Slots and Dimples disappeared on M Perf rotor...

Insane435 · 10-14-2018, 06:15 PM

How is this possible? Are they just that worn down? Also, my pads look like they have nothing left after 2 track days and 3 months of driving. Anyways, i did not think the slots and dimples could disappear. Can i still drive this thing or do i need to replace ASAP?

You can see how it had the slots and dimples at one point.

Grooves gone.

Pad wear.

Billfitz · 10-14-2018, 07:00 PM

I can almost guarantee that your rotors are less than minimum acceptable thickness.

Logicoeur · 10-14-2018, 07:22 PM

Yup. Time to get new rotors. May as well do pads at the same time, however, you could still get a couple months out of those.

Insane435 · 10-14-2018, 08:05 PM

Damn i guess ill have to get new rotors and pads. I am going to be storing the car in 30 days so it wont be driven that much more. Hopefully it will be ok for another month. Ill just monitor it each day.

cfm56d7b · 10-14-2018, 09:57 PM

How old are the existing rotors? It does look like the rotors need to be replaced.

Solidjake · 10-14-2018, 10:30 PM

Quote:

Originally Posted by Insane435

Damn i guess ill have to get new rotors and pads. I am going to be storing the car in 30 days so it wont be driven that much more. Hopefully it will be ok for another month. Ill just monitor it each day.

Order the rotors/pads from FCP since they have lifetime warranty. You can wear down the brakes again and they will replace it with new ones. Just pay shipping to send it to them and that's a lot cheap then buying everything new each time.

Insane435 · 10-14-2018, 10:36 PM

Quote:

Originally Posted by cfm56d7b

How old are the existing rotors? It does look like the rotors need to be replaced.

Installed last year. Probably have at most 20k miles on them.

N420i · 10-15-2018, 10:14 AM

Although a bit much, 20k miles for a set of very aggressively driven rotors in a high-powered, heavy car with some track time on them is not completely crazy... Specially depending on what pads you're running.

Are the grooves gone on both sides of the disc?
Are they gone on both discs?
What pads are you using?

perryo91 · 10-15-2018, 10:24 AM

Quote:

Originally Posted by Solidjake

Order the rotors/pads from FCP since they have lifetime warranty. You can wear down the brakes again and they will replace it with new ones. Just pay shipping to send it to them and that's a lot cheap then buying everything new each time.

Isnt it normal wear/tear... so they wouldnt cover it under warranty?

Billfitz · 10-15-2018, 10:38 AM

Quote:

Originally Posted by perryo91

Isnt it normal wear/tear... so they wouldnt cover it under warranty?

Go to the FCP site and you'll see. They tend to be higher priced than most sources, but where it's a part that you can expect to replace again it's worth it.

Insane435 · 10-15-2018, 10:41 AM

Quote:

Originally Posted by N420i

Although a bit much, 20k miles for a set of very aggressively driven rotors in a high-powered, heavy car with some track time on them is not completely crazy... Specially depending on what pads you're running.

Are the grooves gone on both sides of the disc?
Are they gone on both discs?
What pads are you using?

cant see the back, but they are not gone yet on the passenger side. Both front pads do look a pit low. I am running the PowerStop Track days. I think I am going to switch to the M Pads and call it a day.

Solidjake · 10-15-2018, 10:48 AM

Quote:

Originally Posted by perryo91

Isnt it normal wear/tear... so they wouldnt cover it under warranty?

I've seen a few pages on instagram with people who tracked and showed pics of the used rotors going to fcp and them taking it

Insane435 · 10-15-2018, 11:39 AM

Quote:

Originally Posted by Solidjake

I've seen a few pages on instagram with people who tracked and showed pics of the used rotors going to fcp and them taking it

FCP even states they cover wear and tear. It's part of their policy.

N420i · 10-16-2018, 11:04 AM

Quote:

Originally Posted by Insane435

cant see the back, but they are not gone yet on the passenger side. Both front pads do look a pit low. I am running the PowerStop Track days. I think I am going to switch to the M Pads and call it a day.

It's probably not the case since from what you're saying I interpret that although not identical the wear is more or less the same on both sides, but I was asking beacuse perhaps you have a seized or stiff piston in the driver's side...

