COG - I broke a cardinal rule...go easy on me

[Duramaximos]

So...months of research and shopping and the wifey and I recently settle on our first truck camper.

I'm talking about a 2006 Okanagan 106 UDB. The TC is perfect for us with respect to amenities and the quality appears top notch.

Did a bunch of reading and research but after all that, still made the mistake of taking it for granted that this "long box" designed camper would provide a center of gravity ahead of the front axle of our 2012 Silverado long box dually...you would think right?

It turns out the centre of gravity point is approximately 2" behind our rear axle. With no turning back on our deal I'm seriously considering selling the camper (which will be hard to swallow at this point) and looking for something more appropriate, unless I can find a glimmer of hope from the forum members here.

On the long highway ride home, we found the camper and truck combo felt a little floaty on some road humps, and a little bit of porpoising (so I've heard it called). I believe some of these things are symptoms of the TC weight being too far back.

So after that lengthy intro, my question is, can the camper be loaded in such a way to make a significant difference to the centre of gravity?

I do believe the fresh water tank is forward of the axle, and the fridge is forward of the axle. However, grey and black tanks are aft, and the 2 30# propane tanks are aft. Currently the TC is empty with the exception of the propane tanks which are full.

Now to make the challenging question even moreso, we intend to tow a 20' Thunderjet boat attached to an 18" hitch extension - I know, I don't ask for much 🙂 I suspect the tongue weight on the boat trailer will be about 500#

If it matters any, the truck is a diesel so it's not exactly a light weight on the front axle.

Thanks in advance for all your suggestions!
Don't be afraid to pull any punches...like I said we're prepared to sell the new camper if we can't find an appropriate solution.

Thanks.

[noteven]

Hi Duramaximos - you will be fine with the COG especially once you put on water and provisons and stuff.

Sounds like a nice camper.

The bit of floaty-ness is the dually's extra stability at work. Nothing to worry about.

[Duramaximos]

mkirsch wrote:
Please stop talking nonsense. Okanagan absolutely did not design this camper to be "incompatible." You don't need to sell your camper!

2" behind the axle is NOTHING. Your owner's manual will specify a wide range of COG locations over the axle. I've seen anywhere from an 18" range, to "anywhere in the truck bed."

Incompatible was the wrong word in retrospect. Not ideal. Assuming our goal is to have the COG ahead of the rear axle.

Thanks again everyone. We're excited again about our purchase and can't wait to get the rig out camping and fishing!

For interest sake I'll post the weights after my visit to the scales.

Cheers.

[trail-explorer]

Golden_HVAC wrote:
You have a Dually longbed . . . .

What are you worried about? They are designed to carry a lot of weight over the rear axle. Sure you are taking some weight off the front axle by the center of gravity behind the rear axle, but look at it with the math in mind.

Dually Long bed, Load it up and go camping and don't worry about it.

Put some Torklift Stableloads on the rear suspension to enagage the overloads, which will slightly stiffen up the rear and reduce the floatiness.

[mkirsch]

Please stop talking nonsense. Okanagan absolutely did not design this camper to be "incompatible." You don't need to sell your camper!

2" behind the axle is NOTHING. Your owner's manual will specify a wide range of COG locations over the axle. I've seen anywhere from an 18" range, to "anywhere in the truck bed."

[BradW]

Don't know, but I assume they allow for some front to rear movement of the trailer relative to the hitch ball so the surge brake master cylinder can be articulated. All the ones on the link I posted say they are surge brake compatable. I sugest you try googling that and I'm sure you will find the answer. Google knows all.

[Duramaximos]

BradW wrote:
Just have to get a surge brake compatible wd hitch. Like these.

What is it about those hitches that make them compatible with surge brakes? I have access to a WDH for free! Want to confirm if it will work with my surge brakes.

[Duramaximos]

Hi everyone,
I have a little more info to share.

First here are the capacities of the truck:

GVWR 13000
GAWR Frt 5600
GAWR Rear 9375

Tires:
Michelin LTX MS2 235/85r17E
3169# per tire at 80 psi.

The wheels are factory aluminum and I don't know how to find their weight rating. Any suggestions?

Camper dry weight is rated as 3200# as equipped.

Next step for me is to fill the fresh water tank and take it to the scales.

Any other suggestions are much appreciated.

[Duramaximos]

Hi everyone.
First I want to say thanks for all the great info so quickly.

I am following the sticker on the side of the camper indicating COG. I have not confirmed its accuracy at the scales but I intend to.

I measured the location of the label from the front wall and it measures 55". I agree with one poster that Okanagan designed this camper to be incompatible with most long box trucks as strange as that is.

I'm optimistic about several suggestions made here so I won't be too hasty to sell the camper.

I'll report again later with answers to some other questions.

Thanks again!

[BradW]

Just have to get a surge brake compatible wd hitch. Like these.

[billtex]

The COG "over the axle" is a somewhat relative term. If you look at the "camper loading" section of your truck manual it shows a range centered around the axle.
COG in front of the axle would be best.
COG on the axle would be fine.
COG slightly behind the axle is still acceptable...

The camper is made to fit a long bed truck...you are not the first...you should be fine.

In any case...you need to verify the axle load and tire/wheel capacity.

Bill

[cleary]

jimh425 wrote:

cleary wrote:

jimh425 wrote:
How did you calculate the COG to figure exactly where it is and are you sure you measured right?

Jim, it is marked on the side of the camper on my 106UDB

Chuck

My point is that something isn't adding up or OP's camper manufacturer intentionally created a camper than can't be used on a truck. That's why I'm doublechecking insteading of assuming the OP knows what they are doing.

They mentioned this is their "first" camper, so I thought it was reasonable that they might be using the numbers incorrectly.

Hey Jim,

The CG sticker on my rig is close to being right over the axle. I've never really checked it out. The 106 is 10' 10" long so has 8 inches less overhang than the 11' 6" rigs a lot of members have. I don't think he has a problem. Like you say he's new to campers. He is probably just going by sticker on it.

Hopefully he'll make another post and fill in the blanks.

Cheers,

Chuck

[mkirsch]

2" behind is NOTHING.

Even if your camper weighed 5000lbs, the effect is equivalent to a trailer with a 210lb tongue weight, as far as weight removed from the front wheels.

The day you can't tow a trailer with a 210lb tongue weight with a dually without a WD hitch is the day I eat my dually.

Your floaty feeling may just be suspension. With 5000lbs in the bed the truck will ride more like a Rolls Royce than a dually.

[Bedlam]

I guess there are options for surge brake equipped trailers. I assumed the friction on the trunnions would decrease braking performance, slow reaction time and delay brake release on acceleration after coming to a stop. My experience has only been with the chain hung bars for the last nine years, so I'm willing to learn...

[jimh406]

cleary wrote:

jimh425 wrote:
How did you calculate the COG to figure exactly where it is and are you sure you measured right?

Jim, it is marked on the side of the camper on my 106UDB

Chuck

My point is that something isn't adding up or OP's camper manufacturer intentionally created a camper than can't be used on a truck. That's why I'm doublechecking insteading of assuming the OP knows what they are doing.

They mentioned this is their "first" camper, so I thought it was reasonable that they might be using the numbers incorrectly.