Weight Calculations

JIMNLIN wrote:
I've loaded several hundred GN/pintle hitch flatdeck and stock trailers and was always surprised how small the percentage was of adding a load on the azz end of the trailer and changes hitch weight.
First off the center of the axles doesn't work like a teeter totter #1 because one end sits on the trucks hitch. #2 can be distance behind the last axle spring hanger and #3 is the distance from the hitch to the first axle spring hanger. Without seeing the trailer I wouldn't guess a weight.

Loading a 21000 lb 38' GN tri axle stock trailer with young stuff....cows...and big mature bulls is a guessing game. I know adding the 2200 lb bull in the last stall didn't change the weight on the ball by a quarter of a inch = approx 200+ lbs.

Adding 300 lbs on the rear bumper of a small TT IMO can make a ill handling combo.

Assuming you keep the trailer reasonably close to level, the weights do transfer like a teeter totter:

#1 The teeter totter is purposely out of balance with the front end longer than the back end. This would be like putting a 10ft arm on one side and a 5ft arm on the other end...to keep the teeter totter level, you would need a lifting force (ie: hitch weight) under the rider on the long end.
#2 & #3 Unless The trailer is wildly out of level, this won't have an impact as the springs will give pretty closely approximating a central pivot point.

Gooseneck & 5th Wheel trailers have a different geometry from bumper pulls as they are shooting for 20-50% of the weight on the hitch (semis are typically around 50%). This means the trailer wheels are set much further back typically. As a result, the moment created by a weight put way at the back has far less impact on the pin weight.
- Bumper pulls travel trailers tend to have the wheels centered 55-60% of the length back from the hitch. So weight placed a few feet behind the rear bumper will tend to remove 80-100% of that weight from the hitch.
- 5th Wheels tend to be 65-75% back from the hitch. This will result in a similar weight removing 30-60% of the weight from the hitch. Add in that the hitch weight is much higher to begin with and you can absorb more weight without significant impact on the handling. On a lot of commercial GN trailers, the trailer axles may be 80-90% back and it may only remove 5-20% off the hitch (hence your 2000lb bull example)