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slowmover 11-05-2014 10:26 AM

As this thread has to do with OP's later thread on best WD hitch:

Connected with weight distribution:
Yukon front 3160,
rear 5160
TT 9140

Connected without weight distribution:
Yukon front 2840
rear 5440
TT 9180

Yukon front 3720,
rear 3600

[Ron Gratz Chart]

Weighing #1 -- TT attached and Weight Distribution Activated
Let Front Axle Load be "FA1" 3160
Let Rear Axle Load be "RA1" 5160
Let TT Axles Load be "TT1" 9140

Then, while in same position on scales, take
Weighing #2 -- TT attached and Weight Distribution Not Activated (WD bars unloaded, but hanging in place)
Let Front Axle Load be "FA2" 2840
Let Rear Axle Load be "RA2" 5440
Let TT Axles Load be "TT2" 9180

Then, drive off scales and drop TT. Return to scales and take
Weighing #3 -- TV only -- TT Not Attached
Let Front Axle Load be "FA3" 3720
Let Rear Axle Load be "RA3" 3600

From the above values, you can calculate:

TV weight = FA3 + RA3 7320

Gross Combined Weight = (FA1 + RA1 + TT1)
{should also be equal to (FA2 + RA2 + TT2) if scale weights are correct}

17,460 & 17,460

TT Weight = Gross Combined Weight - TV Weight


Tongue Weight = (FA2 + RA2) - (FA3 + RA3)

8280 - 7320 = 960

Load Transferred to TT Axles
when WD System is Activated = TT1 - TT2 40

Something is off somewhere (TW, mainly. 12% of 10,140 is 1215-lbs as example). Were the readings all done at the same time?


pjtaia 11-05-2014 07:08 PM

Slowmover: I don't get your calculation of Tongue Weight equaling TV without Weight Distribution minus TV alone. I get 9,180-7,320=1,860; When I weighed just the trailer sitting on the tongue jack I got 1,720; either one is way different than the 960 you calculated...

I did make all these weights at the same time. I went back again at a later date to verify and several of the first few measurements were the same, so I didn't continue to do them all.

I have since determined that my OEM hitch receiver from GMC is rated at only 1,500 lbs, so I am in the process of purchasing and installing a Curt hitch receiver with 2,400 lb rating. We'll see if it makes any difference...

slowmover 11-05-2014 07:11 PM

Stiffer suspension?
Read through the way the chart is arranged. Cross checks. Did I accidentally change the scale numbers? If not then the TW is as shown.

Is your TW really 19%? 9% doesn't seem right either.

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