I grabbed a quick measurement from our new 5er (2008 Heartland Big Country) and it was 59" from the bottom of the front portion of the body to the ground. That's measurement "D" in this picture.The trailer looked like it was sitting fairly level but I had no way to check that at the time so this measurement could be off. Now I measured from the ground to the top of the side of the bed on my 2015 Ram 3500 and I get 57 1/2", measurement "C". That's only 1-1/2" of clearance between the truck and 5er.The trailer didn't have a pin box on it when I saw it so I don't have measurement "A". It's now got a brand new Rota Flex pin box on it. I just got a Trailer Saver air hitch, but don't have it installed yet so I don't have measurement "B" yet either. How much clearance should I have between C and D to be sure I'm OK on inclines, bumpy roads, etc?

Subtract A from D. Now subtract 6" from the answer. Now place a straight edge (2x4) across top of bed side to side above at top of the hitch 5th wheel. Set top of hitch 5th wheel plate to the final dimension to bottom of straight edge and top of hitch 5th wheel plate. This will give you the 6" needed for bed clearance. B & C are irrelevant.

OK I see what you mean. But is there a minimum that D-C should be?

Well first of all unless you have the Ram air ride, your Ram 3500 will squat some. It seems to me that my 2016 squats a bit more than the old 2001 2500, the 2016 also rides better. You need to find out how much the hitch will move vertically as that will have an effect.That hitch may be a bit of overkill for a 14,000# GVWR , and will eat up a bunch of your zpayload.

BurbMan wrote:OK I see what you mean. But is there a minimum that D-C should be?I believe 6" is considered a minimum. Also consider C for the loaded truck rather than empty.This is the formula shown in your pic to need 6" but add 2" for rear squat of the truck.Roads in general are fine. It is the driveway entrances etc that may come close.

Do your measurements while hooked up with the landing gear retracted. Otherwise, the compression of the rear truck axle and the exact levelness of the trailer can easily throw your calculations off by a few inches.Now you just have to measure from trailer overhang to truck bed rails. (this assumes the trailer is sitting pretty much level and the truck is not squatting an excessive amount)

Bed Rail Clearance? | Good Sam Community

valhalla360
Navigator
Feb 10, 2022
Do your measurements while hooked up with the landing gear retracted. Otherwise, the compression of the rear truck axle and the exact levelness of the trailer can easily throw your calculations off by a few inches.

Now you just have to measure from trailer overhang to truck bed rails. (this assumes the trailer is sitting pretty much level and the truck is not squatting an excessive amount)
time2roll
Nomad
Feb 10, 2022
BurbMan wrote:
OK I see what you mean. But is there a minimum that D-C should be?
I believe 6" is considered a minimum. Also consider C for the loaded truck rather than empty.

This is the formula shown in your pic to need 6" but add 2" for rear squat of the truck.

Roads in general are fine. It is the driveway entrances etc that may come close.
rhagfo
Explorer III
Feb 10, 2022
Well first of all unless you have the Ram air ride, your Ram 3500 will squat some. It seems to me that my 2016 squats a bit more than the old 2001 2500, the 2016 also rides better. You need to find out how much the hitch will move vertically as that will have an effect.
That hitch may be a bit of overkill for a 14,000# GVWR , and will eat up a bunch of your zpayload.
BurbMan
Explorer II
Feb 10, 2022
OK I see what you mean. But is there a minimum that D-C should be?
Cummins12V98
Explorer III
Feb 10, 2022
Subtract A from D. Now subtract 6" from the answer. Now place a straight edge (2x4) across top of bed side to side above at top of the hitch 5th wheel. Set top of hitch 5th wheel plate to the final dimension to bottom of straight edge and top of hitch 5th wheel plate. This will give you the 6" needed for bed clearance. B & C are irrelevant.

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