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 > Weight Distribution with sway control question

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LarryJM

NoVa

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Posted: 04/10/20 04:46pm Link  |  Quote  |  Print  |  Notify Moderator

Huntindog wrote:

ScottG wrote:

The beauty of the dual cam is it actually pushes the trailer back in line with the tow vehicle.


X2. The Dual Cam is superior to the 4 point system. The 4 point doesn't try and stop sway it just slows it, and then slows it from returning. The DC will resist sway and if it does move will be forced back to center.

If it really worked like that with any signifignant force, it would be dangerous in slippery conditions when turning in a curve.

It doesn't and it isn't.


100% correct and those thinking the dual cam "forces or pushes" anything simply DO NOT UNDERSTAND how all these friction based systems work and it's too bad this BULL is mentioned anytime any talk concerning sway control systems is brought up.

Larry


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RAINKAP INSTALL////ETERNABOND INSTALL


LarryJM

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Posted: 04/10/20 05:02pm Link  |  Quote  |  Print  |  Notify Moderator

Below is a post from Ron Gratz made HERE several years ago explaining specifically how both the Equal-i-zer and DC cam systems work:

The Dual Cam is a friction based anti-sway system. I discussed how it differs from the Equal-i-zer in my previous post. I do not know the magnitudes of anti-sway torques which can be generated by these two systems; but, I'm working on that.

A difference between Equal-i-zer and Dual Cam which I did not address is how the sway control affects the ability of the TV and TT to realign once they have developed a relative yaw angle. The Equal-i-zer will produce the same resisting torque whether the TT is trying to move away from the "centered" position or moving away from it. The DC, by virtue of the sloping surfaces on the ends of its WD bars will provide more resistance to moving away from center than to moving toward center. Some see this as an advantage in helping to get the vehicles realigned after a lane change, rounding a curve, etc.

The Equal-i-zer differs from a friction-bar anti-sway system in two important ways:
1) It can generate anti-sway torque directly via the trunnions and seats, and
2) It can generate much more torque.
A friction bar simply produces a tension or compression in the bar which, in turn, pushes or pulls on the ball to which the end of the bar is attached. This generates a torque on the hitch which helps to control sway.

The most commonly used friction bar has an adjustment which determines how much tension/compression it can produce. The magnitude of this is factory-set at 1100#. The center-center distance between the friction-bar ball and the main ball is 5.5". Therefore, at the factory setting, this friction bar can generate about 500 ft-lbs of torque. If you installed one of these bars on each side of the A-frame, the pair could generate about 1000 ft-lbs.

One difference between the friction-bar control and the DC and Equal-i-zer is that the friction force on the friction bar can easily be "turned off". Some people believe this is an advantage when towing in reduced-traction conditions.

Ron


You can readily see that there is NO PUSH OR FORCE in how the DC Cam system works. The cams with their slope only change the amount of "FRICTION RESISTANCE" depending on how far off the trailer is from centerline.

Larry

Lynnmor

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Posted: 04/10/20 06:54pm Link  |  Quote  |  Print  |  Notify Moderator

LarryJM wrote:



The most commonly used friction bar has an adjustment which determines how much tension/compression it can produce. The magnitude of this is factory-set at 1100#. The center-center distance between the friction-bar ball and the main ball is 5.5". Therefore, at the factory setting, this friction bar can generate about 500 ft-lbs of torque. If you installed one of these bars on each side of the A-frame, the pair could generate about 1000 ft-lbs.

One difference between the friction-bar control and the DC and Equal-i-zer is that the friction force on the friction bar can easily be "turned off". Some people believe this is an advantage when towing in reduced-traction conditions.



Since the friction bar can and should be adjusted, where did you get the "factory-set at 1100#" figure?





ScottG

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Posted: 04/10/20 08:35pm Link  |  Quote  |  Print  |  Notify Moderator

LarryJM wrote:

Below is a post from Ron Gratz made HERE several years ago explaining specifically how both the Equal-i-zer and DC cam systems work:

The Dual Cam is a friction based anti-sway system. I discussed how it differs from the Equal-i-zer in my previous post. I do not know the magnitudes of anti-sway torques which can be generated by these two systems; but, I'm working on that.

