate

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can find any topics on this.  at this time I plan on using the commercial plate on the truck.  is this a good idea?  was thinking on putting on an air ride hitch on trailer to help with bounce.  any thoughts on hitch.  ok to keep or replace.  thanks

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Having side to side articulation on a 5th wheel hitch is important for an RV.  You can get away with a commercial 5th wheel hitch, but you need to be careful when turning into driveways with dips and other off level situations.  It can put a lot of stress on the 5th wheel pin box and frame without that articulation..

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This is a topic that has been debated to death on this board.

Weather you use the commercial plate or not is your decision.  Keep in mind the pitfalls of it's use:

  1. There is no lateral articulation - It will cause damaging flex of your camper's weak forward frame.
  2. The harshness of the truck's ride will rattle everything loose inside your trailer.  An air inbox will help this to a point.
  3. A commercial plate is just that "commercial".  It makes you look like a commercial truck.  It may draw unwanted attention by DOT officials.

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I actually saw a rig on a site that wasn't that level, the tension of the pin from the lateral twist between the tractor and the trailer. would not allow the pin to pull out of the pocket. 

A commercial trailer frame may handle that twist torsion but an RV frame will crack.

The is why using an air pin with a commercial hitch is not the same as a RV air hitch.  Not a place to save money.  Using an air pin with an RV hitch makes more sense but then the savings are not there.

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Fully grown fifth wheels (aka “hitch” in rv land) have bolsters spaced approx 34” apart to match truck frames. This width plus the lack of occillation others have mentioned is what can place excessive twisting forces on the trailer king pin. A rv sized 5th wheel - hitch plate - Binckley head - is much narrower which makes it’s leverage on the trailer a lot less. Adding lateral movement adds more flexibility and stress relief to the trailer.

This writer does not unnerstan why a side to side oscillating  pin is not built into the trailer pin box. That combined with the hinge crossways of the 5th wheel - hitch - plate on the truck would form a nice universal joint giving flexibility in all directions.

see most any belly dump gravel semi trailer....

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5 hours ago, noteven said:

This writer does not unnerstand why a side to side oscillating  pin is not built into the trailer pin box. That combined with the hinge cross-ways of the 5th wheel - hitch - plate on the truck would form a nice universal joint giving flexibility in all directions.

The short answer:  MONEY and LIABILITY.

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I’m towing with a 1992 FLD 120, factory singled with air ride rear suspension. It’s towed fifth wheel RV’s exclusively since 2000, three different trailers and well over 100,000 miles with zero issues. No visible damage, nothing flying out of cabinets. No issues. We upgraded the trailer 2 months ago and I did have an air ride pin box installed, because the dealer offered to it at cost. But the previous trailers had rigid pinbox’s. 

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Using the factory hitch would more likely show the truck as commercial, BUT with a 5th wheel hitch, it will clearly show it as an RV toter.  Should more readily support its NON-commercial use, at least from my point of thinking.

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An average (please note the word average) commercial fifth wheel is designed for a 55,000 lbs pin weight and 150,000 lbs pull weight. A semi trailer is designed to flex and twist from side to side.  Its all part of the design including the hump in the center.  At average 78,500 lbs loaded truck weight, the truck flexes also and everything works together. 

A quality built RV hitch is designed for a 8,000 lbs pin weight and a max of 32,000 lbs pull weight and is also designed to pivot from side to side along with front to back because the usage models are completely different.

Now take that same truck and attached it to an RV with much lighter loads, lighter trailer tires and different frame structure, you change everything.  Now the weight of the commercial king pin is not there anymore so the tractor does not flex, the tires designed for 80K loads are stiff and so the RV has to absorb the flex.  On a multi-pivot head, that takes the forces.  Installing a multi-pivot commercial hitch does not work either, because the pivot springs are designed for high weights.  An air ride pin box for an RV does not pivot side to side, so that force is still not dealt with, it just adsorbs the up and down jolts .

