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Location Of 5th Wheel Plate on Semi? How Far Back


Cotreker

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Plan A ; Someday I am going to take off the Slide-In camper currently on the deck of the Volvo 670 WB 305".  My question is how far behind the rear tire can I place the 5th wheel hitch?  From the edge of the rear tire to the end of the frame is 5 feet; might be able to sit at the 4 foot mark.  However after sitting in a few bed building classes something tells me this should not be done.

Would like to go this far back in order to have some of my storage box.  Mostly would like to haul a car / Jeep on the deck but not length wise.  If this is a bad idea then I move onto Plan B.  Plan B would be to purchase a bumper pull 30 foot trailer and keep the Semi full length 38'  so overall length around 70 feet.   If I could do the 5th wheel plate that far back the truck would never pull a 45' long trailer due to over length issues.

Thanks for setting me straight.....

 

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  • Volvo 670 / 2006
  • 10-Speed 
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  • 2017 Host Mammoth Slide-In Camper on Deck
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Others will be able to answer this better than me since I have a short wheelbase, short rear overhang truck, but I have seen people go out as far as 6 feet behind the rear axle with a fifth wheel kingpin.  My truck has the 5th wheel kingpin approximately 2.5’ behind the center of my single rear axle.

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4 hours ago, Cotreker said:

Mostly would like to haul a car / Jeep on the deck but not length wise.

This will only happen with a smart car. Full stop. If a smart won't work for your use, you will be lengthwise, no alternative. The pin weight of all your future trailers will need to be considered, as well. Lighter trailers can go back further, within reason. The most distance we've seen is 5', even with a lighter rig. This is due to the trailer wagging the truck, due to the longer lever arm the frame length turns into. Minor changes in road surface get magnified, and larger steering corrections are needed.

 

ETA: Allie & Jim typed faster.

Edited by Darryl&Rita

I have been wrong before, I'll probably be wrong again. 

2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication
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Ours is 5ft behind the single axle. I know there are “some” that will say this is perfectly fine but I would never have it built that way again. With boondocking a lot when grey and black are getting full and fuel tanks are below half it makes a difference on weight on front axle. We’ve learned to work around that but could have been at least 18 inches shorter and had enough room for smart or sxs. 

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I carry a car length wise and extended the frame 5'.  The truck is tandem and handles fine.  The front of the car extends a little over the cab which is 42".  The shorter wheel base is handy in tight situations.  In Colorado we can just declare a truck as a recreational truck without having to make it a MH.

Randy

2001 Volvo VNL 42 Cummins ISX Autoshift

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26 minutes ago, Danfreda1 said:

Ours is 5ft behind the single axle. I know there are “some” that will say this is perfectly fine but I would never have it built that way again. With boondocking a lot when grey and black are getting full and fuel tanks are below half it makes a difference on weight on front axle. We’ve learned to work around that but could have been at least 18 inches shorter and had enough room for smart or sxs. 

Dan I am tandem and guess the unloading of the front axle will not be as big of an issue.  Plus my wb is much longer.

  • Volvo 670 / 2006
  • 10-Speed 
  • ATV's & Sleds
  • 2017 Host Mammoth Slide-In Camper on Deck
  • Jackalopee
  • Build article published here

 

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On 9/30/2022 at 8:28 AM, Cotreker said:

Randy can you send me pictures.  Show ramps getting car 

eIrw7Bgl.jpg

I think this will work.  There are 2 ramps on each side going to the ground.  The first connects to the stationary ramps and continues past the truck bed.  The 2nd connects to and is supported by the first ramp.  Started carrying a Blazer about 15 years ago.  Since then I had a Forester and now the Crosstek.   The bed is heavy and I wanted that for added traction while boondocking.  Both rear axles are also air lockers.  The Teton has a heavy pin weight 6,000 lbs + but the truck handles great.

Edited by Randyretired

Randy

2001 Volvo VNL 42 Cummins ISX Autoshift

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It is all about weight and balance. Our pin is 62" behind the center of our single short rear axle. We have a pretty heavy pin weight around 6000# when the Toyhauler is fully  loaded with a heavy vehicle in the garage and 100 gallons of water in fresh water tanks. We carry a smart car sideways on our bed and we have a pretty heavy bed. We off load about 1500# from our front axle but still have a lot of weight on the front axle that we have not noticed any handling issues but we don't drive it in snow or on ice. 

With our weights noted above we do get slightly over our 20k rear axle capacity at 20500#. I did reduce that some buy changing out some our bed plates to aluminum from steel. 

So a lot depends on your pin weights, truck bed weights and weight of the car you want to carry. There is some spread sheets floating around that you can use to do some planning but it also needs some accurate weights and dimensions of what you are starting out with. 

One drawback we have found is with our long overhang, the rear bumper on the truck will sometimes drag so I am always cautious not to get the truck hung up on the rear bumper where the rear tires have no traction.

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On 9/30/2022 at 4:31 PM, Randyretired said:

https://i.imgur.com/RMSYsdel.jpg

I think this will work.  There are 2 ramps on each side going to the ground.  The first connects to the stationary ramps and continues past the truck bed.  The 2nd connects to and is supported by the first ramp.  Started carrying a Blazer about 15 years ago.  Since then I had a Forester and now the Crosstek.   The bed is heavy and I wanted that for added traction while boondocking.  Both rear axles are also air lockers.  The Teton has a heavy pin weight 6,000 lbs + but the truck handles great.

Your link just shows a bunch of junk posts

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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Its been a stone age or two since I have been on the site however I still do a few weight & balance "what if's" for folks wanting to know where to load items and pin / hitch loads.

Feel free to send me the detailed dimensions (axle locations and hitch /pin locations and fuel tanks and weights) then I can calculate various "what if" load situations.

Email me your data at : Inspirationmike@gmail.com

 

Drive on.........Keep your weight in....balance

 

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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