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      04-29-2019, 11:53 PM   #1
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Alternative m2c front rotors?

any aftermarkets rotors available? preferably slotted.
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      04-30-2019, 12:12 AM   #2
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I just emailed girodisc since they are close by maybe they can use my m2c for r&d. I'll update with their response.
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      05-02-2019, 02:30 PM   #3
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Quote:
Originally Posted by OGM2C View Post
any aftermarkets rotors available? preferably slotted.
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      05-02-2019, 03:15 PM   #4
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Quote:
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Originally Posted by OGM2C View Post
any aftermarkets rotors available? preferably slotted.
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Good news! Girodisc just started work on this.

They may use my m2c to test fitment so I'll let folks know when I know more.
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      05-03-2019, 12:49 AM   #5
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Silly question but aren't the M2C rotors same as OG M2 rotors?
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      05-03-2019, 03:51 AM   #6
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Originally Posted by 5.M0NSTER View Post
Silly question but aren't the M2C rotors same as OG M2 rotors?
If you have standart brakes they are same as on OG M2, if you have optional brakes, they are different (in US I think that optional brakes are in standart)

OG M2 / M2C with standart brakes:
Front rotors 380x30mm
Rear rotors 370x24mm

M2C optional brakes:
Front rotors 400x36mm
Rear rotors 380x28mm
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      05-03-2019, 03:52 AM   #7
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Quote:
Originally Posted by OGM2C View Post
Good news! Girodisc just started work on this.

They may use my m2c to test fitment so I'll let folks know when I know more.
Great, let me know
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      05-27-2019, 12:35 PM   #8
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Bumping this thread - any more info from girodisc or others about a slotted replacement front rotor for the M2C? Thanks!!
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      06-20-2019, 07:40 AM   #9
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Quote:
Originally Posted by hd-mastiff View Post
Bumping this thread - any more info from girodisc or others about a slotted replacement front rotor for the M2C? Thanks!!
Ordered set from racingbrake.com hope it will work and 380x36 is enough plus I can fit any 19" wheels and might fit some 18"
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      06-25-2019, 04:59 AM   #10
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Go rdd...lighter too

https://f87.bimmerpost.com/forums/sh....php?t=1535803
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      06-25-2019, 11:54 AM   #11
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Quote:
Originally Posted by Karmic Man View Post
RDD front rotors 400x36 12,9 kg (28,4 lbs)
RacingBrake front rotors 380x36 11,8 kg (26,0 lbs)

I dont see where its lighter
Plus I can fit any 19 wheels and might fit also some 18 plus I can fit real semi-metalic track pads
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      06-25-2019, 12:08 PM   #12
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Quote:
Originally Posted by Karmic Man View Post
Unfortunately, the RDD rotors are extremely expensive

I am very much hoping Girodisc comes through with a high quality and reasonably priced alternative for the M2C
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      06-27-2019, 03:03 AM   #13
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Quote:
Originally Posted by Vojta89 View Post
RDD front rotors 400x36 12,9 kg (28,4 lbs)
RacingBrake front rotors 380x36 11,8 kg (26,0 lbs)

I dont see where its lighter
Plus I can fit any 19 wheels and might fit also some 18 plus I can fit real semi-metalic track pads
Lighter than stock was what I meant as they are the same size as the M2C BBK. The context of my reply should be plain obvious
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      07-10-2019, 03:54 AM   #14
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Quote:
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Ordered set from racingbrake.com hope it will work and 380x36 is enough plus I can fit any 19" wheels and might fit some 18"
Umm why buy these discs?

If you have the 2NH option (which you need as these disks are seemingly designed for the 6 piston brakes and not the 4 piston brakes) then these discs will do very little but be lighter because they are smaller (400 vs. 380mm dia).

They also won't let you run 18s as the caliper will still be in the same place and this is what limits the wheel dia sizes.

If you track your money would be better spent on fluid, pads, and brake cooling (revzo sport or BP engineering for example) than these disks.

Also RBs high temp dust boots are not worth it. I did it to my previous car and they started cracking after the 3rd track day (could be due to the OEM pads having sticky backings though).
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      07-11-2019, 07:02 AM   #15
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Quote:
Originally Posted by Megator View Post
Umm why buy these discs?

If you have the 2NH option (which you need as these disks are seemingly designed for the 6 piston brakes and not the 4 piston brakes) then these discs will do very little but be lighter because they are smaller (400 vs. 380mm dia).

They also won't let you run 18s as the caliper will still be in the same place and this is what limits the wheel dia sizes.

If you track your money would be better spent on fluid, pads, and brake cooling (revzo sport or BP engineering for example) than these disks.