A difference between Equal-i-zer and Dual Cam which I did not address is how the sway control affects the ability of the TV and TT to realign once they have developed a relative yaw angle. The Equal-i-zer will produce the same resisting torque whether the TT is trying to move away from the "centered" position or moving away from it. The DC, by virtue of the sloping surfaces on the ends of its WD bars will provide more resistance to moving away from center than to moving toward center. Some see this as an advantage in helping to get the vehicles realigned after a lane change, rounding a curve, etc.

The Equal-i-zer differs from a friction-bar anti-sway system in two important ways:
1) It can generate anti-sway torque directly via the trunnions and seats, and
2) It can generate much more torque.
A friction bar simply produces a tension or compression in the bar which, in turn, pushes or pulls on the ball to which the end of the bar is attached. This generates a torque on the hitch which helps to control sway.

The most commonly used friction bar has an adjustment which determines how much tension/compression it can produce. The magnitude of this is factory-set at 1100#. The center-center distance between the friction-bar ball and the main ball is 5.5". Therefore, at the factory setting, this friction bar can generate about 500 ft-lbs of torque. If you installed one of these bars on each side of the A-frame, the pair could generate about 1000 ft-lbs.

One difference between the friction-bar control and the DC and Equal-i-zer is that the friction force on the friction bar can easily be "turned off". Some people believe this is an advantage when towing in reduced-traction conditions.

Ron


You can readily see that there is NO PUSH OR FORCE in how the DC Cam system works. The cams with their slope only change the amount of "FRICTION RESISTANCE" depending on how far off the trailer is from centerline.

Larry


Well Larry, as a retired engineer I do understand how such things work and I can explain how lateral force is generated but I don't think you're open to a civil discussion about it. So, there's no reason for me to attempt to do so. We'll just have to agree to disagree.
One thing is for certain, there is absolutely no friction material employed in the DC.

Good luck to you.

* This post was edited 04/10/20 08:46pm by ScottG *


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Huntindog

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Posted: 04/10/20 08:55pm Link  |  Quote  |  Print  |  Notify Moderator

Lynnmor wrote:

LarryJM wrote:



The most commonly used friction bar has an adjustment which determines how much tension/compression it can produce. The magnitude of this is factory-set at 1100#. The center-center distance between the friction-bar ball and the main ball is 5.5". Therefore, at the factory setting, this friction bar can generate about 500 ft-lbs of torque. If you installed one of these bars on each side of the A-frame, the pair could generate about 1000 ft-lbs.

One difference between the friction-bar control and the DC and Equal-i-zer is that the friction force on the friction bar can easily be "turned off". Some people believe this is an advantage when towing in reduced-traction conditions.



Since the friction bar can and should be adjusted, where did you get the "factory-set at 1100#" figure?
Just read the directions. The bar has a lever on one side and a bolt on the other. The lever is supposed to cranked down all the way every time. The bolt can be used to adjust it. The factory presets this bolt.

I know that many here adjust them with the lever, but the intructions specifically state not to.


* This post was edited 04/10/20 09:02pm by Huntindog *


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Huntindog

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Posted: 04/10/20 08:57pm Link  |  Quote  |  Print  |  Notify Moderator

ScottG wrote:

Huntingdog, I'm sorry but you're wrong on both counts.
Yes, it pushes the trailer back in line but there's nothing dangerous about it. I've even had it in the snow. Is the force "significant"? It is enough to do the job, nothing more. It is easily overcome when turning by the weights involved.
No, it does not use friction for control. It doesn't use brake material anywhere like other systems do. It uses pure spring pressure via the spring bars pocket climbing up off the cam. You could submerge the entire thing in oil and it would still work the same.

Best of luck to you.

Scott
For many years we had a resident engineer on the forum. His name was Ron Gratz. I believe he must have passed, as he no longer comes up in searches... Bad thing about this forum is that at some point a lot of old posts disappeared from the forum.
Too bad, as there was some great info lost forever.
Ron was legendary in being able to dissect precisely how hitches work.. And yes the DC vs EQUALIZER was analyzed by him. I won't attempt to quote him, as it was beyond me at the time, and my memory would miss some points anyway.. But I do remember for a fact that he stated both hitches were primarily friction based.
He even calculated the amount of friction for steel on steel.... Just because there is no "friction" material like brake pads does not mean there is no friction.

