Front Axle Load Restoration question

[ROBERT CROSS]

Originally Posted by Profxd

You forgot to post the pictures of your weigh tickets in that response Bob.

At least I have some to share....and don't just bloviate.

Bob
🇺🇸

[Profxd]

Originally Posted by ROBERT CROSS

At least I have some to share....and don't just bloviate.

Bob
🇺🇸

Bob, there’s something fundamentally wrong with that depiction of how the Andersen hitch works. Apparently Brian doesn’t see it nor did he answer the question that was asked. All you have to do is look at the scale weight tickets of those that use the Andersen hitch. Weight is transferred forward to the front of the TV and backward to the trailer just like a solid bar WDH. The frame brackets are mounted to frame 29 inches away from the center of the coupler for good reason.

[BayouBiker]

Profxd, the premise of the original question was wrong, I corrected the premise and then answered the question using the correct depiction and a valid example with SilverBamby's trailer.

[ROBERT CROSS]

Originally Posted by Profxd

Bob, there’s something fundamentally wrong with that depiction of how the Andersen hitch works. Apparently Brian doesn’t see it nor did he answer the question that was asked. All you have to do is look at the scale weight tickets of those that use the Andersen hitch. Weight is transferred forward to the front of the TV and backward to the trailer just like a solid bar WDH. The frame brackets are mounted to frame 29 inches away from the center of the coupler for good reason.

Granted...but it does take much more effort/force to move the same weight, considerably less purchase without the bars.
With a lighter TW an adequate choice, 1200# not so much.🤔

Bob
🇺🇸

[BayouBiker]

Actually bob it takes much less effort (tension on the force generating component and all structural components), on the order of 1/3 to 1/2 to move the same weight. If there is a fault with the Andersen, it's components are undersized for very large trailers.

[ROBERT CROSS]

Originally Posted by BayouBiker

Actually bob it takes much less effort (tension on the force generating component and all structural components), on the order of 1/3 to 1/2 to move the same weight. If there is a fault with the Andersen, it's components are undersized for very large trailers.

Well yes, undersized.
Kind'a like if my haha WD bars were a foot shorter?

If the Andersen was bigger.
How much & what's bigger? Larger ball, heavier chains, bigger bushings.
Being 'undersized' is NOT a design flaw?

To my MacGyver brain it's like a wheelbarrow with 6" handles.🤔

Bob
🇺🇸

[jadatis]

The 50% reduction is on rear axle, and is devided over front axle of TV and axle('s) of TT.
If single axle TT about even, but if tandemaxle more to front of TV and only little to tandemaxles of TT.

From the weightslips of Robert Cross in post #9, I assume he has tandem-axle TT.

I think even, that if you load up the TV on rear axle, also that weight is shifted to F TV and TT.
The WDH does not know what is the TV and what the TT.
Makes slightly one stiff vehicle of both,compare a caterpillar , wich in fact has no " rear axle" of TV , with only Frontaxle of TV and 1 TT axle, with a verry stiff WDH in the middle.

[BayouBiker]

IDK Bob, 600 lb bars are undersized for a tongue weight of 1200. Is that a design flaw? Does a Suburban have a design flaw because it can't tow a 20,000 lb trailer?

[ROBERT CROSS]

Originally Posted by BayouBiker

IDK Bob, 600 lb bars are undersized for a tongue weight of 1200. Is that a design flaw? Does a Suburban have a design flaw because it can't tow a 20,000 lb trailer?

Yes...600 would be undersized if you 'designed' to use them when 1000 & 1200 were available.
POI 600 not available for PPP's.

Whats' available to 'design' an Anderson to move more for an 800+lb TW?
The Burb is not designed for 20k just as the bushing hitch is not designed for heavier TW's.

Bob
🇺🇸

[captainkirk]

Disregarding all that others have said here is my .02 "feelings" not to be confused with facts as there are so precious few we can agree upon.

