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Narrowed rear control arms

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Jeff,

If you attach the inner links at the crossmember stacked vertical rather than in the same horizontal plane, it will effectively locate the pivot point forward of the physical mounting location.

 

By doing this you can reduce the amount of toe and camber change as the suspension travels thru it's range of motion.

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Dave,

We looked at doing just that. The problem is it necessitates a complicated mounting block or cutting and welding on new pivot points.
We wanted it to be more "bolt-in" this time around which is what the axial pivot points provides. We decided if we were going to go that far we would just make a new crossmember and put all the points wherever we wanted, maybe next time.

As far as camber and toe, we're able to change the progressions by moving the mounting points on the trailing arm since that is free for us to change. It's not as effective as moving the inner pivots but it lets the kit remain "bolt-in."

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More updates!!  I'm sure some of you guys got to see this at Canby, but for those who didn't!  We also test fitted the arm today.  It worked out better than we expected, it will require cutting out the nub off for center the stock spring.  Which we didn't care to much about.  as of now it almost goes as low as the stock arm.  Maybe an 1" off.  With a slight design change we should be able to get where we want to be.  Now for the pics.   O and this is a 14x8 -6 Star shark wheel (my favorite JDM wheels so we had to borrow one from Dillon for test fitting.  

 

1Sz6LwS.jpg

 

 

 

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You put those heims in the position you told me they shouldn't be used :P

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You put those heims in the position you told me they shouldn't be used :P

 

 

I didn't Sam did :)   I worried more when it was a sheet metal arm, if the length is changed on a 100% sheet metal arm the distance can't change and they are binding.  

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There is your proof ladies and gentlemen, the wolfman doesn't sleep and runs on coke.

 

Arms look good man, keep it up!

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Are we viewing the bottom of the x-member and arm in these picts?

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Looks like the first one is right side up and the installed pics are on an upside down car. :lol: 

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I got to admire this set up at Canby. Looks great in person guys. Saving my pennies!

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I have seen a few of these designs. 

 

I had a similar one drawn up but I made the sheet metal arm come from the inner mount and the turnbuckle links mount to the outer shear flanges. 

 

Ac2T4Rk.jpg

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Been a while since we updated.  As per normal we've changed the design a few times, Sam is a picky bastard....  My response is usually "But I just want to drive my car!!!"   Well here is what we have now...  The version above didn't allow us to change the suspension characteristics like we wanted.We decided to use the inner pivot which makes it more of an "A" arm.  Plus we ditched the odd loaded heim joint for a weld in spherical bearing.  Next we are going to run it through FEA and weld up a prototype.  Who knows when we will have a set in my car or be able to sell any.  

 

VOmQyJx.jpg

 

 

 

 

xwfuSD1.jpg

 

 

 

 

 

 

 

 

 

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Dude, I like the stabilizing arms being attached to the mustache bar. Much more stable. Having a shallow triangle by attaching the trailing arms to the inside pickup point on the cross member does give wide open space for a massive rear tire, but why not have a large notch setback in the arm attached to the outside pickup for a broader triangle and greater strength?

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My mind is blown with those 3d modeling skills... dang

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Cool work!! 

 

I told you the inner mount was good ;)

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Been a while since we updated. As per normal we've changed the design a few times, Sam is a picky bastard.... My response is usually "But I just want to drive my car!!!" Well here is what we have now... The version above didn't allow us to change the suspension characteristics like we wanted.We decided to use the inner pivot which makes it more of an "A" arm. Plus we ditched the odd loaded heim joint for a weld in spherical bearing. Next we are going to run it through FEA and weld up a prototype. Who knows when we will have a set in my car or be able to sell any.

 

VOmQyJx.jpg

 

 

 

 

 

If you use the outer mounting point this would be a copy (in function) of a common and proven design and woud have less toe change under deflection.

Not saying your's wont work good. Love your skills.

 

 

Edit:

Looking at it more if the hub carrier is rigid to the forward arm it's going have a camber arch like a swing axle and will bind with the two track bars.

 

One track bar would work but the camber change would be a problem

 

If the two rear track bars are to control the camber the forward mount will need to be outward

 

Sorry for being a nerd

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What is going to stop the wheel from moving front to back?

 

I would think using your first a-arm design, but with the diff mounted adjustment rods would be good, but as stated above, I dont think camber will be able to adjust/compensate/move, with up and down travel, as shown.

 

Unless the outer rod mounts were also both able to pivot as one, as the suspension travels.

 

The whole hub needs to be able to pivot, not be welded as one with the main a arm.

