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now here are some pics from last weekend that just shows (1st ones) the links mounted real high above the axel and still the brackets are on the thin side but work very well from the next pic.
 

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This is the above vehicle and it seamed to flex out real nice but I have no idea how it is on the street or more than a crawl off road!
 

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Now here is a side shot of Mike's rig and you can see it is completly wronge according to petersons! But works very well as we all know. And if you don't know just read the above line because I just told you it did:D
 

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And the full shot of Mike's rig. What this shows is their is a lot of ways to set up links to work in the rocks but what I think this thread is about is the full package. Street, desert hight speed and of course ROCK CRAWLING! So as I am still doing, read alot and ask questions. As I found it is more help to have a pic (cad or pencil ) to show and get feed back off of.
 

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SWEET

now i understand what effects moving stuff around has but i still dont understand why.

how is changing the uppers going to effect a rig?

lets say the uppers are flat and the lowers are angled up like 5-10 deg.

lets also just say that the rig works good with it setup like this.(i have no idea if it would or not)

how and why will moving the uppers to angle down a tad change the rigs performance?

if you can answer this completely you will soon become a suspension pimp. after my next??:D
 

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71RCKCRZR RYAN said:
SWEET

now i understand what effects moving stuff around has but i still dont understand why.

how is changing the uppers going to effect a rig?

lets say the uppers are flat and the lowers are angled up like 5-10 deg.

lets also just say that the rig works good with it setup like this.(i have no idea if it would or not)

how and why will moving the uppers to angle down a tad change the rigs performance?

if you can answer this completely you will soon become a suspension pimp. after my next??:D
you need to go back and reread, already been ask and answered.
 

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I would love to be a pimp so let me try and dazzil you with bull shit. How I see it is if you draw a line through the center's of your upper links and extend this line forward. Then do the same for the lower links they should cross each other at some piont forward of the link /frame attachment. Now this part is hard for me to explain but were this convergance piont is will affect the push of the vehical. For instance the higher it is the vehicals power will push along this line and push the vehical the same direction, so if it is at a 45* angle the rear of the vehical will lift tons. If the convergance piont of the extended line of the links is real low to the gound it will push the rear end in to the dirt. So what you want is sort of straite forward to push the vehical straite forward with out the ill efects of squate or lift. Now tell me if this made any sence and more importantly if it is any were near being right?
 

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Changing the uppers (or lowers) changes the roll characteristics (roll axis, roll center) and the location of the instant center.

The roll characteristics determine how the vehicle will handle in corners and side hills.

The location of the instant center is what determines the squat or anti-squat behavior of the rear end.

The instant center is the intersection of lines drawn through the top and bottom links as viewed from the side.

This picture was posted before, but I'll post it again because it is a very good illustration of instant center and squat/anti-squat.

Roll and squat characteristics are both directly related to the center of gravity (COG or CG) of the vehicle.
 

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That looks just like the pic in my mind!! Come on in a take a peak!:confused:
 

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Now to determan your CG I have read that if you don't know were it is just use the top bolt of your bell housing. Is this close or is their a nother way? I tryed to find it by tipping my new rig over but I just keep getting paper cuts..
 

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.........thnx fellas.........

k...........i understand where the instant center is
i understand roll center

so ic is where the push is applied??

what is the line going from the bottom of the rear tire o the front of the car???
 

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Well it seams this is used along with the link convergance piont to determain anti squat. Once you know were your center of gravity is along with your link center piont convergance you then draw a line from the rear contact patch of the tire to the link convergance piont. This line should cross the vertical line of the front tire and be between 50% and 80% ot the center of gravity line and the ground. This is a good place to start according to the mag write up. If you look at my bad drawings you will see alot of adjustment built into the rear uppers. This is to alow adjustment to find the sweet spot for anti squat. Hope this helps. If not let me know and I wll delete it:p
 

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Yes, IC is where the push is applied.

The line going from the tire contact patch to the height of the COG over the front axle is the line that if you IC is above, you have anti-squat, and if its below, you have squat. I don't think there is a name for it.

The thing I DONT understand about that line is why its not drawn straight to the COG. Maybe one of the engineering/link gurus can explain that... :confused:

The way they show it, the squat characteristics are dependant on wheel base and you could move the COG forward or backward and theoretically it would have no affect... which I know can't be the case.
 

