e82 / 135i rear performance 2 piston caliper

[Frentz]

Hello to all,

in this post, the rear calipers from 135i performance that everyone says cannot be mounted immediately catch the eye ...
And then the question: is there any news about it? does anyone know things?

thanks

https://www.facebook.com/Skyermotorsport/photos/a.266341577254444/801663110388952/

 

[maupineda]

They wont fit as in “bolt on”.

You can though, change the trail arm to the non-M and they would now bolt right on with the Z4M rotor.

If you install all M bushings to the Non-M trail arm the you don’t loose anything. But that would be more involved than just put on Porsche Boxter S rear calipers.

 

[Jakg]

They wont fit as in “bolt on”.

You can though, change the trail arm to the non-M and they would now bolt right on with the Z4M rotor.

If you install all M bushings to the Non-M trail arm the you don’t loose anything. But that would be more involved than just put on Porsche Boxter S rear calipers.

Do you have any more information on this?
I didn't think you could fit the rear Z4M discs onto a "regular" Z4?

 

[maupineda]

Here are a few images

E86M Trailing Arm


E86 Non-M Trailing arm


^^ Notice how the ears for mounting the calliper have different lengths, the M´s are longer, thus placing the calliper outside the rotor area. The images below are of a US M3 (non-floating/drilled rotors). but the dimensions are the same (328x20)





If you have a Non-M, you can use an M rotor with the M e-brake assembly.

If you an M, you would need a Non-M trailing arm with the shorter ears, and would also need to transfer the ball joints to not downgrade these components (Non-M have bushings ILO ball joints)

 

[srhutch]

There must be other differences to the trailing arms. The axle is shorter on the ///M for a start. If the lugs were the only difference only one casting would be needed as could easily be machined.

 

[GuidoK]

There must be other differences to the trailing arms. The axle is shorter on the ///M for a start.

The axle is shorter probably because the diff is wider (188k vs 215).
But there are other major differences that makes me believe this mod is not possible.
The inner bearing diameter is different so a z4m output shaft won't physically fit. (collar nut is also bigger on the /m)
A very very long shot might be to try and fit the outer cv joint of the non m axle on the /m axle
Also a z4m rotor won't properly fit a rear non m arm because of the handbrake difference. Your car won't meet MOT if you dont adapt.
either by making custom brakeshoes (how I did it) or by reducing inner diameter of the rotorhat (have seen that too)
There is no bolt on solution I think. One way or the other bespoke parts have to be fabricated.

 

[maupineda]

There must be other differences to the trailing arms. The axle is shorter on the ///M for a start. If the lugs were the only difference only one casting would be needed as could easily be machined.

In my research on the E46 forums, the only documented difference I found with the trailing arm designs appeared to be the mounting points for the calliper carrier, and the fact that the ///M uses two ball joints, and the Non-M a ball joint and a rubber bushing. BMW seems to have decided to create two castings, so the M casting also gets the ///M logo. I was going to get a set of used trailing arms to compare with my ///M ones, but as you can infer at this point, fitting the rear 135i callipers was such a FAF that I stopped looking into that and went the Porsche route.

Can it be done? yes, but then you will have to mix and match components, at what point, getting a bracket to mount the rear Porsche calliper is the most sensible option.

 

[Frentz]

wouldn't a way be possible with the correct brake disc ?!
ie wider in diameter both outside and inside but with the handbrake part similar ?! (or even changing the handbrake as on the non-M)

 

[Frentz]

another solution if the trailing arm is from alluminum (as i think):

you can fill the holes of the ears and make them new in the correct position :wink:

 

[maupineda]

wouldn't a way be possible with the correct brake disc ?!
ie wider in diameter both outside and inside but with the handbrake part similar ?! (or even changing the handbrake as on the non-M)

Indeed, but that leads into a custom rear disc, the rear rotor of the ///M E90/2 would have the right diameter, but the hat height is very different, so you get into another issue. again, the solution is relatively easy, just use non ///M trailing arm, rebuild with new ball joints and move on, but unless you have a very cheap set of rear 135i callipers, the cost of it will be probably more than just getting Porsche callipers with the right adapter, which exists.

 

[maupineda]

another solution if the trailing arm is from alluminum (as i think):

you can fill the holes of the ears and make them new in the correct position :wink:

but is it worth it? I mean, if you do it for the fun of it, and the satisfaction of developing something unique, I am all for it, but I personally did not have the skills or access to someone who I knew could do the job properly.

 

[Frentz]

surely I wouldn't do the job but I would do it, in case I decide to proceed.
I really don't like the porsche calipers ... so anyway I would not like to mount them here.

https://www.youtube.com/results?search_query=aluminum+brazing

 

[maupineda]

surely I wouldn't do the job but I would do it, in case I decide to proceed.
I really don't like the porsche calipers ... so anyway I would not like to mount them here.

https://www.youtube.com/results?search_query=aluminum+brazing

the arms are not aluminum, they are cast iron.

 

[Frentz]

ah ok, thanks, but is not a problem at all

 

[Frentz]

I have found a solution:

rear rotor of 550i (345*24 mm) with two little mod. that's no perfect but is ok

thanks to Ludwig Reindl.

https://drive.google.com/file/d/14ouTTwol57om8qhr-LYfLSO5Cc7GLokg/view?usp=sharing