Midwest front anti sway bar

[rx1900]

Are your reproductions available?

Yes, they are !!! Pics of them - loose and installed - can be seen is this thread: Scroll to the bottom of my post

Fiat X1/9 suspension re-fresh kits

Update April 23/22.....available again here: https://xwebforums.com/forum/index.php?threads/fiat-x1-9-and-lancia-scorpion-suspension-re-fresh-kits-available-again.42286/ Hi Folks. Well I am proud to present my latest project. This time it is complete suspension re-fresh kits. Typically one...

xwebforums.com

I have plenty of just the grommets in stock. Although I dont think I ever posted a separate listing for them. I will try to do that. Meanwhile...just PM me if you want some.....

and come on BobKat......you're from Alberta...surely you know the song I referred to.........

 

[Dr.Jeff]

Do you have a one piece set that you can take measurements of? could look at trying both one and two piece. Two piece in a HDPE would be a really good permanent fix. but TPU in a one piece would be a close second.

I have one used one that's in decent shape. Should be good enough to get the needed measurements from. Please remind me to do that, I'm sitting in a office with my mom waiting for a appointment right now and I'll forget.

With your ability to make 3D parts in multiple densities and structures, you could design a one piece item with a softer lip on one end to allow easier installation. Then make the middle shank section harder for greater durability.

Also notice how one of the stock rubber bushings wears and deforms much more than the other one. Maybe make two different densities for the replacements to compensate for the unequal load. Same for the little isolator, make one end stronger....it also wears unevenly.

 

[Dr.Jeff]

It is not like a beam axle. It still allows the wheels to move independently. Any sway bar limits the independent movement somewhat. With the sway bar mounted to the radius arms the actual mounts have to flex to allow movement as they are rotating on a different radius. Unusual setup but could be effective. It would take a thicker bar than a typical sway bar to compensate for the flex in this setup.

Agreed. That's what I was trying to describe in a earlier post regarding the rear bars on many American vehicles.

I'd completely forgotten about those earlier posts (page 1) and the related pics, as referenced by @Robo1098 . I did not intend to imply the X was like a solid beam rear suspension, just using that pic to make a point about the MWB mounting arrangement.

Post #9 from Kmead shows a modification to the MWB mounting arrangement that Mark P did ages ago. It moves the forward mounts from the radius rods to the chassis. I agree something along those lines would seem to be a better approach.

 

[Robo1098]

Agreed. That's what I was trying to describe in a earlier post regarding the rear bars on many American vehicles.

I'd completely forgotten about those earlier posts (page 1) and the related pics, as referenced by @Robo1098 . I did not intend to imply the X was like a solid beam rear suspension, just using that pic to make a point about the MWB mounting arrangement.

Post #9 from Kmead shows a modification to the MWB mounting arrangement that Mark P did ages ago. It moves the forward mounts from the radius rods to the chassis. I agree something along those lines would seem to be a better approach.

I didn't think you were implying that an X was like a solid beam. Any sway bar is going to limit an independent suspension to act independently. LOL. It does make it act more like a solid beam though.

 

[Bobkat]

I honestly can't remember if I put those yellow bushings in the rear of the car or not when I did the rear sway bar. But another can of worms possibly. Any have info on the yellow and effects on the rear suspension. Getting old sucks can't even remember doing it or how it was done if I did.

 

[Dr.Jeff]

I honestly can't remember if I put those yellow bushings in the rear of the car or not when I did the rear sway bar. But another can of worms possibly. Any have info on the yellow and effects on the rear suspension. Getting old sucks can't even remember doing it or how it was done if I did.

If you are referring to the yellow VAS urethane bushings for the rear suspension A-arms, there has been some discussion on it. However the focus was more on using urethane bushings for that specific location, and not really about the VAS ones in particular. The point that was made is the two pivots (on each arm) are on different axis to one another. Therefore as the arm articulates the pivots are actually fighting each other, which puts strain on them. The argument was that using any bushings that are firmer than the original rubber transfers that added stress to the mounting brackets (on the chassis) for those bushings. As a result others have experienced cracks in the chassis and mounts.

I'm not a suspension design engineer so I don't know if there was a specific reason for Fiat making the pivots on different axis like that. But it does cause considerable resistance to rear A-arm movement and places additional load on the surrounding components....even with the stock bushings. So I can see how using firmer bushings might(?) cause problems. When X1/9 racers build tubular A-arms with heim joints for the pivots, that off-axis issue goes away. The heim's monoball compensated for it as the arm moves. And the result is a much easier and smoother articulation. In the end I decided to stick with original style rubber bushings on my latest restoration....despite not liking rubber bushings at all.

