AKG Spherical Control Arm Mounts

[modifiede30]

Anyone willing to share a pic of their installed AKG spherical control arm bushings/mounts that would show how much of the control arm shaft is within the bearing race? Mine seems to go to thru the race but stops just at the other side, leaving probably an inch of exposed on the control arm - if I reverse the mount, it won't fit, so i am confident its installed correctly, but it seems a bit sketchy to only grab the tip of the CA shaft. See below pic.

PXL_20201013_223842257.jpg

[bluptgm3]

So, if you swap L<>R they do not fit properly?


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[modifiede30]

No, if flipped it won't fit at all - the subframe or CA are too close to install one of the 2 joints. I'm not totally concerned running it as is - the CA slides all the way into the bearing race but only extends to the other end of the bearing - it doesn't stick out, but it is flush with the opposite side. You can see it has about an inch of room to slide in further, but can't because of the subframe attachment point. The distance between the subframe joint and CA are fixed, so no adjustment on the bushing is sufficient to allow them to both fit properly. If I flip it, you can see here how the CA is then too long to fit into the bushing.

PXL_20201013_223908490.jpg

[jimmypet]

Those AKG bearings are basically a copy of the 1st Generation Gruppe A front suspension part.
I have a set of those that came with my Gruppe A car and I could have sworn that the bearing slid all the way on the LCA up to the end of the machined portion of the control arm.

I think its worth calling AKG. Just catching the tip like that doesnt seem like it would be right.

[modifiede30]

Those AKG bearings are basically a copy of the 1st Generation Gruppe A front suspension part.
I have a set of those that came with my Gruppe A car and I could have sworn that the bearing slid all the way on the LCA up to the end of the machined portion of the control arm.

I think its worth calling AKG. Just catching the tip like that doesnt seem like it would be right.

I'm in touch with them - they didn't comment on the pic I sent as being a problem, and one of their images seemed to show a similar fit although it was much harder to see based on the angle of the pic. As mentioned, it does go thru to the other side of the bearing, but it doesn't stick out, just sits flush with the bearing race. Theoretically it should be okay but I'd hate to have something give out on a high speed sweeper - losing a control arm wouldn't be pretty.

[modifiede30]

Just heard back from them after a 2nd contact and their tech dept. said its normal to fit as pictured. Seems a little odd to me but I'm assuming if these were a major problem, it would have been posted about on any number of forums or the FB scene. I'll put the finishing touches on the install and hopefully get some testing around town to see if there's any problem. Just need to install the engine first.

[jimmypet]

If it were me and the mfg says thats the normal install orientation I think it would put it to bed for me.
The BMW track community is small, AKG who have always seemed to me to be a super reputable vendor have little to gain by shining you on and saying "sure its fine".
Maybe by not having the shoulder of the LCA butted against the spherical takes away any possibility of thrust loads on that spherical which is not how the bearing is made to be loaded?

I'll see if I can find any pics of the actual 1st gen BMW Motorsport part to compare, now just out of my own curiosity.
I played around with that stuff when I got the car but its been ages since I touched any of it, its all in spares tubs in the basement.
The car has the 2nd gen tubular front suspension on it.

[modifiede30]

I'm good with the last confirmation - seemed to be coming from the right place at AKG so I'll run them as is. I suspect it'll be fine.

[aeronaut]

If nothing else is wrong with the car (and I have no reason to believe there is), that's very unlike AKG. Just from these photo's, I'd buy elsewhere. SLR makes a competing product, and JUST from the pictures (hard to confirm) looks like it's not offset as much and would mount further up the end?

That said, I kinda prefer poly in this case.
I've always wondered about spherical in this application. I've experienced quite a bit of variance in LCA end diameter over just 3 sets of LCAs. (For what it's worth, VAC agrees and offers poly LCAB's with 2 sizes of inner-diameter). So in my mind, not every LCA would fit properly (OD mismatch of ID) into a metal spherical.

Am I missing something?

[modifiede30]

If nothing else is wrong with the car (and I have no reason to believe there is), that's very unlike AKG. Just from these photo's, I'd buy elsewhere. SLR makes a competing product, and JUST from the pictures (hard to confirm) looks like it's not offset as much and would mount further up the end?

That said, I kinda prefer poly in this case.
I've always wondered about spherical in this application. I've experienced quite a bit of variance in LCA end diameter over just 3 sets of LCAs. (For what it's worth, VAC agrees and offers poly LCAB's with 2 sizes of inner-diameter). So in my mind, not every LCA would fit properly (OD mismatch of ID) into a metal spherical.

