Old-Biscuit wrote:
Allworth wrote:
I think that 20% number started out as an estimated average over all designs and all loading conditions.
Exactly.......
20% is ball-park number
As found in the fine print from truck mfg. towing guides the following percentages are recommended
Trailer tongue (trailer king pin for fifth-wheel towing) load weight should be 10-15% (15-25% for fifth-wheel towing) of total loaded trailer weight.
avvidclif1 wrote:
It's not quite that simple. GVWR of my RV, 15,500lbs X 20% = 3100 lbs, should be max pin weight. Actual weighed pin 3400 and not even close to GVWR. Oops and back to the drawing board.
This is why I actually prefer to extrapolate from dry weights. You can figure out the dry weight percentage, add 2-3% to it, and then multiply that out by a realistic wet weight (or GVWR to be conservative).
In fact, I have a little calculator for it:
http://www.towingplanner.com/Estimators/TonguePinWeightFromDry