I'm not familiar with the PowerStop pads, but aggressive pads will eat rotors. I have a couple of friends that are very fond of Carbonne Lorraines because of the stopping power and fade resistance but they are essentially changing discs very time they change pads. This is on a Renault Clio and a Nissan Pulsar so rotors are cheap. Not so much on an F3X...

Billfitz · 10-16-2018, 11:08 AM

The reason why stock BMW pads make so much dust is that they're softer, to extend rotor life. The dust is a PITA, but less so than premature rotor replacement.

enjoythemusic · 10-17-2018, 07:51 AM

Slits and dimples are really only needed when wet imho as it helps with wiping effect. Other than that, you're reducing the ability of the pad to make direct contact with the rotor's metal surface, thus reducing grip potential. Furthermore, those dots and slots add more wear to the pad.

Am i surprised at the high wear rate during track events? Absolutely not. That's normal. Yes, check rotor thickness and obviously you know the pads need to be replaced. That's all part of tracking as car. Normal stuff really.

Logicoeur · 10-17-2018, 10:00 AM

Quote:

Originally Posted by enjoythemusic

Slits and dimples are really only needed when wet imho as it helps with wiping effect. Other than that, you're reducing the ability of the pad to make direct contact with the rotor's metal surface, thus reducing grip potential. Furthermore, those dots and slots add more wear to the pad.

Am i surprised at the high wear rate during track events? Absolutely not. That's normal. Yes, check rotor thickness and obviously you know the pads need to be replaced. That's all part of tracking as car. Normal stuff really.

Yes they are for escaping moisture and dust allowing more uniform contact from the pads. The additional wear is minimal though.

I've had setups with cross drilled holes and it wasn't this bad, although I had hawk HPS ceramic pads.

I believe its his tracking, and braking habits on the street that are the culprit here. Brake earlier on the streets and, coast more.

IK6SPEED · 10-17-2018, 10:19 AM

Now glad I purchased my Brembo rotors with drilled holes instead of the above. Up to now I had pondered if I made a mistake.

FaRKle! · 10-17-2018, 10:56 AM

Quote:

Originally Posted by IK6SPEED

Now glad I purchased my Brembo rotors with drilled holes instead of the above. Up to now I had pondered if I made a mistake.

It's more of his braking than the actual rotors. I put 4 track days and 7mo/12k mi of driving on MSport rotors and didn't even wear them down 15% (I measured and compared to BMW specs before selling to a friend).

Insane435 · 10-17-2018, 11:01 AM

Quote:

Originally Posted by FaRKle!

It's more of his braking than the actual rotors. I put 4 track days and 7mo/12k mi of driving on MSport rotors and didn't even wear them down 15% (I measured and compared to BMW specs before selling to a friend).

It could be the pads. They are aggressive. Sparks literally fly when i brake. I am running the power stop track days. They are like anchors but the dust level is too much for daily. They can also be very loud. I may just run m pads and maybe power stops on track only.

Logicoeur · 10-17-2018, 08:59 PM

Quote:

Originally Posted by IK6SPEED

Now glad I purchased my Brembo rotors with drilled holes instead of the above. Up to now I had pondered if I made a mistake.

Well I wouldn't say all of that.

Its actually more difficult to tell if the rotors are worn past the min thickness since the drilled holes go ALL the way through the rotor.

With the dimples you will know, just with a glance, as to how much smaller the dimples have become, or in this case completely gone.

With the cross drilled rotors you have to physically run your fingers across the outer edge to see how deep the outer ridge has become. And then it's still kind of just a guestimate. Plus the cross drilling actually makes the rotors more prone to cracking (right from the drilled holes outward). Moreover there's less rotor material to dissipate heat.

BUT cross drilled rotors look much better IMO.

enjoythemusic · 10-18-2018, 05:22 AM

Quote:

Originally Posted by Logicoeur

I believe its his tracking, and braking habits on the street that are the culprit here. Brake earlier on the streets and, coast more.