Am I missing something?

These actually fit the spherical very tight - had to polish off some paint and grime to get them to fit into the bearing race, but not so tight I had to use a press. I have no issue with the fit of the bearing onto the arm pivot point. It sits fully in the race, but just doesn't come thru the other end, so it gave me pause. I actually spoke with a separate vendor, and they indicated their solid mounts fit in a similar way, so I'm less concerned about this now. I'll check with SLR as well. The mounting position seems correct given how much adjustment the spherical has to pivot out - when its in its fully retracted position, its pushing the CA forward so maximized caster. I've yet to do any type of adjustment to the suspension/alignment, so its current position should change once its tuned correctly.

Update - hadn't seen the SLR site or products, so bought a set for comparison. If they fit the same, I'll likely return them, but if they are a better fit, I'll sell the AKG. Will post pics of the comparison once they arrive.

[aeronaut]

Excellent !

[olemiss540]

I have the SLR pieces and the end of the control arm BARELY pokes out the other side with 1" or so of the end exposed. I am fairly confident you have yours installed correctly and that the SLR piece will have the same result. Just climbed under my car to verify.

[modifiede30]

I have the SLR pieces and the end of the control arm BARELY pokes out the other side with 1" or so of the end exposed. I am fairly confident you have yours installed correctly and that the SLR piece will have the same result. Just climbed under my car to verify.

Thanks - I'll see what happens. What you're describing sounds a little better than mine.

[modifiede30]

Installed one of the SLR tonight after a long delay in shipping, and they're definitely holding onto more of the control arm than the AKG versions. I am not as thrilled about the lack of material around the bolts on the SLR versions though. I guess its one or the other - might be selling either AKG or SLR versions soon if anyone is interested.

[bluptgm3]

Installed one of the SLR tonight after a long delay in shipping, and they're definitely holding onto more of the control arm than the AKG versions.

Got photos to show comparison?


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[jakermac]

I am not as thrilled about the lack of material around the bolts on the SLR versions though.

Sean does his homework. I don't think you have anything to worry about. He does FEA on all his parts.

[modifiede30]

Got photos to show comparison?


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I'll get some today/tonight.

[modifiede30]

Got photos to show comparison?


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Here are the 2 images for comparison. The AKG never excited the back side, SLR come all the way out.
PXL_20201114_231626416.jpg
PXL_20201114_231513822.jpg

[aeronaut]

Thanks for the pics.

[jonb94118]

Have used these for years. Good design that uses a sleeve over the end of the control arm that rides in the bearing. Seems more stout in my opinion compared to a rod end in single shear.
https://groundcontrolstore.com/produ...ol-arm-bushing

[modifiede30]

Have used these for years. Good design that uses a sleeve over the end of the control arm that rides in the bearing. Seems more stout in my opinion compared to a rod end in single shear.
https://groundcontrolstore.com/produ...ol-arm-bushing

I was somewhat curious to see how the adjustability of these might help with track setup - so went with the spherical.

[olemiss540]

Have used these for years. Good design that uses a sleeve over the end of the control arm that rides in the bearing. Seems more stout in my opinion compared to a rod end in single shear.
https://groundcontrolstore.com/produ...ol-arm-bushing

I have nightmares from the installation and removal of these things. Maybe I am a hack shadetree but HOLY CRAP if it didnt take the most brutal mechanical measures to get them on/off of vehicles.

[modifiede30]

I was certainly pleased with how easily the spherical bearings were installed. They need a little muscle and twisting them back/forth to get on, but easily installed to the point they can go on/off in about 5 minutes / side.

[aeronaut]

I have nightmares from the installation and removal of these things. Maybe I am a hack shadetree but HOLY CRAP if it didnt take the most brutal mechanical measures to get them on/off of vehicles.

I find it interesting that VAC sells hard poly FCABs in two inner diameters. They say because of wide tolerances on the OE LCA castings.

[ScotcH]

I find it interesting that VAC sells hard poly FCABs in two inner diameters. They say because of wide tolerances on the OE LCA castings.

Yup. Obvioulsy with the OE rubber bushings, it's a non-issue ... a bit of lube, and it's good to do. It's just as bad for the e46 aluminum arms ... I had to file mine down several times. The proper solution would be to put these on a lathe and make it a perfect known diameter, but that's just silly

FYI, We've used the treehouse (and now BimmerWorld trackCab) delrin LCABs and housings without any issues in the past. no adjustability on those.