Alright gentleman, I need some help with the specifications of MINI brake calipers. I have a BMW E30 which I'm sure some of you are familiar with, and I've been doing research into upgrading its brakes inexpensively and retaining the 4-lug set-up rather than getting all the components to swap to 5-lug. The rear rotors between the two are very similar as shown here. MINI E30 Looks to me like you could use a MINI caliper on an E30 rotor for an upgrade as the MINI has larger brake pads about the same size as E36s. What I've managed to find about the calipers is that there are at least two different types of rears. There are pre 04/03 I believe is the month and year that I've read which by pictures I've seen seem to have the caliper guide pins very close to the housing of the caliper around the piston. Then, the later calipers move the guide pins much further outboard. I'm not sure if these are the only types of calipers or if there are many more. Anyway, I'm interested mainly in the specs of the earlier caliper as it seems very similar to the E30's. Here's the measurements I'm looking for.

Center of one mounting bolt to the other. I get 2.215" on the E30 caliper, but from what I'm seeing I'm fairly certain the MINI is different, so maybe I could use the E30 carrier with a MINI caliper. For that I need to know the distance from the center of one guide pin to the other. I measured this on the E30 by measuring from the outside of the pins and subtracting the diamter of one and came up with 2.967 inches with a 0.472 inch guide pin diameter. I'm also curious as to what the piston diameter is. E30s are 33mm/1.298", and I imagine the MINI's are a bit larger.

I'd also be interested in some specs of the R56 Cooper S/R53 JCW front calipers to see about upgrading to the 294x22 rotors those cars use as opposed to the E30's stock 260x22s.

Also, if anyone knows where I could simply buy some used MINI brake calipers on the cheap to have parts I could toy around with on the struts and trailing arms, that would be great.

If anyone can help me out, I'd really appreciate it. Thanks.

 

Except the difference in the rotors you posted, the E30 has a significantly taller rotor hat, where the offset is placed farther inboard.
That result changes clearances on both the caliper to the inside of the wheel, and the carrier mounting position of the caliper.
Just like with ANY brake caliper swap, it usually comes down to a carrier mount that's typically designed and fabricated by the end user.

It's certain that the E30 hubs and uprights don't use the same hardware or mounting pattern as the MINI R53 or R56 platform; especially being that brake bias on the E30 is different.

If you're wanting to tackle, I high suggest heading to a local MINI shop or dealer and see if you can pull hard dimensions for yourself since that's what you in need of.
Plus, you'll be able to see the difference in caliper design, mounting, and shear size...
That's not including the need for possible custom build brake lines or the like.

To me, it seems like a Willwood or other aftermarket brake kit may suit you needs / wants in a quicker and perhaps less time and cost expensive matter.

- Erik

 

I would also like to know the spacing on the bolts and alike. Firstly I think it is good information to have and for someone that might find a good caliper for chips one day he might want to have these dimensions handy.

anycase, on the E30, I know the fronts can be swapped for old 535i calipers which are 4 pot units and might be the best option. Otherwise it will be great to keep us or even just me in the loop of your progress.

Cheers

 

I haven't found anything on the guide pin spacing yet. I could try what bluefox said about heading to a shop or dealer for dimensions, but I live in Middle Tennessee where all anybody cares about is pick-up trucks. I do know that the rear uses a 34mm piston and the front a 54. 34 isn't really an upgrade for the rear, but MINI rear pad's backing plates have the exact dimensions as E36 pads, so it might be possible to make some combination of carrier/custom bracket , E36 caliper (38mm piston), and MINI pads work on the rear. As for the front, the deeper offset of the disc would be insanely close to the E30's tie rod ball joint and most likely not clear by an ever so slight margin by my measurements. They're might be a way to work around this, and I'd like to try fitting some old MINI rotors at some point, but I have a lot of other things to concentrate on with my E30 first. I made a thread about it here. http://www.e30tech.com/forum/showthread.php?t=111466 It got a little bit away from the original idea of the topic, but there's still a lot of good info in there.

Are E12 535i calipers 4-pot? I know E28 535i are one-piston since I drive one everyday. E28 M5s and E24 M6s use 4-pots, and the disc is the same as a 7-series disc, but I can't remember which exactly. E32 740iL maybe?