rotor cracks question

dt15 · Sat, Nov-29-2008, 09:20:01 PM

hi everyone,
i have a 2005 zcp and the rotors are showing hairline cracks (esp the fronts). i track the car twice a year with pfc01s and michelin psc tires. my dealer told me that they would not replace the rotors since bmw would likely find the nonbmw pad material on the rotors and not allow replacement based on the use of nonbmw pads.

is this reasonable or should i not accept this?

are the hairline cracks serious or no big deal?

THEHOUNDER · Sat, Nov-29-2008, 09:27:59 PM

are they through the rotor or just "crazing"?

BTW- BMWUSA is not CSI, and they have no way of telling what kind of pad material is on the rotor.

Mvez · Sat, Nov-29-2008, 10:11:03 PM

Quote:

Originally Posted by dt15

hi everyone,
i have a 2005 zcp and the rotors are showing hairline cracks (esp the fronts). i track the car twice a year with pfc01s and michelin psc tires. my dealer told me that they would not replace the rotors since bmw would likely find the nonbmw pad material on the rotors and not allow replacement based on the use of nonbmw pads.

is this reasonable or should i not accept this?

are the hairline cracks serious or no big deal?

Do yourself a favor and use some less abrasive pads....those things eat rotors.

jrf m3 · Sat, Nov-29-2008, 10:20:30 PM

Quote:

Originally Posted by Mvez

Do yourself a favor and use some less abrasive pads....those things eat rotors.

true, but they stop like a mofo

Subw00er · Sun, Nov-30-2008, 01:09:18 AM

This is normal with aggressive pads or not, pad hardness will just lengthen or shorten the time until it happens. The rule of thumb is that if no crack is within 1/2" from the outer edge, you are probably fine, especially on the street. I, however, would never go to a track event with cracks showing, change it before you go back. I'd usually get 4 days out of a set of rotors on a fast track.

About the pad material. Just run it with normal pads and do a bed in process, and they wont be able to tell. Thats dealer nonsense. Anyway, what is BMW going to do...? A chemical analysis on your rotor? The analysis would cost more than the rotor likely.

About warranty.. thats a tough one. When I bought my last bmw, I asked if BMW would cover my pads if they wore in 5K miles and they said yes (at least once anyway). My dealer is serious about the warranty $0-cost. I guess this is dealer specific.

98_1LE · Sun, Nov-30-2008, 02:36:34 AM

If you track the car, especially with aftermarket parts, you cannot really expect the dealer to pick up the tab for brakes.

Personally I prefer to have separate sets of front pads & rotors for street and track use, respectively.

If I were you, I would street drive with the minor cracks as long as there is no vibration, and replace the rotors before your next track day.

THEHOUNDER · Sun, Nov-30-2008, 11:24:41 AM

do you have a picture of the cracks on the rotors?

mmmpowr · Sun, Nov-30-2008, 04:55:28 PM

Just put some stock pads back in and run them for awhile before taking it in. Friends have always been able to get replacement rotors that way.

As for the cracks, it's had to know without see them. If the cracks are linking from hole to hole (euro rotors) or are at the edge, then they need to be replaced.

prematureapex · Thu, Dec-04-2008, 08:26:38 PM

Totally normal on a tracked car.

Commonly used rule: If you catch your fingernail on the crack, time for replacements.

They will grow larger in time, and eventually fail. I have a pile of failed rotors from various cars from not checking the hairlines for too long.

Mvez · Fri, Dec-05-2008, 12:22:50 AM

Here's a solution....floating, Slotted rotors for the ZCP. It's the only slotted direct replacement rotors I know of for the ZCP. Not cheap, but what is for this car.

I wonder why DBA hasn't made a 5000 series set for our car yet.

http://www.racingbrake.com/M3_E46_Co...p/2102-311.htm

Sat, Nov-29-2008, 09:20:01 PM	#1
dt15 Registered User Join Date: Oct 2003 Posts: 110 Reputation: 0	rotor cracks question hi everyone, i have a 2005 zcp and the rotors are showing hairline cracks (esp the fronts). i track the car twice a year with pfc01s and michelin psc tires. my dealer told me that they would not replace the rotors since bmw would likely find the nonbmw pad material on the rotors and not allow replacement based on the use of nonbmw pads. is this reasonable or should i not accept this? are the hairline cracks serious or no big deal?

Sat, Nov-29-2008, 09:27:59 PM	#2
THEHOUNDER Old Guy with M3 Join Date: May 2005 Posts: 2,043 Reputation: 0 Location: St. Charles, IL	are they through the rotor or just "crazing"? BTW- BMWUSA is not CSI, and they have no way of telling what kind of pad material is on the rotor. __________________ 2004 Silbergrau SMG/ FLMS "half cage"/ V-CSL Roof/Works Bell SMG/ Fabspeed Headers/ Epic tune/ BW 3.5"/Cobra Sebring (d) - Suzuka (p)/Brembo 355/345 / GSP Gen 1 Pedal /Moton CS / Ground Control Race Bars / AIM Solo DL /Other junk and stuff 2012 Mercedes GL450 - Tow pig 2010 Featherlite 17'6" open 2008 335xi -stock

Sun, Nov-30-2008, 02:36:34 AM	#6
98_1LE Registered User Join Date: Jun 2002 Posts: 332 Reputation: 0 Location: Dallas	If you track the car, especially with aftermarket parts, you cannot really expect the dealer to pick up the tab for brakes. Personally I prefer to have separate sets of front pads & rotors for street and track use, respectively. If I were you, I would street drive with the minor cracks as long as there is no vibration, and replace the rotors before your next track day. __________________ 1996 M3 coupe \| 2001 Trans Am

