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Old 04-06-2019, 10:55 PM   #5601
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Originally Posted by arcaguy View Post
Absolutely nothing useful.

Really dude, everything you spouted has been addressed and debunked repeatedly in this thread already. I'm sorry that you're confused, but the point of the CHF does actually matter, and it does make a difference.

Your z bracket comment is a head scratcher, though. Do you know what it even looks like or what is being discussed?
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Old 04-06-2019, 11:12 PM   #5602
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Here we go again.....

ARCA, at the risk of boring everyone to death, I’ll just make a couple quick points:
1. Relocating the link to the inner hole reduces the leverage the coach has on the bar and thus increases the force necessary to twist the bar, hence increasing the effect without increasing the dia of the bar. Simple physics
2. There are two basic methods - using stock links and rotating the SB upwards to make them fit, or fabricating longer links for the front or buying adjustable links such as Hellwig 7962 thus keeping the SB level and using the front links in the back since they are conveniently the correct length to maintain factory geometry

Im in favor of the second choice for several reasons Ive already explained, but wont dispute the success of many here who have chosen the first method.

But I think the most important thing is to address angular momentum by examining the extinction angles and the rate of decline of the obliquity of the ecliptic - then it all becomes perfectly clear.
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Old 04-07-2019, 06:07 AM   #5603
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arcaguy,

The ends of the bar, turned 90°, are the levers used to twist it.

Shorter levers require more force to twist the bar. That's why you don't try to remove lug nuts with a 1/4" ratchet.

Maybe a picture will help.

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Old 04-07-2019, 01:07 PM   #5604
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There's different ways of looking at what happens. I prefer to not say softer or harder (stiffer). In reality it's the same except softer and harder conveys a different thinking.

I prefer to use exactly how a levers length effects what it's supposed to accomplish. The longer the lever the greater the mechanical advantage.

If you hit a bump with a tire which imparts 100 lbs of force when attached to the outer hole the SB moves a given amount. Lets just say for discussion it twists the SB 2".

Now employ the CHF and hit the exact same bump. The 100 lbs only moves the SB 1". It has lost mechanical advantage so the SB twists less. The 100 lb force with a shorter lever still imparts 100 lbs of force but twists the lever less. It's not because anything got stiffer or harder it just moves less. The end result is the 100 lbs force with the CHF reduced the RV's SWAY by 1/2.

"Shorter levers require more force to twist the bar."

I believe it is slightly misleading to state the above. Shorter levers don't require more force to twist the SB they just move less when the same force is applied. We are looking for a result which is less SWAY. A stabilizer bar controls SWAY by using a shorter lever so the SWAY is reduced when the same force is applied.
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Old 04-07-2019, 01:16 PM   #5605
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Quote:
Originally Posted by TeJay View Post
There's different ways of looking at what happens. I prefer to not say softer or harder (stiffer). In reality it's the same except softer and harder conveys a different thinking.

I prefer to use exactly how a levers length effects what it's supposed to accomplish. The longer the lever the greater the mechanical advantage.

If you hit a bump with a tire which imparts 100 lbs of force when attached to the outer hole the SB moves a given amount. Lets just say for discussion it twists the SB 2".

Now employ the CHF and hit the exact same bump. The 100 lbs only moves the SB 1". It has lost mechanical advantage so the SB twists less. The 100 lb force with a shorter lever still imparts 100 lbs of force but twists the lever less. It's not because anything got stiffer or harder it just moves less. The end result is the 100 lbs force with the CHF reduced the RV's SWAY by 1/2.

"Shorter levers require more force to twist the bar. That's why you don't try to remove lug nuts with a 1/4" ratchet."

I believe it is slightly misleading to state the above. Shorter levers don't require more force to twist the SB they just move less with the same force. We are looking for a net result. That's how a SB controls SWAY. It uses a shorter lever so the SWAY is reduced when the same force is applied.
Its movement, not force. A shorter lever moving 2" will attempt to twist the bar more. The bar resists, limiting the sway.


The statement you just made, below, is completely opposite of how it works.


If you hit a bump with a tire which imparts 100 lbs of force when attached to the outer hole the SB moves a given amount. Lets just say for discussion it twists the SB 2".

Now employ the CHF and hit the exact same bump. The 100 lbs only moves the SB 1". It has lost mechanical advantage so the SB twists less. The 100 lb force with a shorter lever still imparts 100 lbs of force but twists the lever less. It's not because anything got stiffer or harder it just moves less. The end result is the 100 lbs force with the CHF reduced the RV's SWAY by 1/2.
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Old 04-07-2019, 05:44 PM   #5606
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First of all in my example the shorter bar won't move the SWAY bar 2". It can't because there's not enough leverage and that's why it works to control sway. The 100 lbs can only move the SB so far.

