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Discussion Starter #1
I’m wondering if a few of you guys with factory trailing arms can tell me if the tabs on the trailing arm where the swaybar link bolts to are straight up and down with the trailing arm or if they angle in slightly towards the motor.

I’m making new adjustable swaybar mount tabs and my tabs lean in towards the motor. I’m not sure if they’re bent in from use or if they’re welded that way. Just want to confirm how they should be before I make my new ones.

Thanks.
 

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Mine too. Im sure you noticed the ARB is narrower than then trailing arms. I wonder what is going on at the bar to address the angle there.

I suppose this also implies the inner is shorter by some small degree. Or the holes are oversize. Or..??
 

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Discussion Starter #6
ARB? The swaybar is narrower than the trailing arms. The holes in the tabs are not enlarged, the inner tab is shorter. I’m going to build a small jig for building the new mounts and will copy the angle that mine are at now.

I installed new swaybar bushings a couple days ago and the links bolted up at the correct angle with no stress so I assumed the tabs were designed that way, I just wanted to make sure.
 

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Howdy: ARB = Anti Roll Bar. A term used more often by the performance world.

You're off and running. Good for you! Thanks for being the next one up, and for sharing your learnings. I've no real metal shop and poor welding skills (newbie), so I'm going slower.

I've been trying to better understand why Glamisfan's sway bar worked to go stiffer. Looser? Easy to accept, for it's for sure exerting less, but I've been wondering if there was a reduction in the increase as a result of loss of angle.

However, I think I've been worrying about nothing. FYI, (altough you probably already knew this), the performance world seems to call this whole discussion the "Motion Ratio"

https://www.pro-touring.com/threads/40851-Motion-ratios-for-sway-bars

Good luck, let me know how it turns out!

-d
 

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Max:

What the heck do it know, right? So please feel free to conclude I'm wrong (as I often am). Still, I feel like that's (leverage) more correlation (and in reverse at that), than what's actually going on. And it depending on if we're talking about the bar or the arm. As one example, more leverage (longer)at the bar means less resistance, not more. On the trailing arm it reverses. So other then the reverse relationship at thy bar why isn't this a lever discussion?


Cause we're talking about two arms (ARB arm and the trailing arm), of very different lengths, and different radius's. It's the radius that makes it interesting, for it's not leverage per say, but rate. The "amount" the sway bar is asked to move in relationship to the movement of the trailing arm. (driven by the radius differences!)

What distracted me was the thought that these two arms are connected by a link that swivels at each end. However, short of mount deflection I've realized the rate of rise of one bar, regardless of it's angularity of connection to the second, will increase as the travel of the first bar increases (although it may be affected to some small degree by angle change). Somebody better at geometry than I am could probably calculate the relationship, but it's for sure not leverage. Again, it's a direct result of changing the rate of rise of one bar vs the other. Faster means more resistance, slower means less. Which is why moving the bottom link in towards it's center (radius root) give a reduced rate, while moving it out increases rate. Not more leverage, more motion relative to the ARB.

Lotta similarity though, and there is a lever relationship, but it's rate of motion driven by radius not length of arm giving more force (leverage).

All of which is probably why they call it the motion rate. Not that I know, I'm justed wanted to understand it.


Hope I didn't sound argumentative.

atb,

-d
 

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Way over thinking. Really has nothing to do with the trailing arms. Given identical mounting locations on the trailing arms and the same length sway bar links only sway bar stiffness and link location on the sway bar affects amount of body roll. The further out from the sway bar pivot location the greater the force the trailing applies upon the sway bar. This will allow more body roll. Closer to the pivot location results in less force, a tighter setup, and less body roll. Less body roll equates to less articulation and vice versa. For the most part less articulation is not desirable in an off road machine unless most of the driving is high speed flat terrain.

OP, what are you trying to accomplish? Moving the mounting location on the trailing arms will have little effect. To change the sway bar rate effectively the link location on the sway bar needs to be changed. If the idea is to make it stiffer you need to upgrade the links. The stock ones are barely adequate and regularly fail. Something like:
 

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Discussion Starter #11
Another member made new tabs on the trailing arm further forward than the originals and said it improved the ride. I want to get Walker Links this spring but I want to try new mounts first because A: It’s free, and B: I can fabricate. I have Rocky Ready gussets I need to weld on so I figured I’d build the new swaybar tabs at the same time.

My plan was to make new swaybar links out of some bent oem radius rods I have. Both of the following pics are screen shots of what I want to do. Except I was going to weld much shorter tabs with only 3 holes total allowing me to move the link 1” or 2” further forward from the oem position. The second pic are the links I’m going to build out of the radius rods.
 

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He’s expecting to change the motion ratio by moving the link mounting points on the trailing arm. Which as I show above should be effective. And has already been proven by another member. Is this all smoke and mirrors? Maybe, but the science supports his plan. I’m certainly following with interest, and will probably even measure the motion ratio changes before i start cutting and welding.

All the best,

-d
 

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He’s expecting to change the motion ratio by moving the link mounting points on the trailing arm. Which as I show above should be effective. And has already been proven by another member. Is this all smoke and mirrors? Maybe, but the science supports his plan. I’m certainly following with interest, and will probably even measure the motion ratio changes before i start cutting and welding.

All the best,

-d
That's not gong to do much of anything as I explained above let alone improve the ride but whatever floats da boat.
 

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Another member made new tabs on the trailing arm further forward than the originals and said it improved the ride. I want to get Walker Links this spring but I want to try new mounts first because A: It’s free, and B: I can fabricate. I have Rocky Ready gussets I need to weld on so I figured I’d build the new swaybar tabs at the same time.