What type of weight distribution hitch should you buy...looking at the picture in the Ford manual you referenced their using a Reese Dual Cam hitch which interestingly enough would have been my recommendation.
I personally like this design because it has a definite hard detent built in the design when the trailer passes through the center position which really helps prevent sway.

As to the question about the loading of the front end to return 50% of the increase in height towards the no load condition...follow the Ford manual here as these are the guys that built the truck they know why and what their doing.

They built the truck and they would suffer the repercussions if their statements were wrong...ask yourself "is anyone here likely better to answer this question than the guys that built the truck?" Answer: Not likely is the way to bet.
It would be very interesting the hear Ford's reasons for doing this given the common thought that you return the nose to the original height and it seems to contradict the hitch manufacturers instructions?

The diagram of the Anderson and the normal WDH hitch seem confusing to me... yes the arrow forces are correct at the end of the chains and at the end of the bars respectively for each design, but the rotational forces at the hitch seem to be reversed if their going to force the nose of the tow vehicle down.

The pictures might be correct from an engineering review given the terminology but from a layman's perspective the forces rotate clockwise in both hitch design cases or the front of the truck would not go down it would go up. To me it's a confusing diagram even if it's technically correct it's not very usable to the common man.
We could debate the diagrams all day but in the end it still was confusing.

(I would personally like to thank the original poster with the questions for taking the "Pro Pride" hitch out of the discussion at the beginning this was very smart from a tactical standpoint...kudos.)

Note to all the "experts" currently loading their responses... these are my stated "feelings" and as the saying goes "You shouldn't argue with a mans feelings".

Now better to run and hide than to stand and fight is my motto! Better yet "Do what you want to the girl but leave me alone".

[BayouBiker]

The Andersen has a practical limit of about 750 lb. shifted off the rear axle. Enough to return 65%-70% to the front axle when tongue weight is 1400 lb using typical vehicle geometries. Some may say this is not enough weight transfer for a 1400 lb tongue and therefore the Andersen is undersigned for its advertised specs. Others would argue 70% is a reasonable target.

Ford recommends 50% max when you're towing a trailer that is at the vehicle's stated limit. SAE has a paper on this describing how addition of 50% more (to 100%) when at the upper towing limits and the limit is due to understeer gradient reduces cornering capability by 25% or more. This is the basis for Ford to make this recommendation.

Is Ford and the writers of the SAE technical paper wrong? No of course not. the 50% guidance is important to follow if you're towing near the vehicle's upper limits.

The directions of the arrows are somewhat arbitrary since they are vector diagrams. The opposite direction is just negative in the reference system the author chose. The pictures however are not correct because they are incomplete and don't account for or display the additional torque moments being generated.

[captainkirk]

Originally Posted by BayouBiker

The Andersen has a practical limit of about 750 lb. shifted off the rear axle. Enough to return 65%-70% to the front axle when tongue weight is 1400 lb using typical vehicle geometries. Some may say this is not enough weight transfer for a 1400 lb tongue and therefore the Andersen is undersigned for its advertised specs. Others would argue 70% is a reasonable target.

Ford recommends 50% max when you're towing a trailer that is at the vehicle's stated limit. SAE has a paper on this describing how addition of 50% more (to 100%) when at the upper towing limits and the limit is due to understeer gradient reduces cornering capability by 25% or more. This is the basis for Ford to make this recommendation.

Is Ford and the writers of the SAE technical paper wrong? No of course not. the 50% guidance is important to follow if you're towing near the vehicle's upper limits.

The directions of the arrows are somewhat arbitrary since they are vector diagrams. The opposite direction is just negative in the reference system the author chose. The pictures however are not correct because they are incomplete and don't account for or display the additional torque moments being generated.

See it's well thought out....very informational without adding conflict, it contains good references and avoids making finite statements when there's a range of answers.
All this and he seems to agree the diagrams might be technically correct but somewhat misleading.

