Forum Discussion

Duramaximos's avatar
Duramaximos
Explorer
Apr 23, 2014

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

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.
Truck Campers
  • sky_free's avatar
    sky_free
    Explorer
    Apr 23, 2014
    I think your truck has a 167.7" wheelbase, so having the COG 2" behind the rear axle will remove 2/167.7 or 1.2% of the weight you are adding from the front axle. If the TC fully loaded weighs 5,000 lbs, that is -60 lbs, or "not much". I think the bigger effect will be from the trailer.
  • Golden_HVAC's avatar
    Golden_HVAC
    Explorer
    Apr 23, 2014
    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.

    Lets say the camper empty weight is 4,000 pounds and your wheelbase is 165". 2" behind the rear axle means that 1/130 of the weight will be taken off the front axle and transferred to the rear axle. So a load of 1300 pounds would move 10 extra pounds toward the rear axle. Your 4,000 pound camper will add 4,030 pounds to the rear axle, and take away 30 pounds from the front axle.

    I used to have a SRW F-350 supercab truck. It was very stable with a large camper on it. I never did take it to a scale, but know that it was heavy, and I had a GVWR of only 9600 pounds. I am somewhat sure that your truck will be well within the front and rear GAWR and overall GVWR. However you will not know until you take it to a scale. Find one of the CAT scales, or find a local moving company and ask if they will let you get the weight there. I took in my motorhome and checked the weights all around, measured the front passenger wheel, then right side, then total weight.

    Also if you have the typical front water tank, the camper might be more stable with water in it, as it will add about 30 gallons or 240 pounds towards the front of the camper.

    Fred.
  • Raften's avatar
    Raften
    Explorer
    Apr 23, 2014
    You are fine. For your peace of mind try to load heavy stuff forward, and keep your waste tanks light when you can. A floaty and porpoising feeling with TC's is just a fact of life. You are pushing a barn door down the road and the faster you go the more you feel it.
  • cleary's avatar
    cleary
    Explorer
    Apr 23, 2014
    Relax buddy, you're just fine. We have 08 106 UDB and our F350 Dually with a 32 inch extension handles it without a problem. We pull a 16 foot trailer loaded with 4-wheelers, or sleds (snowmobiles), gas and a lot of other junk.

    All 3 tanks, fresh water, poop and grey are forward in the basement. If you lift the step into the cab over you will see that the fresh water tank is 7 inches from the front wall of the basement and the grey is about 12 inches from it. If you look into the basement storage from the rear you can see that all 3 tanks are forward. I visited the OK factory before getting our 106 and I have a picture of the basement upside down before the floor was installed. You can see the tanks already installed. I would post it here but for some reason my new computer wont' let me. If you will PM with your email address I will send it to you.

    Wet, with all our gear ready to rock and roll our 106 tips the scales around 5 grand.

    It's a great camper, you'll love it,

    Chuck
  • badboy368's avatar
    badboy368
    Explorer
    Apr 23, 2014
    maybe a set of weight dist. bars on the trailer will help transfer a little weight to the front axle... just a thought :h
  • billtex's avatar
    billtex
    Explorer II
    Apr 23, 2014
    badboy368 wrote:
    maybe a set of weight dist. bars on the trailer will help transfer a little weight to the front axle... just a thought :h


    Yeah...that's what I was thinking...may handle even better when towing if you use a WD hitch.

    In any case, you're fine...as noted it's just the way TC's handle....water in the tank and trying to load weight forward may all help too.

    BTW; nice camper.

    Bill
  • woodhog's avatar
    woodhog
    Explorer
    Apr 23, 2014
    After you do the scale weights if the front axle has spare weight capacity just add a front storage box to the truck.. Fill it with enough junk to move the COG forward. One can always use more storage...

    Don't exceed the tire load index and the axle manufacturers axle ratings.
  • Handbasket's avatar
    Handbasket
    Explorer
    Apr 23, 2014
    If it won't put you beyond weight limits on the front axle, maybe add a winch mount & winch? Or any of several other heavy front end accessories.

    Jim, "Mo' coffee!"
  • CaptPicky's avatar
    CaptPicky
    Explorer
    Apr 23, 2014
    You might change your shocks. I pull a 5th wheel but it had a problem with "porpising". A new set of shocks on the rear made an amazing difference.
  • BradW's avatar
    BradW
    Explorer II
    Apr 23, 2014
    Duramaximos wrote:
    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#

    Add a good WD hitch and all will be good. My rig actually drives better with a 7,500 lb trailer behind it on a Reese WD hitch.

    Brad

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