How cracked is too cracked?

M2guru · 05-03-2022, 05:00 PM

Debating if these are too far gone for one track day that doesn't have sessions. Thoughts?

Suds · 05-03-2022, 05:54 PM

That rotor is just getting broken in.
Rotors are done when a crack goes between two holes or from a hole to the edge of the rotor.

These are cooked! AP Racing for reference.

M2guru · 05-03-2022, 06:07 PM

Quote:

Originally Posted by Suds

That rotor is just getting broken in.
Rotors are done when a crack goes between two holes or from a hole to the edge of the rotor.

I will post a pick up when I get home.

Thanks for your thoughts. I'll probably save the hassle of trying to cram my spare set in my tow-behind trailer.

///MPhatic · 05-03-2022, 06:22 PM

Quote:

Originally Posted by Suds

That rotor is just getting broken in.
Rotors are done when a crack goes between two holes or from a hole to the edge of the rotor.

I will post a pick up when I get home.

I agree with this. Much more life in these rotors.

dvas · 05-03-2022, 06:57 PM

Those rotors are fine, good for many more days. Micro cracks such as on the pictured rotors are a non-issue. You will eventually see real cracks developing.

DRLane · 05-03-2022, 07:47 PM

As already mentioned, once the cracks persistently reach the edge is when I retire the ring.

///MPhatic · 05-03-2022, 08:14 PM

This is a rotor from a tracked Exige. This is about the point where the Lotus guys replace them.

DRLane · 05-03-2022, 08:29 PM

If you're tracking a lot, avoid the drilled rotors. Better off with a smooth face vs drilled.

If you're sticking with OEM via FCP Euro warranty replacements, then carry on!

5.M0NSTER · 05-04-2022, 07:49 AM

Oh yeah, plenty of life left in those

M2guru · 05-04-2022, 07:55 AM

Quote:

Originally Posted by DRLane

If you're tracking a lot, avoid the drilled rotors. Better off with a smooth face vs drilled.

If you're sticking with OEM via FCP Euro warranty replacements, then carry on!

Check!

GasBurnlife(landapanda) · 05-04-2022, 06:18 PM

When the cracks get close to the edge, you will need to monitor them closely. Replace once the crack touches the outer or inner edge. Get your rotors from FCPEuro for free lifetime replacement!

3LiterBeater · 05-04-2022, 08:06 PM

I feel it may help, I ran my rotors for 17 days at relatively high-speed tracks. This was on day 17 and I ran them without issue.

Many are reporting even more days than I've experienced but I assume that is due to not driving the car in winter and using a more friendly pad compound.

The Apex ring taxi guys state these rotors are the way to go on the M2 and M4. They're cheap-ish and wear very well, even considering their drilled. I bought another set of OEM for $500 on FCP.

Rears look good as new

05-03-2022, 05:00 PM	#1
M2guru Lieutenant 384 Rep 573 Posts Drives: 2018 M2 Join Date: May 2017 Location: St. Paul MN iTrader: (2) Garage List 2018 BMW M2 [10.00]	How cracked is too cracked? Debating if these are too far gone for one track day that doesn't have sessions. Thoughts? Attached Images
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05-03-2022, 05:54 PM	#2
Suds /M Enthusiast 1599 Rep 1,619 Posts Drives: Responsiblish Join Date: Aug 2010 Location: Lone Star State iTrader: (1)	That rotor is just getting broken in. Rotors are done when a crack goes between two holes or from a hole to the edge of the rotor. These are cooked! AP Racing for reference. Attached Images __________________ 2019 M2 Comp, Alpine White, DCT, track car build, 1/2 cage, AP Racing Brakes & Nitron Coilovers, BM3 Stage 1 93 Oct. 2018 Porsche Cayman GTS, Night Blue Metalic, PDK, COBB tuned 93 Oct. 2004 Audi A4 Avant USP 6mt, RS4 clutch, built motor, Garrett GT3071r "Big Ass Turbo" Motoza Tune Last edited by Suds; 05-03-2022 at 07:54 PM..
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05-03-2022, 06:57 PM	#5
dvas Lieutenant 518 Rep 582 Posts Drives: 2017 M2 - Mineral Gray, 6spd Join Date: Jul 2014 Location: NYC iTrader: (0)	Those rotors are fine, good for many more days. Micro cracks such as on the pictured rotors are a non-issue. You will eventually see real cracks developing. __________________ 2017 BMW M2 5Spd, 2007 VW Touareg, 2023 Yamaha MT09 SP https://www.instagram.com/dvas99/ https://www.youtube.com/channel/UC2j..._as=subscriber
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05-03-2022, 07:47 PM	#6
DRLane Brigadier General 3989 Rep 3,409 Posts Drives: E92 M3 Join Date: Oct 2018 Location: Colorado iTrader: (21) Garage List 2008 m3 [6.63]	As already mentioned, once the cracks persistently reach the edge is when I retire the ring. Attached Images __________________ Not a Doctor, those are just my initials.
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05-03-2022, 08:14 PM	#7
///MPhatic The Seeker 13863 Rep 3,323 Posts Drives: OG M2 • Exige Join Date: Aug 2008 Location: USA iTrader: (2)	This is a rotor from a tracked Exige. This is about the point where the Lotus guys replace them. Attached Images
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05-03-2022, 08:29 PM	#8
DRLane Brigadier General 3989 Rep 3,409 Posts Drives: E92 M3 Join Date: Oct 2018 Location: Colorado iTrader: (21) Garage List 2008 m3 [6.63]	If you're tracking a lot, avoid the drilled rotors. Better off with a smooth face vs drilled. If you're sticking with OEM via FCP Euro warranty replacements, then carry on! __________________ Not a Doctor, those are just my initials.
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05-04-2022, 07:49 AM	#9
5.M0NSTER Lieutenant Colonel 3354 Rep 1,823 Posts Drives: 2018 Camaro SS 1LE Join Date: Dec 2018 Location: Back in Michigan, GO BLUE! iTrader: (0)	Oh yeah, plenty of life left in those
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05-04-2022, 06:18 PM	#11
GasBurnlife(landapanda) Captain 576 Rep 684 Posts Drives: BMW M2 Join Date: Aug 2012 Location: Ashburn, Virginia iTrader: (0)	When the cracks get close to the edge, you will need to monitor them closely. Replace once the crack touches the outer or inner edge. Get your rotors from FCPEuro for free lifetime replacement!
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05-04-2022, 08:06 PM	#12
3LiterBeater Second Lieutenant 130 Rep 221 Posts Drives: BMW M2, Porsche 944 Turbo Join Date: Dec 2020 Location: Maryland iTrader: (0)	I feel it may help, I ran my rotors for 17 days at relatively high-speed tracks. This was on day 17 and I ran them without issue. Many are reporting even more days than I've experienced but I assume that is due to not driving the car in winter and using a more friendly pad compound. The Apex ring taxi guys state these rotors are the way to go on the M2 and M4. They're cheap-ish and wear very well, even considering their drilled. I bought another set of OEM for $500 on FCP. Rears look good as new Attached Images
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