Cab over clearance

[Jonstoy]

Hey guys I have a few questions for you all. I just recently purchase a new to me 2006 Okanagan 811SL truck camper. Which just happens to be the very first truck camper I've ever owned, so you can say that I'm fairly green with the camper. My question is that when I have the camper in my truck and it's tied down ( I use torklift frame mounted tie downs and their XL spring loaded turnbuckles). The bottom side of the over hang is only about 3/4" from my clearance lights on the roof of my truck. So when I hit a good size bump I've noticed that the overhang will hit the cab lights and make some noise which is a little unsettling. Do you guys have any suggestions as to what's going on?

For some more info my truck is a 2010 F350 super duty 4 door long box diesel. I also forgot to mention that the truck camper already sits on 2 sheets of 3/4" plywood that I've guled and screwed together and notched out so that I can keep my 5th wheel hitch rails installed in the box of the truck. I have a goose neck dump trailer that I tow for business.

So should i increase the height in the bed by adding 2x4 under the plywood? Or am I not tighting down the camper properly? Thanks for any help.

 

[IdaSHO]

Id certainly advise you to increase the clearance between cab and camper.

Generally, I like to see no less than 3 inches.


But it really comes down to the truck, the camper, and how it all works together.

The bed is hard mounted, the cab is on large bushings, and the chassis flexes.

Just how much movement you get will dictate just how much clearance you need.


Id stuff a front corner into a hill side and flex the truck out as far as you can without abusing the truck.

The flexing will give you a good idea of how much clearance you need.

 

[underdrive]

You need more clearance, plain and simple. Drop some 2x6 or 2x8 boards under the plywood (2x4 is kinda narrow and will not spread the load from your camper very evenly on the bed floor) and then do what IdaSHO suggested and see if that was enough or you need even more clearance and thus extra height. You can use a jack under the front axle near the inner "C" to simulate climbing up a bank if you don't wanna leave your driveway while doing the test.

What you're experiencing is caused by the frame bending approximately between the cab and the bed. It's not much deflection, but with the lengths of your cab and camper overhang it's plenty enough to make the two collide. If you had a regular cab the effect would not be so noticeable, but even then you'd surely need more than 3/4" clearance.

 

[boxcar1]

You can use lumber or you can use 1-2" thick sheet of ridged foam insulation.
This works very well and is light enough as not to be such a pain to install every time you load the camper.
I have a good friend that I travel with who has been carrying a 10' Bigfoot on an 06 super duty this way for many miles .

 

[Hutchcab]

I had the same issue putting my new to me '93 Lance on my '01 F250. I only needed ~3" height but used 2 sheets of 4x8x2" blue foam insulation from Lowes. Plenty of space now.

 

[Jonstoy]

Hey those are all great ideas guys. I'm going to be increasing the height under the plywood with some lumber screwed to the under side. Hopefully that will make all the difference for me. I do really like the idea of the rigid foam simply because it's such a light weight addition. Will the foam really be up to the task of handling all that weight?

 

[boxcar1]

Yes it is. The load is spread out over the entire surface of the foam .

 

[dfrank]

When shimming with just foam, do you think that is adding too much flex?

I ran a 4x8 x 2" sheet of pink board under my lance this winter both for clearance and warmer floor.

Seemed it swayed a bit, but It was on a truck it had not been on before with different tie downs, so I really wasn't sure if it came from the foam.

After driving like that all winter, I was impressed with how little squish damage had been done to the foam.

If this isn't adding to the vibrating cabover, I'd like to keep it.

 

[IdaSHO]

As long as it is XPS foam, you should be fine.

The lighter duty of the XPS should be rated at a compression strength of 15PSI



Assuming your pickup is a long bed, and are using a full sheet...

4'x8' = 32 square feet. 12"x12"= 144 square inches per sq ft


32 x 144 = 4608 total square inches per sheet

4608 x 15 (PSI rating) = 69,120 lbs per 4'x8' sheet of compression strength.


If you dont think that is sufficient, there is also a 25, 30, 40, 60 and 100 PSI rated XPS as well. :coffeedrink:


And if I goofed up on the math anywhere, please let me know :sombrero:

 

[Jonstoy]

That foam seems pretty soild to me and the math looks correct as well. For all of you fine gentlemen that helped me out, what I ended up doing was screwing 9 pieces of 2x6 under the plywood for added height. I haven't had the camper in the truck just yet but on Friday I'll be loading it up to go camping for 3 days. I'm excited to see if this will end up fixing my clearance issue. So with some rough math I should have about 2 1/4" of clearance between the overhang and the cab lights. Fingers crossed this will help. If not I guess I'll be buying some rigid foam from lowes or Home Depot.

 

[gtbensley]

I use ridged foam on my camper to bump it up two inches for clearance. Works great and has no sway.

 

[boxcar1]

Your math looks good. I doubt that the foam would add any sway. Pretty sure it was the new truck.

 

[dfrank]

Cool. The 2" foam stays.

anyone got a line on some black foam? I'd like to put thinner foam on the bottom of the part over the bed rails, to insulate and close up the gaps.

Blue, pink and white are not that visually pleasing, and the '89 Lance needs all the help it can get keeping up appearances with the '05 Ram dually we just got to carry it!

 

[boxcar1]

The foam can be painted any color you want.

 

[bumblebus]

I'm thinking of removing the 2x4 wood height extender I built under my slide in and replacing with 2" rigid foam. I, unfortunately, have a hard plastic bed liner and I'm worried about how slippery the foam will be. Suggestions on how to keep it all from slipping on that stupid bed liner (besides 'remove bed liner' haha)? Maybe a rubber mat also? Thx for tips. Haven't mounted camper ever so looking to do it right the first time in case it stays on all summer haha.