[BasdeWit]

Hello all,

Last weekend I bought me a set of M sport brakes of the front side (340mm) from a M235i. Its an as good as new set as the owner got his car for track racing and he immediately replaced the front brakes.

I am planning to replace my brakes, a 125i f20 2012 with m sport kit, however with the standard grey brakes. I am wondering about two things:

1. will I be fine just replacing the front brakes (calipers, pads, disks), or MUST I also replace the rear with the blue m sport set? I have read on some forum threads that only front is fine too
2. will it fit with my OEM 17' wheels? Style 383.

If anyone could help me out on this I would be thankful!

[No one]

Hello.

Originally Posted by BasdeWit

1. will I be fine just replacing the front brakes (calipers, pads, disks), or MUST I also replace the rear with the blue m sport set?

You must have the complete set (that's properly matching brakes all around: all M Sport or all not M Sport), otherwise you'll have a severe braking imbalance! You also need the proper master cylinder and servo unit. Also, it looks likely you'll need to code your car for the braking system change: it's not just colour, M Sport brakes are more "grippy".

Originally Posted by BasdeWit

2. will it fit with my OEM 17' wheels? Style 383.

Yes it will.

[ovekvam]

I would have installed the front brakes to see if it upsets the braking balance before byuing the rest of the kit. Preferably test hard braking in a corner on a track first, to see if it is close enough. You could be lucky. If the front brakes are more grippy, it is also possible to compensate with grippier rear brake pads.

Most likely it will not work so well, but at least then you know, and it is not so much work to build it back.

[No one]

I wouldn't take the risk of crushing the car to find out the manufacturer's engineers can be trusted to have performed the necessary tests. "Experience is a good school, but only fools don't study elsewhere." Take a closer look at the M Performance brakes, just for example: notice that only the complete kit is suggested for retrofitting and the separate front/rear pairs are explicitly "For replacement/repair only, not suitable for retrofitting as brake kit!". You've been warned, at least.

Also, don't forget the DSC makes use of the brakes and it's probably tuned with certain assumptions.

You can play on a race track, that's what it's for , but don't take those games out onto public roads.

[dizx]

I am considering to upgrade the brakes on my 2013 F20 116i to the M Performance breaks. They are available 2nd hand at a price that makes it worth it.

Anyway, according to this thread, I need to replace the master cylinder and servo unit. I've read other threads that don't mention this. I've checked the prices for these two parts, and they seem quite expensive.

So basically I would like to know what will be the result if I retrofit the breaks, do the coding, and keep the stock master cylinder and servo unit?