[RyanDavies]

So, the custom offset lower bushings are done in prototype form.





These replace the lower front control arm bushing, and are legal to use in STX. They should allow for .5-.6 more degrees of camber than the stock lower control arms.

Obviously, they'll also fit E90/E92 Non-M cars as well. If anyone is interested, I can have another couple sets made up. I know that two sets are spoken for in addition to my one, and would probably not be a big deal to add any others. Because everything is custom made and machined, (including the metal sleeve), they'd go for around $150 / set (both sides). You've probably got a month or two to speak up on them, so do so . No money will be made on them, just trying to help folks out where there is not a reasonable alternative.

The SuperPro bushings that do something similar are very failure prone, as in my video here:

[boro92]

The problem with bushings in this location is that the pivot point of the arm isn't just on a single axis. As a result, any poly bushing gets killed, and if this is Delrin (looks like it), it will suffer the same fate. FWIW. I LOVE THIS. But it needs to be spherical.
The OE inner "bushing" is actually is ball joint for this reason. At least, on my xdrive this is the case.

[RyanDavies]

Originally Posted by boro92

The problem with bushings in this location is that the pivot point of the arm isn't just on a single axis. As a result, any poly bushing gets killed, and if this is Delrin (looks like it), it will suffer the same fate. FWIW. I LOVE THIS. But it needs to be spherical.
The OE inner "bushing" is actually is ball joint for this reason. At least, on my xdrive this is the case.

It isn't a real ball joint, but a rubber bushing that allows multi-axis on the other cars, from what I have seen.

For class rules, a spherical is disallowed. You can't run any additional metal content in the bushing than exists from the factory. (The metal sheath around the rubber bushing from the factory at least gives some wiggle room with total metal content).

In practice, the y-axis deflection is not very large, and when replaced with delrin / poly, the force will go to the ball joint. Poly bushings are popular there (I dislike them in general in comparison to delrin), and seem to have reasonable longevity (I know enough racers who have used a non-offset, OTS delrin or poly bushing for multiple seasons without introducing play).

For *most* people, the answer is probably still to go with the M3 arms. They won't get QUITE as much camber (I lost a couple tenths of a degree switching from the SuperPro to the M3 arms I used for testing, and these bushings are slightly more offset than the "most" offset you could make the SuperPro). Swapping in the M3 arms takes ten minutes for both sides, and is an OTS part, the TRW version of which is available for $70 or so a piece.

In short, I think this is about as good as I'd be able to reasonably do with the rules as they exist now. I don't love it, but them's the breaks.

[boro92]

Interesting!
Good to know that this will work and that the lack of deflection in this area will not pose to be a big problem. I would be interested in this for an Xdrive car, as the m3 arms won't work for the car. I have gone to spherical tension rod bushings, but the LCA still runs the stock setup. Any additional camber I can get is a bonus. I'm maxed out at -2.7 at my current height at the moment.

[RyanDavies]

FE1RX has done a lot of suspension analysis on deflection / construction of a lot of the bushings on the car as well. I've yet to find anything I substantially disagree with him about (although my empirical testing of spring rate choices has yielded vastly different result).

I'm unsure if they will work with an x-drive arm. If you're seriously interested in a set, let me know. I'm not profiting off these at all (nor is the person manufacturing these), they're just a small enough run they are hard to do for less than this.

[AtlasM]

The control arms for xdrive are totally different, it would have to be a different bushing design.

Rwd:



xdrive:

[boro92]

Originally Posted by RyanDavies

FE1RX has done a lot of suspension analysis on deflection / construction of a lot of the bushings on the car as well. I've yet to find anything I substantially disagree with him about (although my empirical testing of spring rate choices has yielded vastly different result).

I'm unsure if they will work with an x-drive arm. If you're seriously interested in a set, let me know. I'm not profiting off these at all (nor is the person manufacturing these), they're just a small enough run they are hard to do for less than this.

Hi Ryan,

I am seriously interested in a pair for xdrive, and can provide deposit should you prefer to have one. This front end needs all the help it can get, and with no aftermarket support, I am more than happy to buy a delrin solution from you.

[boro92]

Originally Posted by AtlasM

The control arms for xdrive are totally different, it would have to be a different bushing design.

Rwd:



xdrive:

And this is why I say it's a ball joint at least on the xdrive.
That pic still looks like a ball joint to me If that is the case, then I'd need to assess whether delrin will work in this area given the non-radial loads it may be seeing. That said, an offset joint in this location to help with camber would be great - provided that there's sufficient room for any real eccentric bushing to live there.

[RyanDavies]

It is a ball joint there. You wouldn't happen to have (or easy access to) an extra arm, would you? The easiest answer to see if the bushing would work would be to take some measurements. Either one of us could do that (if you have a digital caliper). I'll do some work tonight and find some pictures / parts diagrams to look at the arm.

EDIT: Okay, doing some research, it looks like the SuperPro bushing is an interchange part between X-Drive and not X-Drive. My bushing's exterior dimensions are identical to that, so it should work just fine.

https://www.ecstuning.com/BMW-E90-33...ngs/ES3045710/

Also, I have some brand new adjustable caster bushings (can reduce caster / add static camber or vice versa) I'd sell you really damned cheap if you want something else.

https://www.ecstuning.com/b-superpro...pf394095k~spr/

[feuer]

Originally Posted by boro92

And this is why I say it's a ball joint at least on the xdrive.
That pic still looks like a ball joint to me If that is the case, then I'd need to assess whether delrin will work in this area given the non-radial loads it may be seeing. That said, an offset joint in this location to help with camber would be great - provided that there's sufficient room for any real eccentric bushing to live there.

Yes, XI and M are ball joint and none M is a just a regular bushing. Also, as you said offset joint will allow camber changes.

[RyanDavies]

Originally Posted by feuer

Yes, XI and M are ball joint and none M is a just a regular bushing. Also, as you said offset joint will allow camber changes.

So we're clear here, this is a shrink-fit bushing that will not allow camber *adjustments* there, but you can increase/decrease camber based on how you press the bushing into the arm. The recommended use case, of course, is to increase camber.

[feuer]

Originally Posted by RyanDavies

So we're clear here, this is a shrink-fit bushing that will not allow camber *adjustments* there, but you can increase/decrease camber based on how you press the bushing into the arm. The recommended use case, of course, is to increase camber.

Correct. Few aftermarket companies offer adjustments is similar execution. Other car makers too. MBenz uses eccentric bolts to offer the same.

[John v]

Hey. So I'm the maker of these bushings. The pictures Ryan posted are of the prototype units. I want him to try these out and tell me about any installation or other issues before I make more of them, but once he's happy that they work as expected I'm happy to make more sets.

[John v]

Looks like Davies has moved on from his 128 autocross car since he bought a plastic fantastic.

Anyone else interested in being the test car for a pair of these bushings?

[Blown95ImpalaSS]

hi john, I was going to order and install poly front control arm bushings and stumbled upon this thread. happy to be your tester but I have a 135 which shares the same control arm with e90/e92.

if this is OK feel free to shoot me a PM with your info and we can discuss

[ornicar]

Hi,

i have a question please, maybe someone know the answer and can help.

Is it possible to fit the Xi ball joint in place of the none M bushing?

For information, I don't want to fit the M3 LCA because i have enough camber for my needs (-0,5º thanks to M2 Knuckle), & i don't want bump-steer issues.
but i would really like to have the advantages of the ball joint in the standard arm.

thanks!

Edit : another option is the turner monoball upgrade :



https://www.turnermotorsport.com/p-4...oball-upgrade/



have any of you tried this kit?