But being King of the Late Brakers is soooooo much more fun. Just ask my wife

10-14-2018, 06:15 PM	#1
Insane435 Major 478 Rep 1,467 Posts Drives: 435ix M Sport EWG Join Date: Jul 2016 Location: Michigan iTrader: (1)	Slots and Dimples disappeared on M Perf rotor... How is this possible? Are they just that worn down? Also, my pads look like they have nothing left after 2 track days and 3 months of driving. Anyways, i did not think the slots and dimples could disappear. Can i still drive this thing or do i need to replace ASAP? You can see how it had the slots and dimples at one point. Grooves gone. Pad wear. __________________ 2014 EBII 435ix - Stage 2+ Dragy: 0-60 3.61; 60-130 10.18 2020 MG M340ix - Dragy: 0-60 3.48 2018 LBB X4M40i - Stock Dragy: 0-60 4.85
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10-14-2018, 07:00 PM	#2
Billfitz Lieutenant General 8245 Rep 16,088 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	I can almost guarantee that your rotors are less than minimum acceptable thickness.
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10-14-2018, 07:22 PM	#3
Logicoeur Lieutenant Colonel 993 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	Yup. Time to get new rotors. May as well do pads at the same time, however, you could still get a couple months out of those. __________________ F30 335iX \| Remus Axleback \| Fabspeed Catted DP \| VRSF Comp IC \| 18X9 ET35 19lb MT1 \| 255/40/18 ECS \| Ohlins RT Millway Street \| Millway Control Arm Bushings \| Turner Endlinks \| TMH 75mm 14x1.5 Studs \| BMW MPerf LSD \| XDelete \| Pipercross Filter \| MHD Stg2 93
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10-14-2018, 08:05 PM	#4
Insane435 Major 478 Rep 1,467 Posts Drives: 435ix M Sport EWG Join Date: Jul 2016 Location: Michigan iTrader: (1)	Damn i guess ill have to get new rotors and pads. I am going to be storing the car in 30 days so it wont be driven that much more. Hopefully it will be ok for another month. Ill just monitor it each day.
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10-14-2018, 09:57 PM	#5
cfm56d7b Lieutenant General 5886 Rep 10,256 Posts Drives: 2017 440i Gran Coupe & 2015 X5 Join Date: Nov 2012 Location: Orange County, CA iTrader: (2)	How old are the existing rotors? It does look like the rotors need to be replaced.
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10-15-2018, 10:14 AM	#8
N420i Private First Class 72 Rep 192 Posts Drives: 2016 420i lightly modded Join Date: Nov 2016 Location: Madrid iTrader: (0)	Although a bit much, 20k miles for a set of very aggressively driven rotors in a high-powered, heavy car with some track time on them is not completely crazy... Specially depending on what pads you're running. Are the grooves gone on both sides of the disc? Are they gone on both discs? What pads are you using?
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10-16-2018, 11:08 AM	#15
Billfitz Lieutenant General 8245 Rep 16,088 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	The reason why stock BMW pads make so much dust is that they're softer, to extend rotor life. The dust is a PITA, but less so than premature rotor replacement.
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10-17-2018, 07:51 AM	#16
enjoythemusic Captain 364 Rep 775 Posts Drives: 2014 BMW 435i Dinan Stage 4 Join Date: Feb 2017 Location: Florida iTrader: (0)	Slits and dimples are really only needed when wet imho as it helps with wiping effect. Other than that, you're reducing the ability of the pad to make direct contact with the rotor's metal surface, thus reducing grip potential. Furthermore, those dots and slots add more wear to the pad. Am i surprised at the high wear rate during track events? Absolutely not. That's normal. Yes, check rotor thickness and obviously you know the pads need to be replaced. That's all part of tracking as car. Normal stuff really. __________________ Enjoy the Drive, Steven 2014 435i M-Opt, M LSD, Dinan CAI/IC/BTurbo/Stage 4, ER TIC/CP, GFB DV+, Fabspeed HJS cat DP & Mich PS4S.
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10-17-2018, 10:19 AM	#18
IK6SPEED Banned 4490 Rep 10,473 Posts Drives: BMW M3 / AH3 Join Date: Jan 2013 Location: Cali iTrader: (23)	Now glad I purchased my Brembo rotors with drilled holes instead of the above. Up to now I had pondered if I made a mistake.
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