Cracked rotor?

SonnyJack · 03-07-2020, 12:23 PM

Heading down to VIR in a few weeks and just discovered this. Looks cracked to me. Anyone disagree? Once I replace all four (nice way to start the season) is there anything other than bedding the brakes/rotors before heading south?

Welcome suggestions on replacement rotors. I'm assuming slotted?

SJ

roastbeef · 03-07-2020, 12:36 PM

For oem sizes, pfc has a great offering. I would also take a look at stop tech's slotted rotor.

SonnyJack · 03-07-2020, 01:50 PM

Quote:

Originally Posted by roastbeef

For oem sizes, pfc has a great offering. I would also take a look at stop tech's slotted rotor.

Much appreciated!

SYT_Shadow · 03-07-2020, 02:07 PM

Quote:

Originally Posted by roastbeef

For oem sizes, pfc has a great offering. I would also take a look at stop tech's slotted rotor.

This

The pfc dd front rotor for the e9x is a force to be reckoned with. Extremely track worthy

SonnyJack · 03-07-2020, 04:51 PM

Quote:

Originally Posted by SYT_Shadow

This

The pfc dd front rotor for the e9x is a force to be reckoned with. Extremely track worthy

Thanks!

Secondary question: These rotors were only 3 yrs old w/two track seasons. So, is that normal wear or did my change to the more aggressive StopTech SR34 pad cause this?

SYT_Shadow · 03-07-2020, 04:53 PM

Quote:

Originally Posted by SonnyJack

Thanks!

Secondary question: These rotors were only 3 yrs old w/two track seasons. So, is that normal wear or did my change to the more aggressive StopTech SR34 pad cause this?

stock rotor can't take heat. On a GTS we cracked M2C rotors which are 400mm and cool much better than E9X rotors in very little time.

Get the PFC rotor... if you want to maintain stock brakes there is no way around the PFC.

The pad for sure had something to do with it... you won't see me use a pad other than PFC11, but many other fast drivers use different things

admranger · 03-07-2020, 07:13 PM

PFC DD rotors are excellent. Had them all around on the E46M3. Tried some Chinese aftermarket floating rotors on the E90M3 and trashed them at COTA. On street tires. Junk.

COTA and Laguna Seca are both hard on brakes. I went to Laguna after COTA on my stock rotors, this time on NT-01’s. No issues. Those same rotors were used at Summit Point a couple years and thousands of miles (including the cross country drive to get from Vegas to DC).

PFC or StopTech I think are your options.

How much rotor is left on the stock rotor (thickness)? Age is irrelevant. Miles are irrelevant. Thickness is what matters. More heat sink available.

And yeah, the rotors in the pic are toast. To be sure, use the float test.

SonnyJack · 03-08-2020, 02:48 PM

Quote:

Originally Posted by admranger

PFC DD rotors are excellent. Had them all around on the E46M3. Tried some Chinese aftermarket floating rotors on the E90M3 and trashed them at COTA. On street tires. Junk.

COTA and Laguna Seca are both hard on brakes. I went to Laguna after COTA on my stock rotors, this time on NT-01’s. No issues. Those same rotors were used at Summit Point a couple years and thousands of miles (including the cross country drive to get from Vegas to DC).

PFC or StopTech I think are your options.

How much rotor is left on the stock rotor (thickness)? Age is irrelevant. Miles are irrelevant. Thickness is what matters. More heat sink available.

And yeah, the rotors in the pic are toast. To be sure, use the float test.

Thanks!

Ordered the StopTechs. As soon as I can find my measuring tool I'll report on thickness.

03-07-2020, 12:23 PM	#1
SonnyJack Captain 326 Rep 872 Posts Drives: '09 E92 M3/'18 F83 M4 Join Date: May 2010 Location: Laurel, MD iTrader: (1)	Heading down to VIR in a few weeks and just discovered this. Looks cracked to me. Anyone disagree? Once I replace all four (nice way to start the season) is there anything other than bedding the brakes/rotors before heading south? Welcome suggestions on replacement rotors. I'm assuming slotted? SJ Attached Images __________________ AA Gen 2 Lvl 2 w/Meth; MagnaFlow catless x-pipe; Dinan Underdrive Pulley; VAC Coated Bearings; ARP Rod Bolts; Oil Diverter Valve; Dinan Strut Braces; Dinan Rear Toe Links; ECS Rear Trailing Arms; MCS 2-Way NR w/700F-1000R; GC Camber Plates; AKG 75D MM & 95A TM; CAE Shifter; Titan T-S5; StopTech ST60 380mm/ST40 355mm; MFactory DS; Zebulon Splitter; Zebulon 330 Rear Wing; Gutted w/Piper Motorsports Custom Cage; OMP WRC-R Seats
	Appreciate 0 Tweet Quote

03-07-2020, 12:36 PM	#2
roastbeef Lieutenant General 11582 Rep 12,722 Posts Drives: E92 M3 Join Date: Nov 2010 Location: Orange County, CA iTrader: (4)	For oem sizes, pfc has a great offering. I would also take a look at stop tech's slotted rotor. __________________ Instagram; @roastbeefmike
	Appreciate 2 SonnyJack326.00 daarts38.50 Quote

03-07-2020, 07:13 PM	#7
admranger Retired Curmudgeon 2985 Rep 4,047 Posts Drives: ‘19 X3M40i, ‘18 m550i Join Date: May 2011 Location: Las Vegas, NV iTrader: (1)	PFC DD rotors are excellent. Had them all around on the E46M3. Tried some Chinese aftermarket floating rotors on the E90M3 and trashed them at COTA. On street tires. Junk. COTA and Laguna Seca are both hard on brakes. I went to Laguna after COTA on my stock rotors, this time on NT-01’s. No issues. Those same rotors were used at Summit Point a couple years and thousands of miles (including the cross country drive to get from Vegas to DC). PFC or StopTech I think are your options. How much rotor is left on the stock rotor (thickness)? Age is irrelevant. Miles are irrelevant. Thickness is what matters. More heat sink available. And yeah, the rotors in the pic are toast. To be sure, use the float test. __________________ '19 X3 M40 Carbon Black/Oyster, '23 Jeep Grand Cherokee L Summit, Past BMWs: '18 M550i, '18 330 GT, '16 X5 40e, '11 E90M3, '06 X5 4.4, '03 330i ZHP, '02 M3, '97 Z3 2.8, '95 M3 (2x), '94 530i (manual), '92 525i (manual), '88 M3, '87 325iS
	Appreciate 2 SonnyJack326.00 SYT_Shadow11468.50 Quote