Eccentric bushings for IRS camber - anyone interested?

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maurice
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Eccentric bushings for IRS camber - anyone interested?

Post by maurice » Fri May 25, 2018 9:48 am

Hey guys, I'm in the process of building my Subaru powered mid engine bug and I ran into a problem. My camber was around 3 degrees, and I still hadn't lowered it completely. Instead of rewelding my trailing arm pivots, I had my neighbor make me some delrin eccentric bushings, and it brought my camber back to around 1 degree.

I know I'm not the only one struggling with this problem. So would anyone be interested in me making a batch of these? It requires some time on a lathe and a mill, so they aren't going to be as cheap as a normal set, but likely easier than flipping and welding trailing arms. Also good for off road. I'll likely make these out of polyurethane instead of the super stuff delrin pictured.

The photos don't show the tapered washer on the other side. I didn't do an accurate measurement of before and after camber, but I can make these in any angle, though I may stick with the 2 or so degrees I got out of this one.
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Right wheel has the bushing, left wheel doesn't
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H2OSB
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by H2OSB » Fri May 25, 2018 10:19 am

How much $$ are you thinking you'll ask for a set?

H2OSB

maurice
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by maurice » Fri May 25, 2018 10:28 am

Not sure, we'd have to see how much materials and our jig setup run. Hoping around $70-80, But could less. Hard to say exactly since these first two took awhile to make. Trying to see how much interest there would be.

H2OSB
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by H2OSB » Fri May 25, 2018 5:15 pm

Got'cha. Well i think I'd be interested if you're able to get them down to around $50

H2OSB

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ChadH
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by ChadH » Sat May 26, 2018 12:46 pm

Interested..not sure yet where my camber will be untill I get suspension installed my build though. How much range of camber do you think those provide?

maurice
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by maurice » Sat May 26, 2018 1:32 pm

I got roughly a couple degrees out of it. I could probably make more with even more taper, and whoever installs it can index/turn them so they provide less.

H2osb: I'll let you know what they run, someone pointed out that polyurathane might stink milling, so we may stick with delrin (more expensive than poly).

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Piledriver
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by Piledriver » Fri Aug 03, 2018 9:09 pm

There are a herd of polyamides that machine well and would work great, some like some nylons are also decent bearings and available impregnated with moly and/or graphite and not even terribly expensive.

Someone made eccentric bolts at one point...
There was another solution that made the whole mount movable posted, I strongly considered it.

I personally was able to get to ~.5 degree using the standard adjustment, but something more elegant like a vernier adjustment rather than the usual "crank on it and check the result" would be nice.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

maurice
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Re: Eccentric bushings for IRS camber - anyone interested?

Post by maurice » Fri Aug 03, 2018 10:53 pm

I emailed the guy who did bolts, he doesn't do them anymore. The camber bushings were not a bad idea, but you're right, moving the whole bracket up is the correct way to do it.

We ended up lowering the bug ALL the way down to help with the cv joint angle on the mid engine setup. My neighbor and I are making two brackets on the torsion tube and connecting the trailing arm with heim joints. One bracket will be slotted for camber adjustability.

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