Also RBs high temp dust boots are not worth it. I did it to my previous car and they started cracking after the 3rd track day (could be due to the OEM pads having sticky backings though).
With these discs from RacingBrakes.com you are getting another adapters for calipers, that means it moves inside and you can fit some 18" (not many, but some). And tell me more about that how you need 400 mm dia discs in front on car like M2 Comp... Thickness is much more interesting. If you dont have 2NH option, you get 380x30 and you can fit some 18" wheels, I have 2NH option and with Racingbrakes rotors in size 380x36 I have higher thickness, better caliper and can fit 18" wheels, what do you need more, it has just pluses? And if I won't be happy with rotors from RB, I can get 380x36 from my producer of rotors (who supplied me for my last track car), who doesnt have 400mm available

Fluid, pads and lines already solved, only problem was with pads, because I wasnt that happy with Endless ME20, which most of people are finding hardcore, but stock rotors would crack as a nut with brake pads i wanted, so I hope I can use them with RB rotors and can get rid of ME20, which are the max you can use with stock drilled rotors

Better cooling of brakes is not necessary right now, it's not overheating, will see in the future. BTW BP or similar under car cooling is not needed for M2comp, because it has straight pipes to wheel arch / wheel trims (dont know how it's called), you just have to put brake disc duck and a flexi hose, nothing more.
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      07-11-2019, 08:33 AM   #16
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The 2NH disk is 400x36 and the RB is 380x36, the RB disc is smaller and therefore should naturally be lighter. This is the only point I made. I never commented on the issues you raise.

From the RB website it was not clear that new brackets were supplied but it makes sense.

The 2NH and STD calipers suffer from the same problem, they have dust boots that will perish if you really push the car hard. Also how do you ascertain that the 2NH caliper is better than the standard caliper?

I had ME20s on my RS and have a set for the M2C, will see how they do. I want the Essex AP kit for my car so the std brakes only need to last 2 years

I know the M2C has brake cooling ducts, the Q is how effective they are (and this is a forum for M2s as well). I still have not received my M2C so have had no chance to look. I will do ducting to the brakes ASAP.
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      07-12-2019, 10:40 PM   #17
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Good news! Girodisc prototype rotor fits - double the veins, approximately the same weight as OEM.

Girodisc just moved to a larger facility which has temporarily slowed down production, they estimate approx. 3-4 weeks till production units are available.
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      07-15-2019, 08:11 AM   #18
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Quote:
Originally Posted by Megator View Post
The 2NH disk is 400x36 and the RB is 380x36, the RB disc is smaller and therefore should naturally be lighter. This is the only point I made. I never commented on the issues you raise.

From the RB website it was not clear that new brackets were supplied but it makes sense.

The 2NH and STD calipers suffer from the same problem, they have dust boots that will perish if you really push the car hard. Also how do you ascertain that the 2NH caliper is better than the standard caliper?

I had ME20s on my RS and have a set for the M2C, will see how they do. I want the Essex AP kit for my car so the std brakes only need to last 2 years

I know the M2C has brake cooling ducts, the Q is how effective they are (and this is a forum for M2s as well). I still have not received my M2C so have had no chance to look. I will do ducting to the brakes ASAP.
As almost every stock brake calipers, there are those on edge outside dusters (not sure how it's called in english), you have to change them if you track your car, most of aftermarket calipers have inner dusters (o-rings?), which are more far from the heat from brake pad, but you have to re-seal them also (done that once on my E46 BBK) just not that often.

2NH caliper is definitely better, because it can fit 36 mm thickness of rotors with cca 18mm pads, STD calipers can fit 30 mm rotors plus 18 mm pads... if you don't see why it's better

I already done 2 sets of ME20s on my M2comp and a standart set which was supllied with car. ME20s are not bad, but I want more, I was driving many years on RayBestos pads, which were just awesome

AP or other BBK is always the best way (not sure if I can call it BBK, here it should be SBK = smaller brake kit), but it's about money... you pay 4 times more for AP kit than I pay for this rotors... it was easiest way for me, will se how it will work, might end up with some BBK too.

Ducting for brakes straight to the center of rotors is great for strict track car (have it on my E46), but I use M2comp all the year on all the surfaces and in all weather and you don't want to have rock debris in the center of your rotors... When I will feel that it's overheating, than I will try to fit it somehow, but the main track I'm visiting is Nordschleife and it's not very hard for brakes there
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      07-16-2019, 11:34 PM   #19
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Thanks for the update

A little disappointed that they don't weight less than than the OEM rotors, but the extra cooling and the slotted design will still be welcome improvements

Will they also be doing rear rotors?



