Performance Testing The Andersen Hitch

[GCinSC2]

Originally Posted by PB_NB

I couldn't wrap my head around how it achieved the uplift on the hitch.!

Not the same but for grins.

Ever use a chainsaw on a fallen log that has weight on each end but you’re trying to cut in the middle. As you cut the saw kerf closes and it will bind up the bar and chain. But if you put a wedge in the top of the cut and tap it in as you cut that cut doesn’t bind the saw but it raises the log right at your cut.

And now back to your regular program.

[PB_NB]

Originally Posted by GCinSC2

Not the same but for grins.

Ever use a chainsaw on a fallen log that has weight on each end but you’re trying to cut in the middle. As you cut the saw kerf closes and it will bind up the bar and chain. But if you put a wedge in the top of the cut and tap it in as you cut that cut doesn’t bind the saw but it raises the log right at your cut.

And now back to your regular program.

That makes sense!

I understand where the force is coming from by tightening up the nuts and pulling on the cone assembly. It just seems that the lever is short at the cone so the force/tension on the chains needs to be high to achieve an upward force at the ball.

It seems that red poly could be replaced with a denser material that is less prone to cracking or bulging but still behave with similar design principles??

[tlars]

Originally Posted by BayouBiker

I am sorry, I have been describing the springs as neoprene but as you pointed out, I should have said urethane. Thanks for that. The general formula for pad and cylindrical springs is:
L=D x Y x (1+2f^2) where

D = % of deflection/inch of thickness
L = load in psi
Y = Young's Modulus (approximately 3500 to 4500 psi)
f = shape factor (pressed area divided by free area)

The polyurethane springs used by Andersen will competently produce approximately 1000 psi each at the max recommended 25% deflection. The generated tension is roughly linear in the useful range.

Thus for a 600 lb tongue weight you would compress the springs roughly 42% of what would be required for a 1400 lb tongue weight. The dynamic range of motion and change in tension will be nearly the same for both tongue weights in response to terrain and suspension travel because of the near linear character.

For towing setup, it is correct to adjust the ball height to level the trailer. Chain tension is used to adjust weight distribution. You are correct that weight distribution should not be used to level the trailer. I have my instructions in hand. It correctly says to use WD tension to level the TOW VEHICLE. It also correctly says to adjust the ball up or down to get the trailer within 1 inch of level when tension is optimal for tow vehicle attitude and weight distribution.

As far as Eye balling it, Andersen is mostly correct that tow vehicle attitude is an excellent proxy for proper distribution. Fine adjustment would be made on the road as others have previously described to optimize ride, suspension performance, steering response, and sway damping. The CAT scales are great to confirm the set-up, is important for vehicles close to towing limits where oversteer is an issue, and are necessary to address specious arguments from naysayers.

Wow several things to uwrap. First off, I'm certainly not doubting that the Hitch does perform for your application. You bought it, you like it, everything is fine.
I also believe that Anderson hitch is an ideal application for Urethane die springs. Much less weight hanging off my back end.
My beef is that they should be offering several options for different weight trailers.Just like other hitch companies that offer different strength bars. Your formulation has typos in it but I know it well. It speaks to Anderson's flawed decision to offer only one spring for all weights. (It's likely an advantage for dealers by reducing stock keeping units.
You always want the full range of motion whe you design a spring application (cars, trailers, etc, etc.)
My application with 600 lbs or so on my wimpy GLE will enjoy the full travel of the Anderson hitch when I enter my neighbors drive that seems to have 30 % grade coming off a very heavily crowned road. I should make it if the propane tanks don't come through the back hatch.
Had I had a 14000 lb tongue weight I would have had to preload (compress) the urethane spring twice as far leaving half as much travel. In this case my wimpy GLE gets a frame modification giving it a permanent smile. Anderson could have saved the day by offering a spring that would hold the 1400 lbs and still offer the same full travel.

[BayouBiker]

Originally Posted by kscherzi

I get you're in love with this hitch but you don't need to belittle others with different life experiences to support your opinion.

