Rear vented discs

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Rear vented discs

Postby slidewaysbmw » Wed Feb 12, 2014 8:29 pm

Anybody know of a rear vented disc mod for a e30 .
I'm running 15" compomotive wheels and original four stud hubs..
For the mot I need to keep the hand brake shoes inside the discs so probably looking at a rear disc from another bmw.
I think I heard of a 328 rear disc and caliper conversation with the discs re drilled to four stud and a spacer to make up the difference between the e30 hub diameter and the e36 disc hole.anybody no of this mod or have other ideas .thanks
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Re: Rear vented discs

Postby rally_rich » Thu Feb 13, 2014 9:41 pm

I am quite interested in this post as well as it is equally applicable to the rear brakes on compacts. Is there an easy swap?

I havent got to the 'brakes' part of my build so I havent looked into it too much yet. I will probably go with standard solid read discs to begin with and see how they go. What are peoples thoughts on these so far? Do they need to be upgraded? I did compare the rear vented discs off the E36 328 estate I dismantled. From what I could see they could be swapped over if you swapped the wheel bearing and hub as well. The outer diameter of the hub (inner wheel bearing race diameter) is different. The compact brake discs/hubs are quite deep (piccy below) so I think they have a slightly larger bearing due to the moment on the hub.


The E36 estate was about ~35mm shallower. So I would lose track width with this modification and I am trying to go wider anyway. I don't really want to down size the bearing as I am increasing the loading as well. I have spoken to someone who has a euro compact widetracked with a spacer like me and he was wider and has had no bearing problems after plenty of rallying.

I think a back up plan if there is no straightforward swap could be to machine the original brake disks to take the disc section off so you could bolt a vented rotor to it like in the piccy below. That way you keep the hand brake mechanism. The modified disc/bell is never going to wear if your using a hydraulic hand brake so its a one off fix. The wilwood disc rotors and not too badly priced. It's an option I think.

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Re: Rear vented discs

Postby Kevin » Wed Jul 16, 2014 9:13 am


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