Quote:
Originally Posted by OGM2C View Post
Good news! Girodisc prototype rotor fits - double the veins, approximately the same weight as OEM.

Girodisc just moved to a larger facility which has temporarily slowed down production, they estimate approx. 3-4 weeks till production units are available.
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      07-18-2019, 03:58 AM   #20
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Quote:
Originally Posted by Vojta89 View Post
As almost every stock brake calipers, there are those on edge outside dusters (not sure how it's called in english), you have to change them if you track your car, most of aftermarket calipers have inner dusters (o-rings?), which are more far from the heat from brake pad, but you have to re-seal them also (done that once on my E46 BBK) just not that often.

2NH caliper is definitely better, because it can fit 36 mm thickness of rotors with cca 18mm pads, STD calipers can fit 30 mm rotors plus 18 mm pads... if you don't see why it's better

I already done 2 sets of ME20s on my M2comp and a standart set which was supllied with car. ME20s are not bad, but I want more, I was driving many years on RayBestos pads, which were just awesome

AP or other BBK is always the best way (not sure if I can call it BBK, here it should be SBK = smaller brake kit), but it's about money... you pay 4 times more for AP kit than I pay for this rotors... it was easiest way for me, will se how it will work, might end up with some BBK too.

Ducting for brakes straight to the center of rotors is great for strict track car (have it on my E46), but I use M2comp all the year on all the surfaces and in all weather and you don't want to have rock debris in the center of your rotors... When I will feel that it's overheating, than I will try to fit it somehow, but the main track I'm visiting is Nordschleife and it's not very hard for brakes there
Thanks for the discussion

I dont consider what you are saying the caliper being "better" I meant more like is it stiffer, does it offer more linear braking, more temp resistant.

I would have chosen 2NH but no 18s (although the tire choice in 18s for rear is not great), pad change is lame (for going from street to track), and dust boots just like any OEM caliper (dust boot goes outside and piston seal goes inside )

Damn 3 sets of pads already! How many track KM do you have??? I finally get my M2C tomorrow. I hope that I can get the brake in done in July and have it on track August.

My thinking was that 2NH + 2 piece discs + race pads was about the same price as Alcon 6/4 pots or AP front BBK. This also benefits the weight

I will add plugs to my ducts in order to block them for road use. I have a 3D printer and cant wait to fab some stuff up!
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      07-18-2019, 08:25 AM   #21
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Quote:
Originally Posted by Megator View Post
Thanks for the discussion

I dont consider what you are saying the caliper being "better" I meant more like is it stiffer, does it offer more linear braking, more temp resistant.

I would have chosen 2NH but no 18s (although the tire choice in 18s for rear is not great), pad change is lame (for going from street to track), and dust boots just like any OEM caliper (dust boot goes outside and piston seal goes inside )

Damn 3 sets of pads already! How many track KM do you have??? I finally get my M2C tomorrow. I hope that I can get the brake in done in July and have it on track August.

My thinking was that 2NH + 2 piece discs + race pads was about the same price as Alcon 6/4 pots or AP front BBK. This also benefits the weight

I will add plugs to my ducts in order to block them for road use. I have a 3D printer and cant wait to fab some stuff up!
I don't have direct track comparison of STD caliper and 2NH caliper, so I cannot compare those things you are asking.. it should have more heat resistance, because there is more brake fluid in them

There are many semi-slick tires, that are produced up to 18" and not bigger, that is my concern, for example Dunlop Direzza 03G, which is great semi-slick tire BTW thanks for the info how it's called in english (dust boot and piston seal)

I'm not really counting track kilometers, have my M2C since September 2018, I did brake in service in October and did one visit of Nordschleife+GP in November (cca 15 laps), than 9x20 minutes on Autodrom Most in end of March 2019, 5x30 minutes on Salzburgring in the beggining od April, 6x20 minutes on Nurburgring GP + 3 laps on Nordschleife in the beggining od May 2019, 18 laps on Nordschleife in June and 5x20 minutes on Bilster Berg... Stock pads were done after first visit of Nordschleife, first set of ME20s was done after Salzburgring and last set od ME20s is done now.... Waiting for new pads, but need some, so my friend provided me his MX72 set of brake pads and I hope it will be usable on track.... My brake pads are now in LA on the way to my adress to CZ

3D printer in not what I can work with I have to buy things that is someone producing

Thank you too for good discussion and let me know how you solved your brake system, I'll post here how RB rotors are working in track use
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      10-17-2019, 07:55 PM   #22
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Will the 380mm racing brake rotors used with the 6 piston 2NH caliper allow for an 18" wheel to be used?
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