I think "impressed by" is a better term than "love" and on that point I would say I am impressed by the Hensley and Propride hitches. I was unsure about the Andersen Hitch and I found the earlier discussions incomplete and inconclusive. I also found my Blue Ox to be a bit harsh on the trailer. So I decided to install the Andersen I had sitting in my garage for the last couple years and give it an objective test. I think making follow up posts that directly contradict claimed statements of facts by instead describing them as life experiences is a very polite and clever way to call someone a liar, and someone should not be surprised if they are called out on it. A plausible technical explanation for the difference would have been useful, and it would have revealed a more helpful motive. Otherwise there is no way for a casual reader to determine what is more correct.

I got my copy of the Anderson hitch in late 2012. I did install it correctly, pretty hard to not. Maybe Anderson has since modified their design but after just two trips the biggest failure was the conical brake pad material distorting and oozing out of the hitch head, maybe a half inch of material. Others with this hitch at the time were also experiencing the same result. Didn't look good for the long term.

To get enough weight distribution for my rig, a Ford Expedition, and trailer tongue of 950 lbs, I needed to torque the washers to the point where they were sucking into the bulging red neoprene parts. I forget the exact number, but it maxed out somewhere between 200 and 300 lbs off the rear axle by CAT scale.

As I previously described, it is very easy to make installation errors. Earlier I previously confirmed Andersen did upgrade to harder springs and bushings and offers free replacement if the earlier parts fail to perform.

Excessive flexibility and slop in the coupler, ball, shank, and receiver mounts will also make it difficult to redistribute weight, particularly for a system that relies on limited adjustment lengths. One could fault the hitch design, but it is a miss-assignment of fault.

The last straw was when Anderson posted on their website that their WD hitch was incompatible with the trailer coupler welded on my trailer as installed by Airstream. This was after I purchased their hitch, and they wouldn't take it back for refund.

Again this issue was fully addressed in previous posts including solutions to the issue. What purpose is served by regurgitating it?

Like I mentioned earlier, maybe Anderson has corrected flaws in their hitch these past 7 years, but that's my experience with this hitch. Glad you're happy with it. I wasn't and have moved on.

If you've moved on you are not here to learn, so what is your purpose of attacking recent objective observations with old data if not to throw it into question.

[BayouBiker]

tlars, first I double checked the formula and don't see any errors. Second, maybe I am not seeing the issue correctly and if not perhaps you can help me better understand. I'm going to assume we agree on the objective of WD for the case where the system is static in pitch. Spring rate and deflection would not matter so a single hardness would work fine so long as it is sufficiently hard for the full range of tongue weights. Let's make sure we agree on the objective for dynamic situations. First we need to agree on what is the full range of motion. Second the tension profile throughout that range of motion. Then we can assess whether a range of hardness's is better than a single hardness. As I write this, I don't know the answer so I may learn something. The considerations for safe full travel is we don't want the trailer to scrape and we don't want the tow vehicle rear spring to unload more than 50% or to bottom on the stops. Looking at a range of setups +/-2 inches of vertical ball travel covers 80% of cases and the range of motion is roughly the same regardless of tongue weight, correct?

If I understand your argument, you believe for all tongue weights, the same percentage of tension should be unloaded on positive (upward) travel and same percentage of tension should be added on negative travel.

Andersen's design has the same absolute magnitude of tension unloading and loading regardless of initial tongue weight.

Are we in agreement?

[Fair_Enough]

Originally Posted by jaybauman

I'm a ProPride guy through and through, but having just sold my trailer and hitch, I'll need to get a new hitch when my new trailer comes in. I understand how the Andersen distributes weight. But to me, the sway mitigation is a black box on this product. How does it accomplish this?

Of course I'm likely to stick with what I know for my Classic 33, but would the Andersen practically work for WD on a 10,000 GVWR trailer? My TV is in my sig below, so I really only transfer enough weight to make for a comfortable ride (~25% FALR on FC30 w/ ProPride).

Thoughts?

How does it control sway: chains attached to the the brackets on the A-frame are then attached to a delta shaped plate on the bottom of solid shaft that runs up to the ball mount. The union between this shaft and the housing is lined with a friction material, which allows, but resists (if that is the best term), the shaft from turning in the union or pocket. The trailer hitch doesn't rotate on the ball. It still moves some, but the rotation (left and right) is the shaft with ball and delta plate inside of the pocket surrounded by friction material being force to turn by the pull of the chain (a chain) while turning.

A quick comment about 10K GVWR towing. Short answer is yes it will work as good as, or better than any brand I have ever used if not considering Propride or Hensley.

