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Discussion Starter #1
I have been looking for some past articles on the development of the Borden kit to put spherical bearings into the IRS rear knuckle. I thought I had a bookmark to them but can't find it now, neither can Google.

The article may have been on the SuperCoupe forum or on the old MN12 forum, which I think is now shut down

I've found the link to Whitby's who sells them but I am looking for some of the research and logic that went into them.

does anyone recall this and can you point me in the right direction

Thanks

Paul
 

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Wouldn't spherical bearings have much less strength, especially while hard cornering?

EDIT:The reason I say that is the balls only can be so big due to the axle going thru the middle, and our stock ones are tapered rollers almost 1/2" long.
 

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Discussion Starter #3
Confused

Grog6
The spherical bearings are used in place of the rubber/ureathane bushings on the knuckle. The idea is to limit deflection of the joint during cornering.

the units stand up well to road racing and 500HP drag racing

Still looking for the links to the original articles by David Borden

Paul
 

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The spherical bearings are used in place of the rubber/ureathane bushings on the knuckle. The idea is to limit deflection of the joint during cornering.

the units stand up well to road racing and 500HP drag racing
I understand. Removing the compliance of the rubber would tend to reduce wheel hop, and make the wheel track better.

Neat Idea!

Thanks, Paul. Hadn't heard of that mod for these cars.

I did see the delrin bushings the guy is making on SCCOA; this would be better, I think.
 

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Discussion Starter #5
Issues with Delrin

Grog6
The delrin bushings do work and are less expensive, however manufacturing tolerances as they are, some issues are created with pivot bolt alignment and axle movement.

If you bolt up just the upper, everything is great. When you add the two lower ones, things start to get into a bind. To make the delrin work, you need to loosen the bolts slightly which creates other issues.

The angular alignment feature of the spherical bearing compensates for the frame brackets not being welded exactly in line or the knuckle bores not parallel.

It appears the drawback to the spherical bearing, though, is the cost of use. The adapter kit is not cheap.

Paul
 

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Grog6
The delrin bushings do work and are less expensive, however manufacturing tolerances as they are, some issues are created with pivot bolt alignment and axle movement.

If you bolt up just the upper, everything is great. When you add the two lower ones, things start to get into a bind. To make the delrin work, you need to loosen the bolts slightly which creates other issues.

The angular alignment feature of the spherical bearing compensates for the frame brackets not being welded exactly in line or the knuckle bores not parallel.

It appears the drawback to the spherical bearing, though, is the cost of use. The adapter kit is not cheap.

Paul
I disagree with your opinion that tightening the bolts when using Delrin bushings creates bind. I'm the "guy" on SCCoA that makes Delrin Bushings for the Thunderbirds and Mark VIII's (LCA's and Knuckles), and have them installed in two of my own cars, and have installed them in others, all torqued to factory specs.

Have you actually tried it?

In reality, the frame brackets give and adjust to the LCA bushing bore centerline as they clamp on the 1 1/4" diameter hard-coated aluminum spacers when you tighten the bolts.

Good luck with your spherical bushing project.
 

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I'm guessing this is for a Cobra kit car using Thunderbird/couger/Mark VIII pieces for the IRS?

Just from the top of my head thinking of the mn12 setup, I don't see why the knuckle couldn't have all Delrin or any other type of regular bushings. It just goes up and down, the LCA mounts don't change angle at all since its solid.

But the LCA to sub frame mounts could use spherical bearings vs the regular rubber ones since aligning the rear toe creates bind with regular bushings with the front and rear bushings not lining up perfectly.

I'm just thinking of the mn12 setup though with the solid LCA, do you have separate bars going to each knuckle mount? If so then yea, I see what you mean about binding.
 

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But the LCA to sub frame mounts could use spherical bearings vs the regular rubber ones since aligning the rear toe creates bind with regular bushings with the front and rear bushings not lining up perfectly.
If you loosen the forward LCA bolts while adjusting the rears, this isn't a problem.
 

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I'm guessing this is for a Cobra kit car using Thunderbird/couger/Mark VIII pieces for the IRS?
I'd still want a Jag IRS for the brake relocation; that's the way my bud's kit car is built.

~30lbs a wheel on unsprung weight difference, IIRC.
 
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