Originally Posted by nilesrob
Totally get the headache thing. Here are my results. Any thoughts appreciated!
The trailer tows great, although the tail end of my TV seems to hang a little low when hooked up...
Good job on acquiring scale tickets.
The FA is the crucial first step in establishing a proper baseline.
FA, solo: 5,040-lbs
This is what we also
want with the trailer hitched and WD activated.
Trailer hitched, no WD: 4,560-lbs (480-lbs removed)
Trailer hitched, WD active: 4,760-lbs (280-lbs short of best)
Further adjustment needed, IMO.
FORD, IIRC, recommends a 50% "return" when WD activated which you about meet. I'd rather go to 100% (or as close as hitch will do it). Check their guidelines for your model truck as that should be the background to your decisions/adjustments (as with GVWR, GAWR, etc, etc).
RA increased by 1,480-lbs w/o WD activated.
With WD activated, 200-lbs "went" to the FA and only 40-lbs to TT axles.
Just not enough leverage by the WDH, yet.
(The Ron Gratz Chart)
Weighing #1 -- TT attached and Weight Distribution Activated
Let Front Axle Load be "FA1" 4760
Let Rear Axle Load be "RA1" 5160
Let TT Axles Load be "TT1" 5660
Then, while in same position on scales, take
Weighing #2 -- TT attached and Weight Distribution Not Activated
Let Front Axle Load be "FA2" 4560
Let Rear Axle Load be "RA2" 5400
Let TT Axles Load be "TT2" 5620
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" 5040
Let Rear Axle Load be "RA3" 3920
From the above values, you can calculate:
TV weight = FA3 + RA3 8960
Gross Combined Weight = (FA1 + RA1 + TT1)
- should also be equal to (FA2 + RA2 + TT2) if scale weights are correct
TT Weight = Gross Combined Weight - TV Weight
15,580 - 8960 = 6,620
Tongue Weight = (FA2 + RA2) - (FA3 + RA3)
9960 - 8960 = 1,000
TW = 15%
Load Transferred to TT Axles
when WD System in Activated = TT1 - TT2
With a 1k TW we'd more likely see around 240-lbs shifted to the trailer axles once the FA weight is "restored" to it's solo value.
While "level" is really only important for the trailer (independent suspension; we want both axles loaded the same as they would not be if the trailer were nose high or low; braking, etc), and slight tail down no big deal for the TV, a better set of adjustments to your hitch will probably pick up the tail a bit.
But there is no doubt that the steering and braking will be improved by further tweaks to the WDH. The more the load on the TT tires, the better will be the combined
braking of the rig. Not to mention best anti-sway.
Once done, with new scale tickets, one can also look at TV tire pressures for best performance within vehicle manufacturer guidelines, and check that TT tires still have a 12-15% load reserve against the WD activated scale value divided by four (TT tires are always to be at maximum sidewall pressure, cold).
Perfect is hard to achieve for some rigs . . but the closer one comes the better will the combination rig perform. And this eliminates a lot of guesswork if in the future "something" doesn't seem right anymore (ask BoondockDad
about whether it was his worn hitch or his new tires causing a hoochie-koochie dance with his rig on a great thread from a little while back. Eliminating problems because one has solid numbers
is a real boon).
Unless you sell either, or greatly
change the loading of one or both vehicles, this baseline is good for many years to come. Just check it every so often the same way. A stack of scale tickets -- updated & clipped in your logbook -- is your very good friend. Confidence in a rig is in real time from real numbers . . but confidence itself
cannot be measured accurately when it comes to the test. Give it some more work. It'll be the best beer you ever earned (you'll say to yourself someday).