Old-Biscuit wrote:
Take dry pin weight..divide it by dry trailer weight...then multiple that by trailer gross----that will get you close to wet pin weight
Example: 1026# (dry pin) divided by 6910# (dry trailer) equals 0.1484 times 11551# (trailer gross) equals 1714 for wet pin weight.
I prefer using the old 20% rule Trailer gross times 20%
11551# (trailer gross) times 20% equals 2310# wet pin weight
I have found that the 20% rule is closer to actual pin weight vs the above formula (almost a 600# difference in this example) 600# difference in pin weight can be alot.
This is exactly what I'm doing with my online calculator. You plug in the dry #s from the specs and it figures out the percentage. I offer a place to increase that from 0.5% - 1.5% (because that's the variance I have seen in my camper).
The problem is exactly what you described - I had one person test it and compare it against his actual scaled results. His dry percentage is 18% but his wet percentage is almost 23% - in his case, it was a 600-800 pound difference that not only put him over GVWR, but also RAWR and even a touch over tire load capacity.
Even weirder, I had someone else test it and they've described an eight percent LOSS of actual pin weight percentage from dry to (repeated) scaled weights. His wet pin weight is actually lower than the advertised dry pin weight.
I was hoping to be able to provide a tool that went above and beyond the standard, "estimate for 20%-25% with exceptional cases as low as 15%". But, at this point- I think it is proving to be a fruitless venture.