I bet my memory has become worse than yours. I'd forgotten about a earlier post I made in this thread, until Robo1098 reminded me of it.

 

[Dr.Jeff]

@Bobkat, last night I had an idea for the front radius rod bushings and isolator inserts. Since you can make new bushings (donuts) to your own design (3D printing), how about creating a set that incorporates both components (the bushings and the isolators) together. One bush (donut) will have a cylindrical extension projecting from it (to act as the isolator), and the matching other bush will have a recess for that projection to fit into. So when the two donuts are assembled on either side of the mounting bracket, the extension cylinder goes through the hole in the mount, and into the other donut. Hope that makes sense, if not I can try to illustrate it.

 

[Bobkat]

If you are referring to the yellow VAS urethane bushings for the rear suspension A-arms, there has been some discussion on it. However the focus was more on using urethane bushings for that specific location, and not really about the VAS ones in particular. The point that was made is the two pivots (on each arm) are on different axis to one another. Therefore as the arm articulates the pivots are actually fighting each other, which puts strain on them. The argument was that using any bushings that are firmer than the original rubber transfers that added stress to the mounting brackets (on the chassis) for those bushings. As a result others have experienced cracks in the chassis and mounts.

I'm not a suspension design engineer so I don't know if there was a specific reason for Fiat making the pivots on different axis like that. But it does cause considerable resistance to rear A-arm movement and places additional load on the surrounding components....even with the stock bushings. So I can see how using firmer bushings might(?) cause problems. When X1/9 racers build tubular A-arms with heim joints for the pivots, that off-axis issue goes away. The heim's monoball compensated for it as the arm moves. And the result is a much easier and smoother articulation. In the end I decided to stick with original style rubber bushings on my latest restoration....despite not liking rubber bushings at all.

I bet my memory has become worse than yours. I'd forgotten about a earlier post I made in this thread, until Robo1098 reminded me of it.

I did install them. I had a look today on the hoist. I refreshed my memory about how I modified the sway bar mounts also. the yellow bushings do not look worn or stressed in this location. Like you said maybe the softer is better for the off axis locations? I will have to get a softer TPU to try a bit of and upgrade in this location but I am happy to say the yellows look brand new so no big rush here. This off axis rear control arms are common on new Audi's. not sure the reasoning but they are free moving in the centre but stiffen up as you push up or down so maybe that is the reason.

 

[Bobkat]

@Bobkat, last night I had an idea for the front radius rod bushings and isolator inserts. Since you can make new bushings (donuts) to your own design (3D printing), how about creating a set that incorporates both components (the bushings and the isolators) together. One bush (donut) will have a cylindrical extension projecting from it (to act as the isolator), and the matching other bush will have a recess for that projection to fit into. So when the two donuts are assembled on either side of the mounting bracket, the extension cylinder goes through the hole in the mount, and into the other donut. Hope that makes sense, if not I can try to illustrate it.

I understand what you are saying. Maybe adding them to both sides kind of like the sway bar link bushings. That way they would share the centering. Kind of like the two piece snap together. It this area that two filament printers would shine. You could print the donut out of a softer material and blend the isolators to a stiffer material all in one piece. It seems so simple there must be a reason there are three pieces?

 

[Dr.Jeff]

I understand what you are saying. Maybe adding them to both sides kind of like the sway bar link bushings. That way they would share the centering. Kind of like the two piece snap together. It this area that two filament printers would shine. You could print the donut out of a softer material and blend the isolators to a stiffer material all in one piece. It seems so simple there must be a reason there are three pieces?

Exactly. Use two types of material to allow "give" in the donut portion, and strength/durability in the isolator portion. The only reason I suggested extending the center "cylinder/sleeve" (isolator portion) through into the other donut is to avoid a seam in the middle - where the greatest stress and wear would exist. The pivot mount is not really thick so the rod pivots on a small footprint. That focuses the load to that point. And that's where the isolator is likely to fail first. I'm not sure exactly how much difference it would make to avoid a seam there, but it seems to me that would help.

I'm sure the reason there are three pieces in the original design is either due the isolator being a after thought, or a cost savings decision. I suppose a third reason might be the engineers did not think of a two piece arrangement at the time.

 

[Dr.Jeff]

@Bobkat, I sent you some information on the isolator dimensions. Check your "inbox".

 

[Bobkat]

So shake down test and other than a slight off center of the steering wheel car feels really solid , planted and quiet in the suspension. No clunking over bumps which I suspect was solved by the new sway bar bushings and bigger hardware on the sway bar end links . Did reveal a wheel balance issue between 140 and 150 but gone by 160kph. But now feel confident that I can dial in some other modifications and will be able to align it myself.