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stro1965's avatar
stro1965
Explorer
Jun 09, 2014

Help me make sense of the scale numbers

Since switching from a 2012 F250 to a 2014 Ram 3500, I've got a "pin high" issue that is concerning. When on the truck, the pin is a full 7" higher than it is when off the truck and level. Fearing this might be overloading the rear axle on my 5er, I hit the scales this morning for the first time.

Truck alone:

Steer axle: 5080
Drive axle: 3380

Truck with 5er:

Steer axle: 4820
Drive axle: 6080
Trailer: 9340
(2700 pound pin weight was about 500 more than I expected...affirms my decision to go with the 1 ton truck)

Splitting the 2 7K trailer axles on the scales:

Front: 4200
Rear: 5260
(While the rear axle is carrying 1060 pounds more than the front, it still below it's 7K rating)
I also did an experiment to see how much more weight is on the drive axle when towing the trailer with the slider hitch in the rear position:

Steer axle: 4820
Drive axle: 6120 (only 40 more pounds?? Really??)
Trailer: 9360

So, the whole point to all of this is to ask your opinions on the weight difference between the front and rear trailer axles. Is 1060 pounds simply too much difference even though I'm under the axle ratings? Maybe I can live with the goofy pin high look if it's not really an issue?

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  • stro1965's avatar
    stro1965
    Explorer
    Jun 09, 2014
    RCMAN46 wrote:
    True pin weight is the difference of total truck weight with and without trailer attached. In the OP's case his hitch must be behind the centerline of the rear axle which results in unloading of the front axle.

    Truck only is 5080 + 3380=8460

    Truck with trailer is 4820+6080=10900

    Thus the true pin is the difference of 2440.


    Ahhh, I see, thank you. I can't figure out how it unloaded the steer axle, as the hitch IS a couple of inches forward of the trucks drive axle.
  • RCMAN46's avatar
    RCMAN46
    Explorer
    Jun 09, 2014
    True pin weight is the difference of total truck weight with and without trailer attached. In the OP's case his hitch must be behind the centerline of the rear axle which results in unloading of the front axle.

    Truck only is 5080 + 3380=8460

    Truck with trailer is 4820+6080=10900

    Thus the true pin is the difference of 2440.
  • stro1965's avatar
    stro1965
    Explorer
    Jun 09, 2014
    hmknightnc wrote:
    How much bed to FW clearance do you have? I'd be adjusting my hitch clearance down to around 4 inches if you got more than that to reduce that 7" unlevel condition.

    Also something is not right with your weight measurements. Attaching the FW should add slightly to the front axle weight not unload it like your measurements indicate. Is the center point of your FW hitch forward of the rear axle, it should be.


    I only have about 5 or 6 inches bed clearance now, not much wiggle room at the hitch. Hitch is mounted forward of the truck axle. I was surprised at that too, but that's what the weigh sheets say.
  • NC_Hauler's avatar
    NC_Hauler
    Explorer
    Jun 09, 2014
    RCMAN46 wrote:
    I calculate your pin at 2440.

    What is the weight rating of the trailer tires?


    Pin weight is considered the amount of weight that is put onto the hitch, which is what the OP stated...2700#...difference between 6080 (with 5er pin weight setting on hitch over the rear axle), less empty weight of 3380, difference is 2700#

    Sounds like OPs 5er is riding "nose high", putting more weight on the rear axle of his 5er....I would lower the 5er some as one stated and try to transfer some of the rear axle weight onto the 5er's front axle.
  • stro1965's avatar
    stro1965
    Explorer
    Jun 09, 2014
    RCMAN46 wrote:
    I calculate your pin at 2440.

    What is the weight rating of the trailer tires?


    How did you get 2440? I just took the difference in the drive axle with and without the trailer...is that wrong?

    I've never looked at the rating on the trailer tires, guess that would be good to know!
  • roy67ss's avatar
    roy67ss
    Explorer
    Jun 09, 2014
    The pin weight, as shown, would be 2700-2740lbs. Was it windy or something that day? The total weight on the truck and the truck should not change no matter where the hitch is. The distribution on the trucks axles is all that should change. I think your first front axle weight is not right. You will likely experience tire problems on the trailer rear axle with that much difference between the axles. Are you running G rated tires on the trailer? If only E rated tires you are limited to 6080lbs per axle, even if they are 7000lb axles. The 7000lb axles probably only got you better brakes and no weight increase unless G rated tires are part of the option.
  • RCMAN46's avatar
    RCMAN46
    Explorer
    Jun 09, 2014
    I calculate your pin at 2440.

    What is the weight rating of the trailer tires?
  • hmknightnc's avatar
    hmknightnc
    Explorer
    Jun 09, 2014
    How much bed to FW clearance do you have? I'd be adjusting my hitch clearance down to around 4 inches if you got more than that to reduce that 7" unlevel condition.

    Also something is not right with your weight measurements. Attaching the FW should add slightly to the front axle weight not unload it like your measurements indicate. Is the center point of your FW hitch forward of the rear axle, it should be.

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