Don't confuse the issue. We all know how this works.
Please explain how 100 lbs of force on a shorter lever attempts or tries to move the lever MORE???? 100 lbs is 100 lbs and nothing more or less. It's still 100 lbs.

Maybe in your world your SB works different than mine. "The 100 lb force with a shorter lever still imparts 100 lbs of force but twists the lever less." That results in SWAY control. That's a SWAY bar. That's how they work in my world!!!

A movement is created by a force what the heck is the difference? Something can't move if there's no force or energy making it move.
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Old 04-07-2019, 06:18 PM   #5607
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Ok lets all get on the same page and separate the apples from oranges (at the risk of mixing some metaphors....).

The lever is the short end(s) of the sway-bar (SB) with the the two holes in it. The links just push on the lever, regardless of where they are mounted.

However, the closer the links are mounted to the axle (i.e.: the inside hole on the SB), the less leverage they will have because the “lever” (which is the short end of the sb with the holes) is shorter. So the long axis torsional portion of the SB will exert more resistive force on the chassis thus limiting “sway”.

Can we all agree to that? If so we can sort out this discussion and probably realize everyone is talking about the same thing.

JM must be loving this....

On another note, unless anyone wants these (rear links) they will end up relegated to the parts pile in my attic along with all my spare chrome moly tubing....
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Old 04-07-2019, 06:42 PM   #5608
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I agree with the above post.

TeJay, if you used a short 100 lb torque wrench, and a long 100 lb torque wrench, which one would be harder to get to 100 ft lbs.

The handle on the longer one would travel more but be easier to push.

The sway bar sits clamped to the axle. The links are pushing and pulling the levers, twisting the horizontal bar, as the chassis leans side to side. Shorter levers = more force to twist.
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Old 04-07-2019, 07:50 PM   #5609
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Quote:
Originally Posted by TeJay View Post
There's different ways of looking at what happens. I prefer to not say softer or harder (stiffer). In reality it's the same except softer and harder conveys a different thinking.
Reducing leverage on a torsion spring increases spring rate. When you increase spring rate the spring becomes harder / stiffer, when you reduce it it becomes softer. Theses are the words used in the English language to describe the difference between springs. This spring is softer than that spring etc. the English units used to describe how stiff a spring is are lbs force per inch of compression:


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Stock front sway bar on a F53 is 750 lbs per inch of spring rate or stiffness, standard CHF is 1250 lbs per inch, extending the links to create a 90 degrees angle with the CHF softens the spring to 1000 lbs per inch. Angle is always part of the equation when calculating leverage, this is basic physics.

The following image comes from from a suspension tuning book from the 1970's, the A value changes based on angle the C value does not:

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The physics and terms were well understood more than 50 years ago, to be arguing that a sway bar is 1: not a spring, 2: that the CHF does not make that spring it stiffer is a real shame in 2019 and honestly a waste of time. In automotive circles this is not debated, the CHF is not some magic change, its simply referred to as "adjusting your sway bar". You make it stiffer to reduces sway, you make it softer to be less harsh over uneven bumps. You trade sway for softness to your liking just like adjusting any spring in your suspension, the sway bar just engages under more specific circumstance then the main springs.

My Jeep has a great feature where I can hit a button and disengaged the front sway bar, man is it nice and soft up front when I do so, just floats over bumps, but it re-engages automatically at 18mph because if you take a high speed turn with it disengaged you will dive and might even roll the Jeep:

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Its just has a splined coupler that a motor slides back and forth to connect the two halves of the sway bar.

Quote:
Originally Posted by TeJay View Post
I believe it is slightly misleading to state the above. Shorter levers don't require more force to twist the SB they just move less when the same force is applied. We are looking for a result which is less SWAY. A stabilizer bar controls SWAY by using a shorter lever so the SWAY is reduced when the same force is applied.
They require more force for the same compression, hence the units lbs force per inch compression that all springs are measured in. The same force will compress a stiffer spring less than a softer spring. You are the one attempting to mislead by mincing words, I am not sure what your goal is but it is not helping the discussion, lets accept automotive terminology established long ago and move on.
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Old 04-07-2019, 08:24 PM   #5610
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Originally Posted by R.Wold View Post
JM must be loving this....
He is still here and reads the threads sometimes, maybe he will chime in if he feels like it, but I think he feels its a lost cause.

Not sure why I persist at this point, I just want people to have correct facts and not base their decision on superstition and pseudo-science. The more than 100 years of automotive engineering and much more of physics is out there for anyone to read for themselves, just trying to direct those to it in summary form.
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Old 04-07-2019, 10:40 PM   #5611
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jharrell,

I have NEVER said that a SB is not a SPRING. I know it is a TORSION spring. What you are saying is when a lever is shortened the spring gets stiffer. Move the hole towards the pivot point and the spring gets stiffer.

