determining pin weight

RCMAN46 wrote:

ependydad wrote:
Here's how you weigh the rig:
How to Weigh Fifth Wheel Camper

Once you have the 2 weights, here's a calculator that will spit out all of the numbers for you:
Actual Weights - Fifth Wheel CAT Scale Calculator

Easy peasy lemon squeezy. The hardest part is parking the rig out with the trucks. :)

I do not agree with the second calculator.

Using my example from my post on 4/21/14 8:50am I got a tongue weight of 260 lbs and the calculator got 380 lbs. I had also done a bathroom scale weight that same day and got 250 lbs. So I am sure the calculator is wrong.

They took the difference between the truck drive axles which is not correct. If the pin is behind the rear axle or as all TT tongues are there is some weight taken from the steer axle and it shows up on the drive axle.

And if as with many 5th wheels the pin is in front of the rear axle some of the pin weight will show up on the steer axle.

So it's an interesting conundrum and a choice that I specifically made.

In the code, I have:

Code wrote:

If the "Loaded Steer Axle" is greater than the "Unloaded Steer Axle", then calculate pin/tongue weight by:
Pin Weight = "Truck Loaded Weight" - "Truck Unloaded Weight"

Otherwise, then calculate pin/tongue weight by:
Pin Weight = "Loaded Drive Axle" - "Unloaded Drive Axle"

My thinking was, your tongue weight is still there even if it is unloading the front (i.e. it shouldn't be penalized/decreased because of it). BUT- the fact that you verified yours with an actual bathroom scale gives your real world testing to my theoretical thoughts.