mojoroo wrote:
How does it look?
First, let's look at the Gross Vehicle Weights.
The GVW for the truck is 3620+2820 = 6440#.
The GVW for the trailer is 1380+7200 = 8580#.
The GCW for truck plus trailer is 6440+8580 = 15020#.
This brings us to the first weight discrepancy --
the GCWs measured for the TV+TT with and without WD applied are 14900# and 14900#.
There's a difference of 120# between the GCW for TV and TT measured separately and for TV and TT on the scales at the same time.
Since the "truck only" axle loads are identical to the loads which you reported in the other thread on 6/1, I need to ask --
did you re-weigh the truck alone today or are you using the weights which were obtained yesterday?
If you are using the weights from yesterday, the weight today probably is 120# less, and that will affect the interpretation of the data.
For example, using today's numbers shows the front axle load decreased by 620# when TW was applied with no WD.
If the tongue weight really is around 1380#, the load removed from the front axle would have been closer to 500#.
If the "truck only" front axle load is reduced to 3500#, the CGW discrepancy will be eliminated, the load removed from the front axle will be a more realistic 500#, and the tongue weight estimated from TV+TT with no WD minus truck alone is 7620-6320 = 1300# which is closer to the 1380# measured with the tongue jack on the second pad.
Regarding "tongue weight" -- the load measured with the tongue jack on a scale pad is not the same as the load imposed on the ball by the coupler.
The difference in load is due to the difference in distance from TT axles to center of tongue jack versus the distance from TT axles to center ball coupler socket.
For the Northtrail 30USBH, the load measured under the tongue jack will be about 4% greater than the load measured under the ball coupler.
IOW, the actual tongue weight for your loaded TT was about 0.96*1380 = about 1320#.
Assuming the correct "truck only" front axle load was 3500#, TW removed 500# from the front axle and application of WD caused 320# to be restored to the front.
That's a Front Axle Load Restoration of 320/500 = 64%.
For your 2004 2500HD, Chevrolet specifies a FALR of 100%. IOW, the front axle load should be returned to the unhitched value.
Today, Chevrolet says that weight distribution is "optional" for the 2500 HD.
It's up to you to decide how much load distribution you want for your truck.
Ron