My SOB initially had a Reese Dual-Cam that I didn't like the work necessary each time dialing it in. Enter Anderson. No "dialing in" learning curve and far smoother over less-than-perfect road surface.

By the way... avoid the skewed plate at hook up issue by either disconnecting the chains while straight, or rehitching at the same angle you unhitched at. KISS principle.

What I noticed as soon as I hit the road was this: how incredibly poor condition of our interstate highways have become... passing unpleasant shake and bounce between tow and towed, which was clearly exasperated by a heavy trailer. No WDH hitch can make that go away. I did some things to try to make it better, but only heard of a hitch called "Air-safe" after selling the SOB. That, I think would be the real solution to the road shock.

Best wishes,
FE

[tlars]

Originally Posted by BayouBiker

tlars, first I double checked the formula and don't see any errors. Second, maybe I am not seeing the issue correctly and if not perhaps you can help me better understand. I'm going to assume we agree on the objective of WD for the case where the system is static in pitch. Spring rate and deflection would not matter so a single hardness would work fine so long as it is sufficiently hard for the full range of tongue weights. Let's make sure we agree on the objective for dynamic situations. First we need to agree on what is the full range of motion. Second the tension profile throughout that range of motion. Then we can assess whether a range of hardness's is better than a single hardness. As I write this, I don't know the answer so I may learn something. The considerations for safe full travel is we don't want the trailer to scrape and we don't want the tow vehicle rear spring to unload more than 50% or to bottom on the stops. Looking at a range of setups +/-2 inches of vertical ball travel covers 80% of cases and the range of motion is roughly the same regardless of tongue weight, correct?

If I understand your argument, you believe for all tongue weights, the same percentage of tension should be unloaded on positive (upward) travel and same percentage of tension should be added on negative travel.

Andersen's design has the same absolute magnitude of tension unloading and loading regardless of initial tongue weight.

Are we in agreement?

Brian,
This is very simple. Using the same urethane spring for two applications where one requires twice the force of the other is simply inappropriate. It's a compromise that does not need to be made. They stock hundreds of springs for this very reason.
It makes sense that Anderson would prefer to sell just one WD hitch with just one spring option for every application. Dealers selling to less demanding applications (utility ,equipment and other trailers) likely find this appealing.

Watch the Anderson videos. They do not talk the language (Cat Scales, Axe loading) I read in this forum. They talk eye balling, close enough, raise the ball if this does not level the trailer. I'm happy for you if this fits your application but I don't see any indication it would be best for mine.

[BayouBiker]

tlars, you previously made that argument and you presented your assumptions of the manufacturers motives with prejudice. I was hoping to explore the technical rationale behind your claim that it is inappropriate to use linear and equal force multiplication for different tongue weights compared to a different and still undefined strategy you think is somehow better. I was hoping you would better describe the approach you favor and present a physics/mechanics based argument supporting it; perhaps show how it would perform better with respects to the objectives of WD tension systems. Perhaps I need to re-calibrate my expectations.

[jaybauman]

Originally Posted by Fair_Enough

How does it control sway: chains attached to the the brackets on the A-frame are then attached to a delta shaped plate on the bottom of solid shaft that runs up to the ball mount. The union between this shaft and the housing is lined with a friction material, which allows, but resists (if that is the best term), the shaft from turning in the union or pocket. The trailer hitch doesn't rotate on the ball. It still moves some, but the rotation (left and right) is the shaft with ball and delta plate inside of the pocket surrounded by friction material being force to turn by the pull of the chain (a chain) while turning.

I think I get the concept, but maybe not. So let me ask a few basic questions.

Does this technology rely on friction to reduce sway? And if so, does this friction occur between the urethane bushing and some type of collar? And how does static friction coefficient compare to kinetic friction coefficient? In other words, is it hard to get started but easy to keep moving when started?

Or does this mitigate sway by taking advantage of elastomeric properties of the urethane, i.e. torsion on the urethane bushing?

Apologies for the basic questions and please forgive/correct me if I am really off-base with my understanding. I like the simplicity (and relative cost!) of this hitch, but I am unsure if this is worth exploring further....