Kudos for all you said and all you avoided...super well worded.

[Profxd]

Originally Posted by captainkirk

See it's well thought out....very informational without adding conflict, it contains good references and avoids making finite statements when there's a range of answers.
All this and he seems to agree the diagrams might be technically correct but somewhat misleading.

Kudos for all you said and all you avoided...super well worded.

Well thought out but if only were fact and not opinion.

[mefly2]

Very entertaining if not all that informative !
RobertCross ... just what does bloviate mean ???
Never mind, DW just looked it up ... LOL
Great addition to my vocabulary and I'm not a politician !
ROFL ...
Joey - Watching to see just how the Expy XL works out for you.

[joeysmith]

I spent some time incorporating the great feedback all have provided and did some measurements at the CAT scales...

1. Adjusted Hitch Weight
I moved equipment around in the TT to aim to hit 12-13% on the hitch weight (relative to the TT weight). I had too many heavy items in the back trunk area and I had also recently upgraded my batteries from AGM to Lithium and I believe that may have resulted in reduced hitch weight. I was heading towards 11%...

2. Moved equipment out of TV and to TT
Based on this thread, multiple comments cropped up suggesting to try this to help reduce stress on the TV. I have not been able to move heavy items into the rear seat area as it would be crowded for the kids (& dog) that are back there...


I have been able to dial in my Andersen hitch settings to choose between two options:

Option A: Andersen spring compressed to 1 3/4" [10 threads]
FALR: 44%
Drive Axle: 4340 lbs (Rear GAWR is 4380lbs -> 40 lbs margin)

Option B: Andersen spring compressed to 1 11/16" [11 threads]
FALR: 69%
Drive Axle: 4240 lbs (Rear GAWR is 4380lbs -> 140 lbs margin)

Any pointers on whether to aim for having more margin on Rear GAWR vs staying at 50% or below on FALR? I do not have a good sense of which would be better and what I would be optimizing by choosing one setting over the other...


======================
CAT Scale Data
[Steer Axle, Drive Axle, Trailer Axle, Total]
TV Front GAWR = 3550, TV Rear GAWR = 4380

1. TV Only [3160, 3500, NA, 6660]
2. TV+TT (No WDH) [2840, 4540, 5000, 12380]
3. TV+TT (1 3/4" compression) [2980, 4340, 5040, 12360]
4. TV+TT (1 11/16" compression) [3060, 4240, 5080, 12380]

Based on above, hitch weight is 720lbs and TT weight is 5720 (12.6%)

Andersen hitch remains at 29" and I did add a hitch clamp and tried reducing the rattle in the hitch ball using a shim. Not sure if that did much though. However at this point, I am not yet needing the Andersen to shift any more weight given my current payload and goals of staying around 50% FALR.

[BayouBiker]

At this point you are in the ballpark. Start with ten to ten and a half next trip and pay attention to steering response, porpoising ( excessive pitch), and yaw when large vehicles pass. If any of this seems excessive, add a turn, if not, leave it. For a short time add two turns just for comparison, the springs can safely be compressed more than the guidance. Also watch your TPMS to see how much front and rear vehicle tires warm while driving. If the rears increase pressure by more than 10% and more than fronts, add a couple pounds.

You look to be in great shape.

[joeysmith]

Originally Posted by BayouBiker

At this point you are in the ballpark. Start with ten to ten and a half next trip and pay attention to steering response, porpoising ( excessive pitch), and yaw when large vehicles pass. If any of this seems excessive, add a turn, if not, leave it. For a short time add two turns just for comparison, the springs can safely be compressed more than the guidance. Also watch your TPMS to see how much front and rear vehicle tires warm while driving. If the rears increase pressure by more than 10% and more than fronts, add a couple pounds.

You look to be in great shape.

Thanks for the feedback. I drove around a bit with the setting at 11 and all felt fine. Will try at 10 - 10 1/2 to see if there is any difference.