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Dude, I like the stabilizing arms being attached to the mustache bar. Much more stable. Having a shallow triangle by attaching the trailing arms to the inside pickup point on the cross member does give wide open space for a massive rear tire, but why not have a large notch setback in the arm attached to the outside pickup for a broader triangle and greater strength?

 

 

We modeled it that way at first.  To make it work without limiting clearance it ends up being a "Z" arm and looks dumb and weak.  Here is a picture.   

 

 

kaSxbSE.jpg

 

 

My mind is blown with those 3d modeling skills... dang

 

Sam gets it done!  I help where I can.  Assemblies go over my head. 

 

 

 

Cool work!! 

 

I told you the inner mount was good ;)

 

:) 

 

 

If you use the outer mounting point this would be a copy (in function) of a common and proven design and woud have less toe change under deflection.

Not saying your's wont work good. Love your skills.

 

 

Edit:

Looking at it more if the hub carrier is rigid to the forward arm it's going have a camber arch like a swing axle and will bind with the two track bars.

 

One track bar would work but the camber change would be a problem

 

If the two rear track bars are to control the camber the forward mount will need to be outward

 

Sorry for being a nerd

 

 

 

It's not rigid it's a spherical bearing.  

 

 

 

qQF6Yfu.jpg

 

 

 

 

What is going to stop the wheel from moving front to back?

 

I would think using your first a-arm design, but with the diff mounted adjustment rods would be good, but as stated above, I dont think camber will be able to adjust/compensate/move, with up and down travel, as shown.

 

Unless the outer rod mounts were also both able to pivot as one, as the suspension travels.

 

The whole hub needs to be able to pivot, not be welded as one with the main a arm.

 

 

It works we can post camber and toe progressions.  The main arm is on a spherical bearing which allows it to twist and move anywhere it wants.  The 2 "race rods" (making a total of 3 points, which define a plane) then capture it and allow us to adjust the toe and camber curve.  

 

Hopefully this helps you see how it works.  

 

SolidWorks would be the first to let us know it won't work.  Trust us there! 

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"It's not rigid it's a spherical bearing."

 

It's the outer hub end of the arm I was referring to. The version with the "Z" arm would function the same as a E36.

I'm not grasping how the current design will allow the race rods to not bind with the ark of the forward arm. The forward arm will no longer travel the path of a trailing arm but act like a swing axle. Yes, No?

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"It's not rigid it's a spherical bearing."

 

It's the outer hub end of the arm I was referring to. The version with the "Z" arm would function the same as a E36.

I'm not grasping how the current design will allow the race rods to not bind with the ark of the forward arm. The forward arm will no longer travel the path of a trailing arm but act like a swing axle. Yes, No?

 

Whether attached to the inner or outer point the degrees of freedom are controlled in exactly the same way.

A swing axle is mounted with axial rotation only, just like a trailing arm. This constrains rotation in the camber/toe axis. Jeff was pointing out that ours is mounted with only point constraint and so the arm is free to rotate about an axis that goes through that point. This allows the camber and toe to be fully constrained by the rear rods. So as the suspension compresses the arm actually rotates about the camber and toe axis as well as articulating around the front pivot. 

I'll try and to see if I can figure out how to get a video to upload.

Whether the front pivot is inboard or outboard determines which point that rotation axis has to go through and certainly impacts the final suspension progressions that can be practically acheived with the packaging constraints under a 510.  

 

 

 

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volkswagner,

 

If you copy the entire URL at the top of your browser window and past it in the text field it imbeds here on Ratsun it embeds just fine. Not sure why the youtube share link doesn't work though.

 

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The "Z" link design using the outer mount is more of what I had pictured in my head. Maybe just move the outer mount inboard to gain clearance?

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volkswagner,

 

If you copy the entire URL at the top of your browser window and past it in the text field it imbeds here on Ratsun it embeds just fine. Not sure why the youtube share link doesn't work though.

 

Thanks, this is what I needed to see.

 

Looking forward to seeing it in metal. Keep up the awesome work!

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volkswagner,

 

If you copy the entire URL at the top of your browser window and past it in the text field it imbeds here on Ratsun it embeds just fine. Not sure why the youtube share link doesn't work though.

 

Well that's just too easy!

 

 

The "Z" link design using the outer mount is more of what I had pictured in my head. Maybe just move the outer mount inboard to gain clearance?

We're working towards a bolt in solution. If cutting/welding were required it would all be coming out and dual a-arm going in.

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Well that's just too easy!

 

 

We're working towards a bolt in solution. If cutting/welding were required it would all be coming out and dual a-arm going in.

That makes sense. How wide of a tire does the Z link accommodate? I think anything wider than 225 you would have to modify the fender well anyway.

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