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Old 02-25-2013, 09:21 AM   #11
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OnTheGo,

One thing that I have learned over the years when it comes to WDH "physics" and interpreting CAT scale results, there are numerous ways of presenting the same information
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Old 02-25-2013, 09:34 AM   #12
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Quote:
Originally Posted by Raugustin View Post
snip...... I also see that the amount of payload that is shifted from the TV to the TT represents a fairly significant % of the added Tongue weight...... snip
It should be noted in the case of the CAT scale weights used as a reference, that the CAT scale 2nd weigh (WDH engaged) confirmed that to much weight has been distributed to the TV's steering axle (100lbs). Once this as been corrected via WDH adjustment one may see the amount of weight being distributed to the TT's axles decrease do to the decrease in WDH spring bar leverage.

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Originally Posted by Raugustin View Post
snip.... I have just ordered a set of Air-Lift 1000 air bags to fit into the coil springs of the Ram so that I can offset any rear end sag that the WDH doesn't address....what are your thoughts around this and how do these interact and with the WDH or do/can they in-fact address weight distribution without the WDH?
IMO the addition of the air bags will have little, if any effect at all on the TV's steering axle weight. Again, please note that every TV's frame and suspension reacts differently under these types of conditions. If there is a minor effect on weight distribution an air bag can't consistently maintain the distributed weight like a WDH.

Best to think of air bags as means to control the TV's rear end sag, thus providing added stability when under load.

Just thinking out loud here .... as I do often

Bob
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Old 02-25-2013, 12:39 PM   #13
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Bob,

Hereís what I think is happening. With springs bars applied (3rd weight) the TVís rear axle weight is 2940. Before attaching the bars it was 3480. 3480 Ė 2940 = 540

The 2nd weigh axle weights indicate that 320 was distributed to the TVís front axle, and 200 was distributed to the TTís axle. (Thereís 20 lbs left over. Iíll assume thatís scale difference.) So, 540 pounds was distributed from the TVís rear axle. Does the 540 figure represent the strength of the bars, the tilt of the hitch head, and how the bars are attached?

If thatís correct, hereís my next assumption. When amabee applied 620 pounds of hitch weight, the TVís rear axle weight increased to 840 because of the TVís weight shift front-to-rear. After the 540 was distributed to the other axles it left the ďotherĒ 300 pounds as weight on the TVís rear axle, and that 300 lbs is the difference between the 2nd weigh and the 1st weigh.

Hereís what I think we are not seeing as a group. The hitch weight doesnít change, but a portion of the hitch weight (depending on your WDH and how you have it set-up) is distributed away from the rear axle.

So, when you know you added 620 pounds to the hitch, and the TVís rear axle weight increases by only 300, its easy to assume the WDH reduced the hitch weight Ė but thatís wrong. Wow!

Okay, Bob, does all this make sense? Once again, I appreciate it.
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Old 02-25-2013, 01:40 PM   #14
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OnTheGo,

The easiest way for me to respond to your questions was to "reference quote" your entire post for clarity. My comments are in BLUE:

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Originally Posted by OnTheGo View Post
Bob,

Here’s what I think is happening. With springs bars applied (3rd weight) the TV’s rear axle weight is 2940. Before attaching the bars it was 3480. 3480 – 2940 = 540

I think you meant to reference 2nd weigh.

The 2nd weigh axle weights indicate that 320 was distributed to the TV’s front axle, and 200 was distributed to the TT’s axle. (There’s 20 lbs left over. I’ll assume that’s scale difference.) So, 540 pounds was distributed from the TV’s rear axle. Does the 540 figure represent the strength of the bars, the tilt of the hitch head, and how the bars are attached?

That’s one way of looking at…, the size rating and overall adjustment of the WDH directly impacts the weight distribution results. Another minor element that comes into play is how the TT A-frame and TV frame/receiver reacts to the associated WDH forces at hand.

If that’s correct, here’s my next assumption. When amabee applied 620 pounds of hitch weight, the TV’s rear axle weight increased to 840 because of the TV’s weight shift front-to-rear. After the 540 was distributed to the other axles it left the “other” 300 pounds as weight on the TV’s rear axle, and that 300 lbs is the difference between the 2nd weigh and the 1st weigh.

That’s correct.

Here’s what I think we are not seeing as a group. The hitch weight doesn’t change, but a portion of the hitch weight (depending on your WDH and how you have it set-up) is distributed away from the rear axle.