[BayouBiker]

Jay, the design uses friction between the urathane bushing and the milled steel ball cone shaped extension and also the milled aluminum alloy housing. The coefficient of kinetic Friction is about 1.5 and static is about 2.0, but the kinetic factor is overriding for sway since it is a dynamic instability.

[kscherzi]

Originally Posted by BayouBiker

I think making follow up posts that directly contradict claimed statements of facts by instead describing them as life experiences is a very polite and clever way to call someone a liar...

Wow! What a nice open mind you have. Hey, in your first post you ended with "Comments are welcome." This is a public forum. I gave my opinion of this hitch based on my real life experience with my trailer and my tow vehicle (post #25) to which you felt the need to add a snarky condescending response because it didn't fit your narrative. As if only your facts, not others, matter. To have a different opinion based on a different experience is not to call you a liar, but a point of data for others to weigh. And yes, to repeat again, I did install it correctly.

For future reference, when asking for comments use the following phrase, "Comments are welcome, but only those that support my viewpoints".

Another point of data largely glossed over in this thread is the fact that the Andersen Hitch company does not recommend their hitch be used with Atwood 88xxx series couplers, it can lead to catastrophic failure. This point needs to be emphasized as nearly all newer Airstream trailers made in the last 10 or 20 years have this coupler welded on front. So buyer beware. This is an Airstream forum btw. A link to their website and warning below.

https://help.andersenhitches.com/faq...ribution-hitch

Lastly, for your reading pleasure, here's a link to an exhaustive 2,400 long post on this hitch. Lot's of analysis, real life experience, and opinion. https://www.airforums.com/forums/f46...92131-121.html

Feel free to rebut. I know you must, but I'm done with this.

[tlars]

Hey Brian, Let's take a break. I'm curious about your ride. My guess is that it's not stock.

[BayouBiker]

Motivations generally become clearer with each response.

Incompatibility with the Atwood 88xxx coupler can lead to excessive wear and damage to the coupler and ball if excessive play is not removed with addition of a shim and by removing play in the lift handle safety latch. Wear and damage has not and cannot lead to catastrophic failure without intentionally defeating at least two safety mechanisms and three primary attachment mechanisms. Reliability engineers would describe the risk of catastrophic failure as nill. To use that term is being over dramatic.

I suspect many won't want to hassle with shims, tinkering or coupler replacement. This may not be a good hitch choice for those people.

[batman]

Brian,
I for one would like to commend you for your report of the Anderson Hitch. Your research and knowledge of the product adds to the content of the discussions here immensely. This is exactly why I am a member of this forum. Practical (if not expert) advice and personal experience is a good thing to share. Your attention to detail is impressive. I hope you will not be offended by mine or other's "opinions". (FYI, I could never buy a product from Anderson.) You have done a commendable job representing your facts. Not everyone will agree on any subject. Bravo!

-Dennis

[tlars]

Originally Posted by batman

Brian,
I for one would like to commend you for your report of the Anderson Hitch. Your research and knowledge of the product adds to the content of the discussions here immensely. This is exactly why I am a member of this forum. Practical (if not expert) advice and personal experience is a good thing to share. Your attention to detail is impressive. I hope you will not be offended by mine or other's "opinions". (FYI, I could never buy a product from Anderson.) You have done a commendable job representing your facts. Not everyone will agree on any subject. Bravo!

-Dennis

i agree !

[Fair_Enough]

Originally Posted by tlars

Brian,
They talk eye balling, close enough, raise the ball if this does not level the trailer

I thought this was discussed. The TV should be level when the ideal weight is transferred / distributed. I would think the eye is a good tool to determine level. This isn't rocket surgery.

How level the trailer sits after getting the TV level, is controlled by the height of the ball. Adjust the ball (assembly) on the rack and repeat if necessary. Of course, that will require having the proper rack.

I also have wondered about one size fits all spring... what about one size fits all friction sleeve? It then occurred to me that the spring is there to absorb shock, not to add tension. Of course the pressure is passing through and compresses it. Does the shock absorbing characteristic of this spring change depending on compression? Does the small trailer need less shock absorption and the heavier more to provide a smoother ride? Does this one size fits all spring actually work properly?

FE

[tlars]

Originally Posted by Fair_Enough

I thought this was discussed. The TV should be level when the ideal weight is transferred / distributed. I would think the eye is a good tool to determine level. This isn't rocket surgery.

