R1 Concepts Big Brake Kit Review

[uberschnell]

Originally Posted by WhatsADSM

OP:

I had to double check the piston area calculations on this and I agree. This most certainly moves brake bias considerably more forward (I show about 71.5% / 28.5% bias assuming the quoted 65/35 ratio was the correct stock number). Moving the ratio forward a little bit usually isn't a bad thing for a modified car but you may likely find that it is too far forward like this and as mentioned will probably increase overall stopping distance. If it gets to be too great you may have to tweak your compound selections front to rear to compensate (not ideal but will help), I believe the carbotech XP series compounds are available in that pad shape and have varying mu values (friction coefficient).

Another thought is that it is possible that R1 concepts designed this kit assuming that you would use their rear BBK with it which would likely shift the bias ratio closer to stock. Only issue with that is overall volume of caliper to master cylinder would be affected and would be decreased pedal feel and potentially the need to use too much pedal travel. Which means you might then need an upgraded master cylinder as well.

In any case it's always nice to have more brake options out there so I am happy to hear there is another product out there for the chassis. Thanks for the thorough review with all the pictures and the comparison to the high dollar brembo GT kit.

I am running different pads front and rear. In day to day driving the brake bias is negligible, that I can tell you from direct experience (in day to day driving). Even under emergency braking (rare) there are no negligible effects and stopping distance is as good as stock (and far better then most cars in front or behind me)

I've tracked cars so I understand the importance in brake bias under hard, consistent braking. I do think for moderate track use it would be important to upgrade front and rear (Which I did on my 335i and found no real issue with master cylinder being inadequate).

If i was going to spend moderate time on the track I would have gotten front and rear, gone with slotted and not drilled, and would have a separate set of track pads for track days.

As is, I have these more for appearance then track. The main point I want to share is that as an alternative to some of the more expensive brands these have worked very well in day to day driving, look good, and that I am surprisingly impressed with the performance.

I am tempted to go with the rears but am working through wheels and tire sizing right now ($$) as my car has custom offsets due to custom wide-body. Perhaps if R1 is willing to offer a deal then maybe sooner then later...?

[houtan]

Originally Posted by uberschnell

I am running different pads front and rear. In day to day driving the brake bias is negligible, that I can tell you from direct experience (in day to day driving). Even under emergency braking (rare) there are no negligible effects and stopping distance is as good as stock (and far better then most cars in front or behind me)

I've tracked cars so I understand the importance in brake bias under hard, consistent braking. I do think for moderate track use it would be important to upgrade front and rear (Which I did on my 335i and found no real issue with master cylinder being inadequate).

If i was going to spend moderate time on the track I would have gotten front and rear, gone with slotted and not drilled, and would have a separate set of track pads for track days.

As is, I have these more for appearance then track. The main point I want to share is that as an alternative to some of the more expensive brands these have worked very well in day to day driving, look good, and that I am surprisingly impressed with the performance.

I am tempted to go with the rears but am working through wheels and tire sizing right now ($$) as my car has custom offsets due to custom wide-body. Perhaps if R1 is willing to offer a deal then maybe sooner then later...?

you going to share info on the custom widebody? sounds awesome.

Also, will be nice to here what R1 has to say about brake bias impact by just doing the fronts, and any impacts on master cylinder performance.

[uberschnell]

Originally Posted by houtan

you going to share info on the custom widebody? sounds awesome.

Also, will be nice to here what R1 has to say about brake bias impact by just doing the fronts, and any impacts on master cylinder performance.

here is a quick shot, still working on tire sizes

[fe1rx]

Originally Posted by uberschnell

here is a quick shot, still working on tire sizes

Very nice ...

[houtan]

Originally Posted by fe1rx

Very nice ...

+1. That looks badass!

[connorfitz]

Originally Posted by uberschnell

here is a quick shot, still working on tire sizes

What rims are those also how much was this BBK? I’m looking to get a pair

[Traf]

Originally Posted by uberschnell

here is a quick shot, still working on tire sizes

I'm using 275/35r18 front and 295/35r18 rear on my 1M conversion 135i, probably gonna switch to 295/30r18 when i can.
It should be noted that i have M3 rear hubs.

[amg6975]

Originally Posted by uberschnell

here is a quick shot, still working on tire sizes

Wow, that looks great. The rear is stock?

[uberschnell]

Originally Posted by amg6975

Wow, that looks great. The rear is stock?

Yeah, the kit is 355 mm which is not a huge jump from stock. Haven't really had any issues with bias

[uberschnell]

Originally Posted by connorfitz

What rims are those also how much was this BBK? I’m looking to get a pair

Vorsteiner Flow Form. A little over 2K

[amg6975]

Originally Posted by uberschnell

Yeah, the kit is 355 mm which is not a huge jump from stock. Haven't really had any issues with bias

I was actually way off topic and referring to the 1M conversion. Stock 135 rear quarters? What are the wheel specs? Usually front only conversions look completely backwards of that looking at the concavity.

[Traf]

Full conversion including rear, i'm using Apex EC7 in:
18x9.5 ET22 275/35r18 MPSS
18x10.5 ET27 295/35r18 MPSS

I'd like to switch to 295/30r18 but i have a hard time finding a tire that is also available in 275/35r18.
Maybe this will help uberschnell decide

[uberschnell]

Originally Posted by amg6975

I was actually way off topic and referring to the 1M conversion. Stock 135 rear quarters? What are the wheel specs? Usually front only conversions look completely backwards of that looking at the concavity.

Originally Posted by Traf

Full conversion including rear, i'm using Apex EC7 in:
18x9.5 ET22 275/35r18 MPSS
18x10.5 ET27 295/35r18 MPSS

I'd like to switch to 295/30r18 but i have a hard time finding a tire that is also available in 275/35r18.
Maybe this will help uberschnell decide

I have the 1M rear quarters but 135i hubs which I think means they stick out 10mm more then real 1M. I'm running 285/30R19 in the rear now. Love how they look. Could do 295 but depends on brand, has to be one of the narrower ones to avoid rub.

[amg6975]

Originally Posted by uberschnell

I have the 1M rear quarters but 135i hubs which I think means they stick out 10mm more then real 1M. I'm running 285/30R19 in the rear now. Love how they look. Could do 295 but depends on brand, has to be one of the narrower ones to avoid rub.

Ah yeah, that's why it looks so good.

[Skrubway]

I am not able to PM the OP but I was wondering, if you see this, if you could help me determine fitment for my 135i. I was actually looking at picking up this BBK and could use the help! thanks

[r1concepts]

Originally Posted by Skrubway

I am not able to PM the OP but I was wondering, if you see this, if you could help me determine fitment for my 135i. I was actually looking at picking up this BBK and could use the help! thanks

Please email me at kevin@r1concepts.com and I will help you out.

[Skrubway]

Originally Posted by r1concepts

Please email me at kevin@r1concepts.com and I will help you out.

I actually have been emailing with a rep named Peace Phan. I was just trying to get ahold of the OP since hes the only 135i ive seen running these brakes. Ill definitely send you a email though!

[Slothfish]

OP...

It's been over 6 years, and multiple people have asked you how much you paid for this kit. We've been waiting. Is there a reason you won't answer?

[r1concepts]

One of the reps here from R1. A front and rear kit ranges between $4,300-$5,300 depending on what size wheels are on the car. Feel free to email me if you guys have any questions or would like an exact price quote kevin@r1concepts.com.