Track only Alignment specs...

[tsk94]

Originally Posted by Bartledoo

I can definitely confirm several of the rear arms are spherically mounted. Just not sure which aren't as I haven't removed those yet at any point. The rear main control arm is spherically mounted to the wheel carrier. Ask me how I know! Okay I'll tell you. I accidentally rotated it and got it jammed into the control arm and got extremely pissed at the extra trouble I caused haha.

Perhaps I'm misunderstanding what you mean by 'spherically mounted'?

A spherical mount is a solid bushing. So even the main lower control arm is NOT spherically mounted as it goes into a non-solid bushing where it is connected to the spindle and the subframe. The same applies for the 3 rear control arms and the trailing arm. The bushings in the control arms are not all solid - spherical/ball-joints are solidly mounted. That's why there are upgrades from SPL and GC for rear arm replacements that are actual spherical ends. The same can be said for the bushings that the main control arm and trailing arm mount to in the subframe and spindle. Those can be replaced with true solid bushings - in the same way the solid subframe bushings are commonly replaced.

[Bartledoo]

Originally Posted by tsk94

Perhaps I'm misunderstanding what you mean by 'spherically mounted'?

A spherical mount is a solid bushing. So even the main lower control arm is NOT spherically mounted as it goes into a non-solid bushing where it is connected to the spindle and the subframe. The same applies for the 3 rear control arms and the trailing arm. The bushings in the control arms are not all solid - spherical/ball-joints are solidly mounted. That's why there are upgrades from SPL and GC for rear arm replacements that are actual spherical ends. The same can be said for the bushings that the main control arm and trailing arm mount to in the subframe and spindle. Those can be replaced with true solid bushings - in the same way the solid subframe bushings are commonly replaced.

It looks like all of the rear arms aside from the trailing arm are spherically mounted to the spindle. If you check the parts diagrams they will be referred to as ball joints.

It looks like all of the mounting to the subframe is via rubber bushings, but I'm not sure about the toe arm in that regard, since it has a ball joint on at least one side and photos show both sides looking identical so it may have ball joints on both sides.

http://bmwfans.info/parts-catalog/E9...el_suspension/

The subframe diagram can be found there too.

[tsk94]

Originally Posted by Bartledoo

It looks like all of the rear arms aside from the trailing arm are spherically mounted to the spindle. If you check the parts diagrams they will be referred to as ball joints.

It looks like all of the mounting to the subframe is via rubber bushings, but I'm not sure about the toe arm in that regard, since it has a ball joint on at least one side and photos show both sides looking identical so it may have ball joints on both sides.

http://bmwfans.info/parts-catalog/E9...el_suspension/

The subframe diagram can be found there too.

That's correct, most of the arms have one end spherical and the other as a rubber bushing - I believe one of them is spherical both ends. Not sure on the main control arm though, I was pretty sure at least one end was a rubber bushing.

Regardless of the specifics, it's still an upgrade to go with the rear set of SPL or GC rear arms. More adjustability and full spherical mounts. The M3 GT4 replaced bushings in the rear arms and trailing arms but retained the stock arms. However I believe at the time this was mandated by rules - the bushings could be replaced but not the arms. Having one end a ball-joint is better then nothing, but a rubber bushing on the other end will result in flex/distortion under load.

[Bartledoo]

Originally Posted by tsk94

That's correct, most of the arms have one end spherical and the other as a rubber bushing - I believe one of them is spherical both ends. Not sure on the main control arm though, I was pretty sure at least one end was a rubber bushing.

Regardless of the specifics, it's still an upgrade to go with the rear set of SPL or GC rear arms. More adjustability and full spherical mounts. The M3 GT4 replaced bushings in the rear arms and trailing arms but retained the stock arms. However I believe at the time this was mandated by rules - the bushings could be replaced but not the arms. Having one end a ball-joint is better then nothing, but a rubber bushing on the other end will result in flex/distortion under load.

Yea no doubt the upgraded arms are an upgrade.

[//steve\\]

Originally Posted by Bartledoo

I can definitely confirm several of the rear arms are spherically mounted. Just not sure which aren't as I haven't removed those yet at any point. The rear main control arm is spherically mounted to the wheel carrier. Ask me how I know! Okay I'll tell you. I accidentally rotated it and got it jammed into the control arm and got extremely pissed at the extra trouble I caused haha.

The rear upper arms are a combination. Rubber on one end and spherical on the other. I believe the rubber is on the knuckle end of things. The big lower arm I believe is rubber on both ends and trailing arm is the same.

[nicksm3]

Originally Posted by LS3Series

I think that is a lot of rear toe isn't it? I don't know your exact tire size, but my 275/35/18 are .12 degree per side, .24 Total toe

Everything else looks awesome to me! -4.1 front camber

I am on Pirelli DH 305 square full racing slicks

[derbo]

Originally Posted by //steve\\

The rear upper arms are a combination. Rubber on one end and spherical on the other. I believe the rubber is on the knuckle end of things. The big lower arm I believe is rubber on both ends and trailing arm is the same.

Rubber bushings:

Camber arm (one with the spring) inboard end
Upper Arm outboard end
Guide rod outboard end
Trailing arm both ends

[911r]

Originally Posted by derbo

Rubber bushings:

Camber arm (one with the spring) inboard end
Upper Arm outboard end
Guide rod outboard end
Trailing arm both ends

So ...

-SPL rear toe links,
-SPL rear upper arm links,
-Bimmerworld camber arm bushings,
-Bimmerworld rear trailing arm bushings,
-solid rear subframe bushings & solid diff bushings

Would eliminate all rubber bushings in the rear end?

[Bartledoo]

Originally Posted by derbo

Rubber bushings:

Camber arm (one with the spring) inboard end
Upper Arm outboard end
Guide rod outboard end
Trailing arm both ends

Perfect, thanks! This helped me make sense of the diagrams without having to take a wheel off, since the diagrams don't make it too easy to tell which side is rubber bushing and which is spherical for the two shorter arms. So the toe arm is spherical on both ends.

Ballers on a budget have five bushings to replace then.

[VictorH]

My set up not as radical as what most of you are running but my tried and true set-up for me for track. Have monoballs up front, solid subframe bushings rear, Fall-lIne toe arms in rear, Fall-line solid camber shim kit, rest of suspension is stock (except for shocks/struts).

Front Camber -3.5 degrees
Rear Camber -2.25 degrees

Front toe 1/16" total toe, OUT
Rear toe 1/16" total toe, IN

Toe is old school with toe plates, but car tracks straight and I have everything marked so I can switch from street to track settings. This is my street car too, but I wouldn't run this set up long-term for street use with above alignment settings.