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gbsteph's avatar
gbsteph
Explorer
Oct 12, 2020

Truck Camper Weight...I know, I know

On our last camping trip, I weighed my new since this January, 2019 Ram 3500 CTD DRW 4WD with a 2020 Host Cascade on it's back. Had an average load of gear and supplies. Full fuel, 75% full propane, empty waste tanks and about 10 gallons of fresh water. GVWR is 14000, I was at 14480. Front GAWR is 6000, I was at 5180. Rear GAWR is 9750, I was at 9300. Over on max vehicle weight but under on axle weight, so I am comfortable with that. My 04 Ram 2500 with my old Lance 815 had similar numbers. Over on GVWR but under on axles. I'm not worried about the numbers, but my question is, does anyone know of a formula for calculating removed or added weight to a known vehicle weight based on distance from the CG. I've searched the web but only find stuff on aircraft, which I guess would work. If anyone has a simplified calculation, I would love to hear it.

Thanks
Greg
Truck Campers

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  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Oct 13, 2020
    GVWR is taxable number given by lawyers.
    But Axle rating is number given by engineers and that is what I am worry about.
    It is common that heavy axles are used on several levels of truck categories, but just becouse the same model of axle is rated 15k lb in F450 and 10k in F250 doesn't have to mean you can put 15k on F250 bed.
    You don't know if the axle derating is just legal issue, or smaller bearings and smaller shafts.
    Most likely it will be different gears anyway
  • jimh406's avatar
    jimh406
    Explorer III
    Oct 13, 2020
    jdc1 wrote:
    He hasn't even put people in and he's overloaded.


    Maybe, but also his axle could be a couple of thousand pounds higher. For sure, the tires would be rated higher than 9000 with 4 of them.

    I think all of the pickup bed DRWs have artificially low GVWR.
  • StirCrazy's avatar
    StirCrazy
    Moderator
    Oct 13, 2020
    jdc1 wrote:
    He hasn't even put people in and he's overloaded.


    I dont think he is overloaded at all. still lots of room on the front axel and some on thre rear. GVRW is a useless number its the axes and tires that matter.

    Steve
  • jdc1's avatar
    jdc1
    Explorer II
    Oct 13, 2020
    He hasn't even put people in and he's overloaded.
  • noteven's avatar
    noteven
    Explorer III
    Oct 13, 2020
    Weight distribution between the axles is point loads on a beam math.

    Behind the rear or ahead of the steer axle is lever math ^ what Kayteg1 said. ^

    I'm 80% numbskull and the other half is number dyslexic so I used to use a pen and paper and tape measure and the calculator on my phone to get a visual picture like when laying out weight distribution on commercial trucks.
  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Oct 12, 2020
    I think all 5th Gen duallys are 12"rear pumpkin. But even if it was the 11.8 or 11.5, the 11.5 is rated at 10klbs so no worries, keep on truckin!
  • jimh406's avatar
    jimh406
    Explorer III
    Oct 12, 2020
    The actual axle rating could be higher if you have the 12 inch AAM. I’d check to see if it is a 12 and then find the axle rating. For instance, my F450 has a GAWR of less than the actual Axle rating. Yours could be similar.
  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Oct 12, 2020
    Look up free body diagram for beams. There are online calculators if you do not know how do the calcs manually.
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Oct 12, 2020
    Looks to me that all you need is about 300 lb in your holding tanks to overload rear axle?
    COG is movable point.
    Let's say you have A distance between the axles and you add 300 lb at distance of B behind the rear axle.
    So the multiplier on rear axle is going to be A+B/A
    Or numeric sample, when you have 10 ft between the axles and put 300 lb of waste water 6 ft behind rear axle, the result will be 300x(10+6)/10=480 lb added to rear axle.
    The 180 lb will be taken off front axle by cantilever weight.

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