Hello everyone, just a (hopefully) quick one for you today.

I'm trying to determine if I could save some money on a JCW brake swap for my S if I were to just do the front caliper swap (and master cyl/booster). I know I could, in theory, just run it with the S rear brakes and it would be fine, but a certain amount of perfectionist syndrome kicks in when I say that to myself.

I've exhausted all the leads that I know of, even checked RealOEM. I'm having a hard time determining if there's any real difference between the calipers on the rear between the two, beyond the paint color. Some sources suggest that the rear of the JCW might have slightly bigger and/or ventilated rotors, instead of the solid ones on the S, but every full swap kit I can find just comes with new solid rear rotors for the back and red painted calipers.

So my question is, are the rear calipers any different beyond the red paint, and does the JCW have different rotors in the rear from the S? If the calipers are the same, but the rotors are different, am wrong to assume I can just get JCW rotors along with my full front brakes and have a JCW brake kit minus the red paint in the back?

 

F54 S rear discs 280x10 unvented

F54 JCW pre-LCI 300x20 vented

You can source 16-20 X1, X2 or JCW F54 or F60 pre-LCI rear Calipers lor the swap all the same. F56 will not work due to non electric parking brake

Pads are the only common part on the rear S pads work with JCW.

Running full X2 brakes on my 2017 F54 S ALL4 ATM

330 front 300 rear.

EBC Yellow

Looking to swap up to pre-LCI 335 JCW fronts

 

So I see you found the same info I did on RealOEM about the differences between discs. Are you sure the calipers are different besides the pads? I guess that might be a stupid question, theoretically they would have to sit out further from the hub to clear the bigger rotor.

When you say you can use X1 or X2 calipers, I assume you mean the M-Sport ones?

 

The caliper mounting ears on the JCW (X1,X2) are just a bit longer so the caliper sits out farther from the hub center allowing the 300mm disc. Caliper is also a bit wider front to back to allow for thicker disc.

Non M Sport rear calipers for X1, X2 equal the JCW rear. It’s single piston. I picked mine up on EBay from a totaled 2020 X2, 80$ for the pair.

In theory we could run M Sport brakes from X? with the right size and offset wheels.

I like my 17” wheels and my poor man’s BBK.

 

You don't happen to know if we could swap the JCW BBK from an LCI car to a Pre-LCI car do you? I'm finding it a lot easier to find used calipers from LCI cars for some reason. They look a little different, have different part numbers, but I can't imagine Mini changed the mounting placement and brake line length/size. I'm also seeing it looks like they might be 330 in the front instead of 300.

 

Yep you can definitely run F54 LCI JCW brakes on pre-LCI F54 as long as you run at least 18” wheels.

 

That's awesome. That means I can get M235i GC calipers so I can have blue instead of red.

Last questions for you, are the rear carrier brackets for the calipers the same for Non-JCW and JCW, and it's just the calipers are different? Or are the carrier brackets different too? Do you happen to know if the EPB motor on the LCI is different from the Pre-LCI?

Do you know if a booster/master cylinder upgrade is really necessary for the F54 brake swap?

If you wouldn't mind, I'm wondering if these would work for the rear, without having to get the carrier brackets:

https://www.ebay.com/itm/276439788234?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=XBl0e3-WTUS&sssrc=4429486&ssuid=d_LSPPIzSRe&var=&widget_v er=artemis&media=COPY