As for you saying that you have towed safely in slippery conditions, I believe you. But that just destroys your theory of the DC forcing a 5-10K 20-30' TT back to center.
The cams simply cannot produce that much force. And if they could. since it would be present at all times, then it would create problems in slippery conditions.

It is a friction based system with the cams along for the ride. It does make for great marketing for those that don't do an in depth analysis,,,,, and it is a fine system in it's own right... But just doesn't work the way some think it does.


LarryJM

NoVa

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Posted: 04/10/20 11:31pm Link  |  Quote  |  Print  |  Notify Moderator

ScottG wrote:


Well Larry, as a retired engineer I do understand how such things work and I can explain how lateral force is generated but I don't think you're open to a civil discussion about it. So, there's no reason for me to attempt to do so. We'll just have to agree to disagree.
One thing is for certain, there is absolutely no friction material employed in the DC.

Good luck to you.


Again IMO you clearly have demonstrated a true lack of understanding of these systems since the Equal-i-zer just like the DC Cam also has no friction material either. Both using the metal to metal friction with the DC Cam only using "sliding friction" whereas the Equal-i-zer uses both "rotational" friction from the sockets along with "sliding" friction from the bars in the "L" brackets.

Also anytime I see someone trying to use some vague education or experience credentials like your "retired engineer" reference often tells me one has no valid or verifiable position on a subject. While I could try and support my input on the subject being discussed here by saying I have and "actual" masters degree in engineering, but my degree is in "systems engineering" which has no real direct application to the topic of this thread so I don't go there. Thus, I quoted a real mechanical engineer that as Hunting has metioned has posted extensively on various mechanical based subject over a number of years and was a well known and I think respected source of actual factual knowledge of how things like these sway systems work in the real world.

With all that I think I have given anyone reading this thread a sufficiently based and referenced good source of information to support the position I have expressed here that the DC Cam system "NEITHER FORCES OR PUSHES" anything ... just like the Equal-i-zer system, it simply "resists" by friction sway movement of a trailer when towed.

Larry

Lynnmor

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Posted: 04/11/20 12:37am Link  |  Quote  |  Print  |  Notify Moderator

Huntindog wrote:





Since the friction bar can and should be adjusted, where did you get the "factory-set at 1100#" figure?

Just read the directions. The bar has a lever on one side and a bolt on the other. The lever is supposed to cranked down all the way every time. The bolt can be used to adjust it. The factory presets this bolt.

I know that many here adjust them with the lever, but the intructions specifically state not to.


My instructions do not mention that 1100# figure, but it does say to adjust. Yes, I know how to use it, just wondering where the 1100# came from.

Huntindog

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Posted: 04/11/20 04:37am Link  |  Quote  |  Print  |  Notify Moderator

Lynnmor wrote:

Huntindog wrote:





Since the friction bar can and should be adjusted, where did you get the "factory-set at 1100#" figure?

Just read the directions. The bar has a lever on one side and a bolt on the other. The lever is supposed to cranked down all the way every time. The bolt can be used to adjust it. The factory presets this bolt.

I know that many here adjust them with the lever, but the intructions specifically state not to.


My instructions do not mention that 1100# figure, but it does say to adjust. Yes, I know how to use it, just wondering where the 1100# came from.Mine said it could be adjusted if needed.
The 1100# figure came from Ron Gratz. He did the calculations, as per Larrys post which copied him.
The adjustment has limits,as those little balls and bar can only do so much.


Mike134

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Posted: 04/11/20 07:00am Link  |  Quote  |  Print  |  Notify Moderator

Here's something to visualize when you talk about hitches being able to "center" the trailer.

Picture the TV and TT on glare ice. Presume you have traction push on the trailer sideways at the far back end,(like the wind would) it's not difficult to sway the trailer sideways, now go to front and push on the A frame about 30" back from the hitch which is roughly where these "centering" hitches would act. It would take a huge amount of force with such little leverage to push the trailer back in line. Just my food for thought today

* This post was edited 04/11/20 08:17am by Mike134 *


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