Dot pattern on rotor - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

86league · 03-21-2022, 04:00 PM

What would create a pattern of dots like this on a rotor? Is this ABS?

Off a friends car - rotors were replaced due to development of moderate shudder. Centric premium rotors for the Brembo (PP) brakes, XP10 pads - using enduro 200 TW tires (SX2, RS4).

Trying to figure out what caused it and prevent future shudder.

Thanks!

EndlessAzure · 03-21-2022, 04:12 PM

Looks like pad overheated and deposited material on the surface. The pattern seems indicative of ABS like you mentioned.

Does your friend use a lot of ABS in their driving style?

rice_classic · 03-21-2022, 09:34 PM

Ditch Carbotech and never look back. What you have there is an uneven transfer layer, an unfortunate characteristic of carbotech pads and yours looks like it was induced by ABS, possibly while the transfer layer was initially being laid down.

Rotors fine though. I solve this by putting a really harsh/aggressive pad and dragging the brake a bit while everything is cold and it cleans it off. But you could just buy new pads and rotors as well.

86league · 03-21-2022, 10:31 PM

Quote:

Originally Posted by EndlessAzure

Looks like pad overheated and deposited material on the surface. The pattern seems indicative of ABS like you mentioned.

Does your friend use a lot of ABS in their driving style?

Not sure how much ABS - I think everyone in my group of track friends are trying to limit ABS but I'm sure none of us can say we completely avoid it.

gcmak · 03-29-2022, 11:41 PM

Can't tell the thickness of the rotor and/or if there's a lip but that's just pad deposits/smearing from slightly overheated pad materials. This can be scrubbed off with some aggressive brake pad bedding / re-bedding, turning/resurfacing of the rotor, some work with a scotch brite pad, etc.

As long as the rotors are still within spec on thickness and not truly warped, they're totally good.

As others have kind of stated, you've found a thermal limit to part of your brake setup. You can keep your setup and adapt as a driver, or start changing parts. A combo of both is likely the best outcome.

CSG Mike · 03-30-2022, 07:21 PM

Looks like overheated pad.

get a higher spec pad.

03-21-2022, 04:00 PM	#1
86league Senior Member Join Date: Jul 2016 Drives: '13 BRZ Limited Location: League City, TX Posts: 202 Thanks: 16 Thanked 114 Times in 66 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Dot pattern on rotor What would create a pattern of dots like this on a rotor? Is this ABS? Off a friends car - rotors were replaced due to development of moderate shudder. Centric premium rotors for the Brembo (PP) brakes, XP10 pads - using enduro 200 TW tires (SX2, RS4). Trying to figure out what caused it and prevent future shudder. Thanks!

03-21-2022, 09:34 PM	#3
rice_classic Senior Member Join Date: Jun 2012 Drives: Nevermorange FRS Location: Seattle, WA Posts: 4,171 Thanks: 757 Thanked 4,206 Times in 1,807 Posts Mentioned: 78 Post(s) Tagged: 1 Thread(s)	Ditch Carbotech and never look back. What you have there is an uneven transfer layer, an unfortunate characteristic of carbotech pads and yours looks like it was induced by ABS, possibly while the transfer layer was initially being laid down. Rotors fine though. I solve this by putting a really harsh/aggressive pad and dragging the brake a bit while everything is cold and it cleans it off. But you could just buy new pads and rotors as well. __________________ SCCA T4 - FRS Last edited by rice_classic; 03-21-2022 at 10:41 PM.

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03-29-2022, 11:41 PM	#5
gcmak Member Join Date: Jun 2020 Drives: GR86 Location: California Posts: 86 Thanks: 220 Thanked 88 Times in 44 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Can't tell the thickness of the rotor and/or if there's a lip but that's just pad deposits/smearing from slightly overheated pad materials. This can be scrubbed off with some aggressive brake pad bedding / re-bedding, turning/resurfacing of the rotor, some work with a scotch brite pad, etc. As long as the rotors are still within spec on thickness and not truly warped, they're totally good. As others have kind of stated, you've found a thermal limit to part of your brake setup. You can keep your setup and adapt as a driver, or start changing parts. A combo of both is likely the best outcome.

03-30-2022, 07:21 PM	#6
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,562 Thanks: 8,942 Thanked 14,211 Times in 6,854 Posts Mentioned: 970 Post(s) Tagged: 14 Thread(s)	Looks like overheated pad. get a higher spec pad.

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