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I think they are using the CG as a horizontal line and not the vert line shown above. So if this is the case it is drawn to the piont of link convergance and the piont it crosses through the front tire center line is the % of interest. So yes if you have a longer WB you would need flatter links to achive the same Anti squat a short WB vehical with steeper links would need. This shoud make sence since the handling is directly related to size of the vehical is it not. I will check back at 4am when I get up.
 

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rokcrln said:
Well it seams this is used along with the link convergance piont to determain anti squat. Once you know were your center of gravity is along with your link center piont convergance you then draw a line from the rear contact patch of the tire to the link convergance piont. This line should cross the vertical line of the front tire and be between 50% and 80% ot the center of gravity line and the ground. This is a good place to start according to the mag write up. If you look at my bad drawings you will see alot of adjustment built into the rear uppers. This is to alow adjustment to find the sweet spot for anti squat. Hope this helps. If not let me know and I wll delete it:p
The link convergence point (LCP, the mag call it the "Lateral constraint or control point) doesn't have anything to do w/ squat, only roll axis. If you look at their picture, the LCP, it is behind the front axle, but the IC is in front of it.

The line drawn through the two LCP's is the roll axis.

This is all for double-triangulated links that are not parallel when viewed from the side.

For single-triangulated links (uppers or lowers are parallel when viewed from top), the roll axis (viewed from the side) goes through the single LCP and is parallel w/ the lower links.

For double-triangulated links, the roll axis is the line drawn between the two LCP's.

For links that are parallel when viewed from the side, the IC is an infinite distance in front of the vehicle. (I'm not sure exactly how you figure out the squat for this situation, but I think it has to do with the angle of the links compared to the angle of the line drawn from the tire contact patch to the COG :confused: )

For links that are not parallel when viewed from the side, the IC is where lines drawn through the links converge and you figure out the squat as shown in that black & white pic I posted a couple of posts up.
 

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i've learned alot from this thread... thanx guys

i've just got a thought in my head and wanted some feed back....before you shoot it down too quick, try to think what would ahve to happen to make it work.....then you can bash hte hell out of it.

In an effort to try to keep the bars away from the rocks......what would the effects be if you mounted the lower links towards the center of the axle then "V" up to the frame... AND...mount the upper links on the outside of the axle and up towards the TC....

in a nut shell it would be the typical double triangled setup just with the upper and lower links switched


Weston
 

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That would give you a really steep roll axis. Lots of rear-steer (axle steer).

Usually you want to shoot for a flat RA to reduce or eliminate rear steer.
 

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Check out TEAM PURPLE on this pbb he is set this way front and rear. Seems to work for him for trail only.
 

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ErikB said:
Yes, IC is where the push is applied.

The line going from the tire contact patch to the height of the COG over the front axle is the line that if you IC is above, you have anti-squat, and if its below, you have squat. I don't think there is a name for it.

The thing I DONT understand about that line is why its not drawn straight to the COG. Maybe one of the engineering/link gurus can explain that... :confused:

The way they show it, the squat characteristics are dependant on wheel base and you could move the COG forward or backward and theoretically it would have no affect... which I know can't be the case.
This is the reason why the line isnt through the COG.

Now again this would be easier with a picture but I will try to explain it without.

Now when the rig acceletates we get a horizontal inertia force from the COG pushing backwards.

In the 100% AS case the force from the tyre acts through the IC of the rear links. Now this line passes through the 100% AS and the line is the direction of the resultant force from the tyre (this is comprised of the horizontal driving force - Fh and the ground reaction force - Fv .... (this force comes about because the driving force must be transfered by the links through the IC which is upwards at an angle and thus it creates a force at right angles to the ground)

Now the drag force from the COG is the same as the drive force Fh.

So the for the rig to not squat (or anti squat) the rotational effect from the COG force must be the same as the rotational effect from the ground reaction force - Fv.

So if we compare these rotational forces in relation to the front tyre contact point (so that we dont have to worry about the front forces) we get an equation -

COG force x COG vertical height = rear ground reaction force x wheelbase.

now COG force = Fh
and ground reaction force = Fv

so that means

Fh x COG vertical height = Fv x WB

this means that Fh/Fv = WB/COG vertical height

So that for a 100% AS the ratio of the vertical and horizontal forces at the rear tyre is the same as the ratio of the height of the COG and the wheelbase.

Now drawing the height of the COG at the front axle is just a easy way to graphically represent and compare these two ratios.

Clear as mud??

Sam
 
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