Fifth wheel clearance

[bmurdock]

I am purchasing a 2015 F-550 4X4 with a 84" cab to axle and having an 11'-0" utility service body made for it. The body will be 33" high, the top of the body will be just over 18" above the bed, and the top of the body will be approx. 55" off the ground (the same height of my current F-250 4X4). The body builder advises that when the body is installed on the truck that this dimension should decrease by 1" to 2" as the unit weighs 2200 lbs empty. I am looking at putting approx. 3000 lbs. in it. There will be a 1/2" steel plate mounted between the truck frame the body will be mounted over for attachment of the bed rails of the hitch. I am looking at installing a Husky 26K fifth wheel hitch with an adjustable height from 15 3/4" to 19 1/"4. I chose this hitch because of the height and weight capacity.

Has anyone done this type of build? With this setup, does it look like I will have enough clearance between the top of the body and the fifth wheel trailer. Any other comments, concerns, or recommendations would be greatly appreciated.

[Skip426]

Sounds like a lot of weight, on the rear axle , do you know the pin weight, of the 5er you have in mind, or have any idea , how much capacity on the RAWR, you're going to have left?

[Leland1950]

I have a 550. It has the Dana 135 rear, 13,500lbs but the wgt you're putting on the front has to be taken into account also it just isn't going to all stay on the rear end. You may have a heavier front axle, but mine is pretty close to the max with the trailer and truck loaded.

[bmurdock]

The GAWR 14,702# and the trailer pin weight ~3,500#.

[SmokeyWren]

Originally Posted by bmurdock

With this setup, does it look like I will have enough clearance between the top of the body and the fifth wheel trailer.

Depends on the 5er. Some 5ers are farther from the kingpin to the ground than others. To get an idea, back your F-250 under the level 5er (or an identical model 5er) and measure the clearance. If you have less than 4" clearance, then you will probably have trailer to body contact when crossing a dip as you exit the highway and go into a convenience store or some Wal-Mart parking lot. That 4" clearance should increase to about 6" clearance when you put the 3,500# pin weight on the F-550 suspension while keeping the trailer level front to rear.

I towed a 5er with my F-250 that had only 5" clearance between the underside of the 5er and the top of the bed at the tailgate when hooked up. And I had dings in the top of the bedrails where there was contact on crossing dips and gullies and barrow ditches as I exited the highway at an angle to the dip.

If the trailer has ordinary leaf spring suspension with the spring perches mounted under the trailer axle, then you can move those spring perches to the top of the axles and gain 3" to 4" additional clearance. That's called "flipping the axles" on the trailer, but the axles are not literally turned over - the springs are moved from under the axle to over the axle.

Any other comments, concerns, or recommendations would be greatly appreciated.

Probably too late for your use, but Knapheid makes a Westerner Storage body that's a service body but only 28" high. They come in a max of 60" cab-to-axle (CA) length, but your body builder could probably copy that design to fit your 84" CA.
Westerner Storage Bodies Product Gallery | Knapheide

For years I've thought that Westerner Storage body was even better for RV trailer towing than the more expensive tow bodies such as Western Hauler.