If you mean….; the tongue weight doesn’t change (hitch weight is something else), but a portion of the tongue weight is distributed away from the rear axle…., I concur.

So, when you know you added 620 pounds to the hitch, and the TV’s rear axle weight increases by only 300, its easy to assume the WDH reduced the hitch weight – but that’s wrong. Wow!

Correct, the WDH distributed weight that was a result of the TT tongue weight being placed on the hitch ball.

Okay, Bob, does all this make sense?

Absolutely!


..... snip
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Old 02-25-2013, 02:05 PM   #15
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Thank you, Bob. I owe you a Coke, or a double Coke, or something.
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Old 02-25-2013, 03:48 PM   #16
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Good discussion, I actually think I finally understand all this. I almost can't wait to go reweigh after making my adjustments to see what actually happens. It is actually kind of interesting how this all works.
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Old 02-25-2013, 04:16 PM   #17
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Quote:
Originally Posted by amabee View Post
Good discussion, I actually think I finally understand all this. I almost can't wait to go reweigh after making my adjustments to see what actually happens. It is actually kind of interesting how this all works.
X2

I think this post will be referenced a lot in the future. Very good discussion.

Best regards,
Doug
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Old 02-25-2013, 05:02 PM   #18
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Wow, things are actually coming into perspective for me about the "effect" of weight distribution. I may have to print this entire post for reference, or can we save it somewhere in the JOF for quick reference. Would that be a "sticky?" Great Post, thank you to all. Terry
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Old 02-25-2013, 10:14 PM   #19
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TV Manufacturer's Front Suspension Revisions when using a WDH

Just thought I would take the WDH discussion up a notch, if it's ok with the OP "OnTheGo".....,

We have been discussing the importance of returning a TV's front suspension back to it's "unhitched" condition (weight/height) when using a WDH, which has been an industry standard for years..., but recently Ford and GM have opened this standard up a little.

I always advised that one refer to their specific owners manual to confirm their TV's towing specifications, especially on new vehicles. The following represents what Ford and GM state:

FORD: Specifications for 2011 and newer Trucks say the WDH should be adjusted to eliminate about 50% of the front end rise..., so one would assume that this translate into 50% of the weight removed (this is what I haven't confirmed.

FORD: Specifications for SUV's say the WDH should be adjusted to return the front bumper to within 1/2" of the unhitched height..., safe to assume that this translate into returning the same weight that was removed.

GM: The 2013 Silverado 1500 Owner's manual states that a "weight distributing hitch optional when towing less than 7,000 pounds. Weight distributing hitch is required with fifty percent restoration when towing 7,001 pounds to 9,900 pounds." I don't know what the 2013 Silverado 2500 and 3500 models owners manual state.

I have not seen any Ford or GM documentation with the recent 50% rule stating that returning the TV's front suspension to it's "unhitched" condition (weight/height) is not recommended.

What I'm noodling over:

* What has changed that influenced Ford and GM's specific front suspension revision.

* Does GM's statement of 50% restoration refer to both height & weight?

* What impact does Ford's "50% rise return" have on the same front suspension's returned weight?

Most of the discussions on the "50%" subject (since Ford came out with their revision) that I have had with fellow "towing geeks" concluded that following the "return the same weight that was removed" rule is still good with vehicles referencing the recent "50% rule".

In any case, it is always recommend to refer to one's TV owners manual "Towing Section" for WDH specifications.

Any insight/thoughts into this "50%" subject is welcomed.

Bob
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Old 02-26-2013, 05:44 AM   #20
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Quote:
Originally Posted by TCNASHVILLE View Post
Wow, things are actually coming into perspective for me about the "effect" of weight distribution. I may have to print this entire post for reference, or can we save it somewhere in the JOF for quick reference. Would that be a "sticky?" Great Post, thank you to all. Terry
Terry, ... glad you found the thread useful and informative. Thank you for the kind words.
A “sticky”? I don’t know – your call. IMO Rustic Eagle’s comments were concise and gave credibility to the thread. The questions he answered (mine anyway) were “all over the place”, not always worded properly, and the numbers and weights could have been presented more logically.

The information is there if someone wanted to reference it by searching. But I think if you want to do something permanent, a more well organized document would serve the reader better.

... and Rustic Eagle has started us down a new path. I’m going to answer his post next. So this whole thing is still a work in progress.
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