Originally Posted by Johnnyb5646
My cat scale passes were one empty one with trailer. And the 1400 arrived from scale weight at each pass.
Tongue weight = GVW with trailer but with the spring bars of your WD hitch disconnected, minus GVW without trailer but with the shank/head/ball mount of the WD hitch in the receiver. You cannot determine tongue weight based on just rear axle weights, or with the spring bars of the WD hitch tightened, or with the shank/head/ball mount removed from the receiver. GVW = weight on both axles of the tow vehicle.
Hitch weight is a bit higher than tongue weight because of the weight of the WD hitch. So for total hitch weight, proceed as above except remove the head/ball mount from the receiver before you weigh the truck without trailer.
Tongue weight determined by two passes over the scale should give you within 50 pounds of the tongue weight shown by the Sherline tongue weight scale. They probably won't be exactly the same because of rounding of the weights on the CAT scale pads. For example, when fine-tuning my WD hitch, one pass over the CAT scale gave me GCW of 10,400 and a second pass gave me GCW of 10,420. The GCW weights should have been identical, but that 20 pounds difference was because of rounding of the different weights on the 3 pads pf the CAT scale and two passes over the scale.