Now depending on how the RV frame was made, where the steel came from (not all steel is the same), how it was welded together, how it was designed, how it was braced for torsional forces and much much more, some may work on a commercial hitch and many will not.  It also depends on your driving, locations, roads and much much more if that RV is going to survive.  Just because it has worked for one person does not mean is will work for another.

At the end of the day, decision and responsibility is that of the owner.  Yes I could slide my commercial fifth back far enough to hookup to my RV and head out,  I will not because I understand that could happen and just not worth it.  Same reason why I do not hookup a commercial flatbed to my RV hitch,  I could, pin is the same size, but I understand the weight differences and forces at play and just not worth it.

Hope that helps.

 

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6 hours ago, Pug said:

An average (please note the word average) commercial fifth wheel is designed for a 55,000 lbs pin weight and 150,000 lbs pull weight. A semi trailer is designed to flex and twist from side to side.  Its all part of the design including the hump in the center.  At average 78,500 lbs loaded truck weight, the truck flexes also and everything works together. 

A quality built RV hitch is designed for a 8,000 lbs pin weight and a max of 32,000 lbs pull weight and is also designed to pivot from side to side along with front to back because the usage models are completely different.

Now take that same truck and attached it to an RV with much lighter loads, lighter trailer tires and different frame structure, you change everything.  Now the weight of the commercial king pin is not there anymore so the tractor does not flex, the tires designed for 80K loads are stiff and so the RV has to absorb the flex.  On a multi-pivot head, that takes the forces.  Installing a multi-pivot commercial hitch does not work either, because the pivot springs are designed for high weights.  An air ride pin box for an RV does not pivot side to side, so that force is still not dealt with, it just adsorbs the up and down jolts .

Now depending on how the RV frame was made, where the steel came from (not all steel is the same), how it was welded together, how it was designed, how it was braced for torsional forces and much much more, some may work on a commercial hitch and many will not.  It also depends on your driving, locations, roads and much much more if that RV is going to survive.  Just because it has worked for one person does not mean is will work for another.

At the end of the day, decision and responsibility is that of the owner.  Yes I could slide my commercial fifth back far enough to hookup to my RV and head out,  I will not because I understand that could happen and just not worth it.  Same reason why I do not hookup a commercial flatbed to my RV hitch,  I could, pin is the same size, but I understand the weight differences and forces at play and just not worth it.

Hope that helps.

 

Excellent description.  Very nice right up.

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This is what I did.

Slide the angle brackets that held the commercial 5th wheel back as far as you can. You will be able to use some of the factory holes but you will have to drill some. Them bolt a plate to that. Bolt your new hitch to the plate. I do ride 3 inches high in the nose but that has not been an issue so far. Actually when I pull in a park all I have to do is dump my air and I am level. Run the jacks down for stability and leave it hooked up.

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I imagine that IF being nose high is an issue, that the plate you attached to the frame, could have also been attached to some 2"-3" channel bolted to the UNDER side of the frame and then the plate to the channel, or welded together, then the hitch bolted to the plate, which would leave the hitch lower as needed.  I think I have seen this configuration often.

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plate on frame rails done.  rails installed   about to install a new 25k curt hitch.  what height should the head be at for my fifth,   my 1 ton seems high in number but I want the trailer level or a little nose up

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  On 5/14/2018 at 8:29 AM, noteven said:

This writer does not unnerstand why a side to side oscillating  pin is not built into the trailer pin box. That combined with the hinge cross-ways of the 5th wheel - hitch - plate on the truck would form a nice universal joint giving flexibility in all directions.

If the trailer has a side to side oscillation in the pin box, when the truck turns at something close to a 90 degree angle, you get a wierd floppy sensation. The belly dump an a semi, you will feel it and say oh whatever...  A 3/4 ton with a big 5er will have a totally different feeling.

I've run a frameless dump on a truck with no pivot lock on the 5th wheel. I can tell you two pivot points in the same plane makes some interesting bumps in the night.

Edited by Moresmoke

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Ya it would bump once you got the two pins to line up...

RV gadget opportunity alert! We could design a computer board controlled lockout with on screen display / event recorder in the cab...

I am also working on a detachable neck “5th wheel” rv  trailer as a theft prevention device...

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