How level the trailer sits after getting the TV level, is controlled by the height of the ball. Adjust the ball (assembly) on the rack and repeat if necessary. Of course, that will require having the proper rack.

I also have wondered about one size fits all spring... what about one size fits all friction sleeve? It then occurred to me that the spring is there to absorb shock, not to add tension. Of course the pressure is passing through and compresses it. Does the shock absorbing characteristic of this spring change depending on compression? Does the small trailer need less shock absorption and the heavier more to provide a smoother ride? Does this one size fits all spring actually work properly?

FE

I completely agree with your statement about "How level the trailer sits....." but the video did not say "after the TV is level" maybe I'm being too picky.

My main point is that it seems clear to me that Anderson designed and markets this hitch to a different croud than others hitches. They do not suggest measuring the hight of your TV in two locations. Eye balling is close enough.
Direct quote from Anderson WD installation instructions:
Trying to get the Tow Vehicle perfectly level is NOT necessary — you just don’t want to be too
extreme in either direction (too much towards the tow vehicle’s front axle or too much towards the rear axle).
After
hundreds of installations we have found that it is quite effective to basically “sight level” the tow vehicle and get it as close
to level as you can by tightening/loosening the Tension Nuts

I'm not saying they are wrong or right. But I think I've learned something from these threads and I'll be measuring my wheel wells and running my rig over the scales three times. I'm just not in their target market.

I'll let Brian explain the geometry of the hitch and function of the springs.

[BayouBiker]

Given the interest, I'll continue on the topic of ideal springs:

In typical WD hitches, full range of ball motion (vertical ball displacement) is achieved with spring/deflection of the bars. The manufacturers specify different bar strengths because the relatively large degree of deflection required to obtain full range of ball motion would have the bars completely unloaded for light trailers well before maximum positive ball displacement, compromising sway performance at a critical time and dramatically reducing pitch damping (porpoising).

The Andersen uses chains in tension which offers very little stretch so it requires springs to achieve required range of motion. If the compression distance required to achieve full ball motion caused chain tension to become unloaded for light trailers then the Andersen design, like the vertical tension bar design, would also require different spring rates. However this is not the case so the Andersen engineers have a choice and this gets to the question posed.

Since the Andersen primarily uses the ball shaft and bushing for friction, sway damping is only partially compromised when chain tension is reduced. Thus other factors can be considered in the final choice. So it is more difficult to intuitively determine what choice is best. Perhaps longevity/durability of the spring. Maybe loading and unloading with equal force magnitudes performed better in road tests than equal percentage. Maybe there was no practical difference. We can explore this from a theoretical perspective a bit more, but I think from here it would require live testing.

[BayouBiker]

I removed the tongue latch lever so I could add a shim under the lever arm that would eliminate most of the vertical play in the fork lever arm so the lever tab won't slam into and damage the shark fin tab. You can see both the fork lever and the shark fin in the first photo.



I used a seatbelt slack retaining clip as the shim and I bent it to lay flat by avoiding the weld material. Another option would have been to build up the height of the latch lever



Eliminating vertical movement is important to prevent the fork from sliding up the ramp and creating more slop between the ball and fork.



Ground off the excess material with a cutter and grinder and painted it.



I will post more photos of the sim I used between the fork and fork ramp to eliminate play between the ball and the fork.

[joeysmith]

I have a 2017 FC 23D and am towing with 2019 Ford Expedition Max XLT, 4x4 (with HD tow package and Payload of 1767lbs).

I am using the Andersen WD hitch and was wondering what the limits are in terms of adjusting the tension nuts to shift more weight to the TV front axle.

I called Andersen and they told me to try and make sure the Urethane springs do not measure to be < 1 3/4”.

I am concerned because I have tuned the tension nut without any fresh water in the tank (with the multiple weighings at the CAT scale). With the current setup, the Urethane springs are already slightly lower than 1 3/4” already.

I am wanting to be able to fill my water tank for some future trips at sites that have no water hookups. I am certain I will be needing to further tighten the tension nut to help shift weight to the TV front axle when I head over to the CAT scale with fresh water tank filled up.

Does anyone know if Andersen’s support call person is correct in that I need to keep the Urethane spring to be > 1 3/4” after adjusting the tension nut?

Thx!