In effect yes it gets stiffer but it does not magically change its metallurgical make up to a stiffer spring. The net result of a shorter lever is better SWAY control. I've always understood it but I still believe when you say the spring gets stiffer it is misleading.

I agree with what you are saying but you all still insist on saying the spring gets stiffer. It gets stiffer because of the shorter lever. Call it a different "Spring Rate". If that's the correct engineering term fine. To explain that to HS students in your terms would be confusing. IMHO!

You do need to understand that HS counselors used almost every automotive program as a dumping ground for students not aspiring to a college degree. We all fought that game our entire careers. Our students didn't take physics, Trig, or Calculus.
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Old 04-07-2019, 11:02 PM   #5612
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The shorter lever doesn't make the torsion bar stiffer.

The shorter lever attempts to twist the torsion bar further when the RV leans.

Twisting it more makes the torsion bar get stiffer.

It fights the twist sooner, limiting the sway.

Second part.
When one wheel hits a bump, that spring compresses. That causes the link to push the lever down. ( axle goes up )

With the stiffer reacting sway bar, it will cause the opposite side to try to pull that side of the axle up against that spring, even though it didn't hit the bump. That causes the harsher ride.
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Old 04-08-2019, 07:06 AM   #5613
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I have NEVER said that a SB is not a SPRING. I know it is a TORSION spring. What you are saying is when a lever is shortened the spring gets stiffer. Move the hole towards the pivot point and the spring gets stiffer.
Sorry its hard to keep it straight at this point, I have heard so many round about explanations trying to avoid the obvious because people want things to work a certain way even if they don't. I am just trying to make it clear, a sway bar is just a helper spring who's stiffness can be adjusted by changing the link attachment point and that is attached to the axle in such a way that it only engages under the right conditions rather than all the time like a normal helper spring.

Quote:
Originally Posted by TeJay View Post
In effect yes it gets stiffer but it does not magically change its metallurgical make up to a stiffer spring. The net result of a shorter lever is better SWAY control. I've always understood it but I still believe when you say the spring gets stiffer it is misleading.
You are the one misleading by trying to say the stiffness of a spring is only a function of its metallurgical properties. That is only one variable in the makeup of a spring. The type of metal, the diameter, the shape, whether its hollow or solid, the length and in the case of a torsion spring the lever length all work together to make THE SPRING. A torsion spring is not a spring without a way to twist it, without the lever its just a steel bar.

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Originally Posted by TeJay View Post
I agree with what you are saying but you all still insist on saying the spring gets stiffer. It gets stiffer because of the shorter lever. Call it a different "Spring Rate". If that's the correct engineering term fine. To explain that to HS students in your terms would be confusing. IMHO!

You do need to understand that HS counselors used almost every automotive program as a dumping ground for students not aspiring to a college degree. We all fought that game our entire careers. Our students didn't take physics, Trig, or Calculus.
I think it would be very confusing for my HS teacher to not refer to adjusting the sway bar as making it stiffer or softer, just like you would say I am going to put stiffer springs on this car because the current ones are too soft. No only are those terms accurate they also intuitively convey what its doing to the suspension.

If someone where interested in going beyond that you can get into the trig of the lever arm, but you don't need to know that all you need to know is moving the link to a hole closer to the bar makes it stiffer, move it out makes it softer, no need to try and twist words around for what purpose?

Did you teach HS school kids how to use a torque wrench? Did they understand the foot pounds units of torque? Did they understand that a higher ft-lbs number meant more torque and therefor a tighter nut? If they can understand that there is no reason they can understand spring rate in the very similar inch-pounds and that a higher number means a stiffer spring and a lower one means softer. Why confuse things with any other word play, that would be a disservice and more confusing IMO.
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Old 04-08-2019, 07:21 AM   #5614
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With the stiffer reacting sway bar, it will cause the opposite side to try to pull that side of the axle up against that spring, even though it didn't hit the bump. That causes the harsher ride.
I have tried explaining this and seems to be the reason Tejay wants to avoid using the terms soft/hard/stiff for a sway bar because he doesn't believe it makes for a harsher ride.

One of the better explainations is here:https://mechanics.stackexchange.com/a/27816

I have posted before but doesn't seem to get through, this picture explains it perfectly:

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Since motohomes are top heavy and mostly drive on level roads more sway control through a stiffer set of sway bars is preferred but you will get more harshness going over a pot hole on one side, whether it bothers you or the trade off compared to the lack of sway is a personal preference. If you understand that you wont be confused as to what happens when you do the CHF or other spring additions/adjustments.
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