Sun, Nov-30-2008, 11:24:41 AM	#7
THEHOUNDER Old Guy with M3 Join Date: May 2005 Posts: 2,043 Reputation: 0 Location: St. Charles, IL	do you have a picture of the cracks on the rotors? __________________ 2004 Silbergrau SMG/ FLMS "half cage"/ V-CSL Roof/Works Bell SMG/ Fabspeed Headers/ Epic tune/ BW 3.5"/Cobra Sebring (d) - Suzuka (p)/Brembo 355/345 / GSP Gen 1 Pedal /Moton CS / Ground Control Race Bars / AIM Solo DL /Other junk and stuff 2012 Mercedes GL450 - Tow pig 2010 Featherlite 17'6" open 2008 335xi -stock

Sun, Nov-30-2008, 04:55:28 PM	#8
mmmpowr Registered User Join Date: Oct 2004 Posts: 905 Reputation: 0 Location: Farmington Hills, MI	Just put some stock pads back in and run them for awhile before taking it in. Friends have always been able to get replacement rotors that way. As for the cracks, it's had to know without see them. If the cracks are linking from hole to hole (euro rotors) or are at the edge, then they need to be replaced. __________________ David 2001 ///M3 OEM: 6-Speed \| Titanium Silver Metallic \| Imola Nappa Leather \| Power Seat Package \| Cold Weather Package \| Width adj. front seat with lumbar \| Xenon \| Moonroof \| In-dash CD \| HK \| BMW alarm \| Univeral transceiver Mods: OEM Strut brace \| OEM 19" wheels (street) \| RAC RS110 9.5"(f)/10"(r) wheels (track) \| Brembo 355(f)/345(r) BBK \| Motul RBF600brake fluid \| ACS rear shock tower brace \| D/A Race software \| SS Stepped Headers/S-pipe/X-pipe w/resonator/Race muffler \| RE pullies \| aFe CAI stg1 \| Bimmerworld intake elbow \| Bimmerworld CF brake ducts \| BMW Motorsport thermostat \| TCK D/A coilovers w/#600(f)/#700(r) \| GC camber/castor Race plate \| Powerflex FCAB \| GC front sway bar links \| h-Sport sway bars \| RE Tranny mounts \| TCK RTAB \| GC RLCA\| TCK shock mounts \| V-CSL CF trunk \| V-CSL CF diffuser \| McMahan 4pt rollbar \| TMS oil cooler \| RE Octane SSK

Sun, Nov-30-2008, 01:09:18 AM	#5
Subw00er Registered User Join Date: Oct 2008 Posts: 307 Reputation: 0 Location: NY	This is normal with aggressive pads or not, pad hardness will just lengthen or shorten the time until it happens. The rule of thumb is that if no crack is within 1/2" from the outer edge, you are probably fine, especially on the street. I, however, would never go to a track event with cracks showing, change it before you go back. I'd usually get 4 days out of a set of rotors on a fast track. About the pad material. Just run it with normal pads and do a bed in process, and they wont be able to tell. Thats dealer nonsense. Anyway, what is BMW going to do...? A chemical analysis on your rotor? The analysis would cost more than the rotor likely. About warranty.. thats a tough one. When I bought my last bmw, I asked if BMW would cover my pads if they wore in 5K miles and they said yes (at least once anyway). My dealer is serious about the warranty $0-cost. I guess this is dealer specific.

Thu, Dec-04-2008, 08:26:38 PM	#9
prematureapex Registered User Join Date: Mar 2008 Posts: 851 Reputation: 0	Totally normal on a tracked car. Commonly used rule: If you catch your fingernail on the crack, time for replacements. They will grow larger in time, and eventually fail. I have a pile of failed rotors from various cars from not checking the hairlines for too long.

Fri, Dec-05-2008, 12:22:50 AM	#10
Mvez RS-aholic Join Date: Jul 2005 Posts: 2,034 Reputation: 0 Location: KY	Here's a solution....floating, Slotted rotors for the ZCP. It's the only slotted direct replacement rotors I know of for the ZCP. Not cheap, but what is for this car. I wonder why DBA hasn't made a 5000 series set for our car yet. http://www.racingbrake.com/M3_E46_Co...p/2102-311.htm __________________ 2007 GT3RS - Guard 40/60 LSD \| GMG sway bars \| Swift race springs \| Cup toe links \| Factory Clubsport Rollbar and Seats \| Wevo Engine Mounts \| Studs \| CCW C14 wheels \| Schroth \| 2005 M3 Coupe - GC Race/Track S/A \| ERS 700#F, 800#R \| Turner Bars \| Turner Subframe F/R Reinforcements \| RE RTABs \| RE Rear Control Arms \| RE Engine Mounts \| RE Tranny mounts \| TreeHouse Racing FCABs \| AKG Rear Subframe Bushings (75D) \| GC Camber Plates \| GC Weight Jackers \| Clutchmaster Stage 1 \| OEM CSL headers \| SS Section 1 w/ High flow cats \| Dinan CAI \| Dinan Stage 3 software \| Dinan SSK \| AA Exhaust (Gen 3) \| Bimmerworld Intake Elbow \| Turner Oil Cooler Kit \| Stoptech ST-40, 355F \| ZCP Rear w/ bushing upgrade \| SS Lines \| ARC-8 9.5"F, 10"R \| Turner Studs \| Turner Racing Pedals \| Raven 4pt. Rollbar \| Schroth \| Braille B3121 \| No sunroof \| '04 X5 4.4i

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