Axle Weight Limits

If my math is wrong then so be it. But be sure to show your work..

If you scale at 12000, 23000, 21000 and 17000 with the 5th wheel at the rear most position, and then you slide the 5th wheel forward to the most forward position, you should be legal.
Again it all depends on the load size, placement, 5th wheel length, and more.
Physics literally agrees with. Weigh bearing is proportional, if more goes to one side, it has to come from the other. Otherwise 4 axle HH trucks would have fixed 5th wheels and RGNs wouldnt have multiple kingpin locations and long necks.

 

Moving the fifth wheel on the truck does nothing to change the weight pushing down on the fifth wheel from the trailer.

The end.

 

Sliding a FIFTH WHEEL SLIDE moves weight from your DRIVE AXLES to your STEERS and vice versa. It does not change the distance between the KING PIN and your TRAILER AXLES therefore not shifting any weight from your trailer.



I’ll put your full-proof theory to the test tomorrow, though. Just for my own amusement.

 

No sir.
The only way to lessen the weight on the front trailer axle and put more on the rear axle is to shift the load (weight) on the trailer itself.

The entire weight of the load is transferring to the ground through 3 point: kingpin, front trailer axle, rear trailer axle.

The kingpin is fixed on the trailer, so the distance between that and the trailer axles never moves, therefore the weight distribution never changes.

By changing the fifth wheel position you are only changing the location of the truck! What if you removed the truck and put a post under the kingpin down to the ground? How could you ever change the weight on the trailer axles? You couldn't.
If your rear trailer axle was a slider, THAT would change axle loads. Or as I said, shift the product to the rear.
As @stwik said, moving the truck backwards only puts the load closer to the steers.

 

I'd like to see the trailer roll around with 21 and 17 across the scales.

I know 2 that went OOS. The rear air bags weren't inflated.

 

It does however change the distance between your drive axles and your trailer axles. So some weight will move. Not a lot, but some, say 100-200 pounds max.

 

Some weight will move between steer axle and drive axle, no weight will move between front trailer axle and rear trailer axle.. The load on the deck stays in the same place relative to the kingpin. The kingpin is not moving, only the truck is. One has nothing to do with the other.

 

That ONLY happens if the height of the fifth wheel causes the angle of the trailer floor to change. By raising the king pin, a small fraction of the weight is transferred to the tandems (and vice versa).

Distance between the drives and tandems has no effect on weight distribution unless the distance between the kingpin and the tandems changes.