My plan was to make new swaybar links out of some bent oem radius rods I have. Both of the following pics are screen shots of what I want to do. Except I was going to weld much shorter tabs with only 3 holes total allowing me to move the link 1” or 2” further forward from the oem position. The second pic are the links I’m going to build out of the radius rods.
It's cool you're thinking outside the box and you want to tinker, just don't expect it to change much of anything.
 

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Moving the location of the sway bar link mounts on the sway bar or on the suspension arm will change the roll stiffness.

Moving the sway bar link mount (on the sway bar) toward the sway bar pivot and shortening the sway bar arm will stiffen the sway bar and reduce body roll. The opposite is true, where lengthening the sway bar arm will soften the sway bar and increase body roll.

Moving the sway bar link mount (on the suspension arm) toward the suspension arm pivot will soften the sway bar and increase body roll. Here again, the opposite is true, where moving the sway bar link mount away from the pivot will stiffen the sway bar and reduce body roll. This is a function of the motion ration and applies to any suspension arm, whether it is a trailing arm or A-Arm.

In short, since we are talking about the rear trailing arms on a RZR:
Forward = Softer sway bar / More body roll
Rearward = Stiffer sway bar / Less body roll
 

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Thunderhawk:
Thanks for the insights. I'm certainly hopeful! Heck, I'm thinking about how this might be carried over to the front (with no success).

Snowmble:
Any progress? I'm in Illinois and so even though I'll do mine soon, I won't have any feedback until next spring. Probably.

All:
Snow is, I think, moving to a softer setting while I'll be moving to harder and using a quick disconnect for the occasional times independent wheel travel really means something to me. I'm curious. Does anybody think a the way bar mounts take a side load for some reason? Said another way, would a 3/8" trailer safety pin with a layer of shrink tube for anti-rattle work?

Before you think I'm nuts, here's an example of Rough Country making a quick disconnect for a Jeep using them:
https://www.amazon.com/Rough-Country-Disconnects-compatible-1188/dp/B00CUOLQUC/ref=asc_df_B00CUOLQUC/?tag=bingshoppinga-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4584138860136775&psc=1

We however, since we're using a10mm bolt, might be able to just replace the drivers side bolt and carry on. (Or not)

??

Thanks to all

-d
 

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Well that didn't take long. DoubleD Racing, ProUTV, and ZBroz, at the very least, are all selling the exact same sway bar quick disconnect. And it's certainly not threaded. Although it may be a width specific.

https://www.proutvparts.com/collections/suspension/products/rzr-xp-1000-rzr-xp-turbo-rzr-rs1-quick-disconnect-pull-pins-for-sway-bar-kit

And then there's this:
https://forum.ih8mud.com/threads/front-anti-sway-bar-quick-disconnect-solution.815899/

huh. I guess worth trying out. O-ring on the end's not a bad idea either.
 

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I'm thinking about how this might be carried over to the front (with no success).
The principal is the same, the execution is more difficult. The sway bar link mount would need to move front-to-rear or the A-arm link mount would need to move in-or-out. Then you'd need to verify clearances throughout the full suspension travel.
 

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Snowmble:

Math looking this over:

Unless I've made a major math mistake, RzrJoe has a case to be made. Moving the connecting point at the swingarm small amounts doesn't amount to much in our case. That fly's in the face of what Glamisfan reports, and in what I've seen on "motion ratio".

For Glamisfan I can only suggest either my math is wrong or he can detect pretty small changes. As to motion ratio it still applies, but our trailing arm pivot radius is so much longer than our sway bar pivot point that the relationships are altered. As in the change in pivot points become larger than one might have expected.

I get a sway bar radius at the standard connector (center to center) location of 6.765". That's equal to .118" of travel per degree of rotation (circumference divided by 360), and the degrees of arc traveled per inch is 8.4694 degree's (1/.118"). (6.765 x 2 is diameter, times pi (3.14159) is circumference).

Moving the link connecter in (forward), or shorter one inch (if we could), on the sway bar brings the degrees of arc at once inch of lift to 9.9385 degree's of arc for the "tighter setting" arc.
((6.765" - 1") X 2 X 3.14159/360 = .1006) and 1/.1006=9.99385)

Moving back to the standard location and dividing 9.9385 by 8.4694 (the standard locations degree of arc per inch) tells us we'd have to lift 1.17" instead of 1" to get an equal amount of sway bar force (degree's of rotation) the "tighter setting" of -1 inch at the sway bar delivered.

(Sanity check. Does a 17% increase in stiffness seam like 1" shorter on the sway bar? Yep, I think so too)

Fair enough, we just need to lift more per inch at the trailing arm by .1734" per inch. We knew something like this was coming all along. Measuring the trailing arm center to center radius I get 49cm, or 19.291". That's .3367" of lift per degree of arc, or 2.9701 degrees of arc per 1" of lift. (19.291 * 2 * 3.14159 / 360=.3367" of lift per degree or arc. And 1/.3367= 2.9701 degrees of lift per inch)

Adding the needed .1734 inch of lift for equivalence to "-1" a the sway bar" means we need 1.1734" of lift per 2.9701 degree's of arc. (1/2.9701*1.1734") degree of arc at the swingarm or .3951" of lift per degree of arc.

.3951"*360/3.14159/2 = 22.6372'" of radius, or around 3.34" farther back than the existing location. That looks like a lot. It's possible, but it's over three times the change relative to the sway bar....

Damn! Glamis reported it cornered like it was on rails at 2" back. I'm amazed he could tell with what must be a single digit increase in stiffness at 2".
 
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