hairline fracturing in front brake rotor - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

JoeC · 09-29-2017, 10:42 AM

I went to swap in my track pads (Winmax W5) last night to get ready for a track day this weekend and found my front rotors looking like this:

https://imgur.com/tTypskf

(I'm getting an error trying to attach the image... "Upload failed due to failure writing temporary file.")

hundreds of tiny hairline fractures.

I don't have a lot of track car maintenance experience but in all my normal vehicle maintenance experience, I'd never seen anything like it. I'm guessing it's from rapid heat expansion and cooling? Both sides of both front rotors look like that. Is it bad? It looks to me like it's about to come apart in a million tiny pieces, hahha.

Slammillionaire · 09-29-2017, 10:48 AM

Picture isn't working, but if i saw cracks in the rotor on my car i would NOT drive it and I would have it replaced immediately. Don't want to have them fail while you're driving and end up killing yourself or someone else.

EDIT: I guess picture link was added. Doesn't look bad

Sapphireho · 09-29-2017, 10:55 AM

Sounds like time for new rotors.

Now that I can see the pic, your fine.

venturaII · 09-29-2017, 10:57 AM

https://ebcbrakes.com/articles/surfa...n-brake-discs/

JoeC · 09-29-2017, 11:16 AM

Quote:

Originally Posted by venturaII

https://ebcbrakes.com/articles/surfa...n-brake-discs/

I don't think that's it. take a look at the picture I linked.

JazzleSAURUS · 09-29-2017, 11:16 AM

Replace your rotors. Centric blanks are my preference for 95% of applications on these cars.

Code Monkey · 09-29-2017, 11:20 AM

That's normal, nothing to worry about.

8RZ · 09-29-2017, 11:24 AM

It's just surface crazing and will wear down smoothly over time and use.

JoeC · 09-29-2017, 11:25 AM

Quote:

Originally Posted by JazzleSAURUS

Replace your rotors. Centric blanks are my preference for 95% of applications on these cars.

Like these?
http://www.autoanything.com/brakes/6...RoCcB8QAvD_BwE

Tcoat · 09-29-2017, 11:32 AM

Quote:

Originally Posted by venturaII

https://ebcbrakes.com/articles/surfa...n-brake-discs/

This ^
As it says your pads are not removing the heat efficiently leaving the scary looking but totally harmless marks.
At work (we make rotors) we get attempted warranty claims for this all the time. It is a total non issue.

venturaII · 09-29-2017, 11:32 AM

Quote:

Originally Posted by JoeC

I don't think that's it. take a look at the picture I linked.

I did. And it is. I'd run them. But there's no accounting for not feeling confident in your gear, so if that's the case, replace them. But you're likely going to get the same results.

JazzleSAURUS · 09-29-2017, 12:27 PM

Are these stock rotors? How many miles? How many track days?

strat61caster · 09-29-2017, 12:42 PM

Thickness is more important than how the surface looks when it comes to deciding whether or not to replace them. Measure your rotors.

If you think you have cracks drag a fingernail across them, if your fingernail catches you have cause for concern, but if it's just a bit bumpy it's fine.

These things are stout as fuck, 63k DD miles and 5x track days on my OE rotors.

FirstWinter · 09-29-2017, 12:44 PM

It's heat checking. It's normal from track use due to the high temps your stock rotors see. I would replace when one of the cracks reach the edge or is large enough to catch a fingernail. Another way to test is to check the minimum thickness of your rotors. I would carry spare rotors on you.

09-29-2017, 10:42 AM	#1
JoeC Senior Member Join Date: Apr 2014 Drives: Subaru BRZ Limited Location: Colorado Posts: 354 Thanks: 477 Thanked 222 Times in 118 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	hairline fracturing in front brake rotor I went to swap in my track pads (Winmax W5) last night to get ready for a track day this weekend and found my front rotors looking like this: https://imgur.com/tTypskf (I'm getting an error trying to attach the image... "Upload failed due to failure writing temporary file.") hundreds of tiny hairline fractures. I don't have a lot of track car maintenance experience but in all my normal vehicle maintenance experience, I'd never seen anything like it. I'm guessing it's from rapid heat expansion and cooling? Both sides of both front rotors look like that. Is it bad? It looks to me like it's about to come apart in a million tiny pieces, hahha. Last edited by JoeC; 09-29-2017 at 11:03 AM. Reason: fixed the image (sort of...)

09-29-2017, 10:48 AM	#2
Slammillionaire Senior Member Join Date: Jan 2017 Drives: 2013 Hot Lava FRS Location: New Jersey Posts: 518 Thanks: 183 Thanked 527 Times in 259 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Picture isn't working, but if i saw cracks in the rotor on my car i would NOT drive it and I would have it replaced immediately. Don't want to have them fail while you're driving and end up killing yourself or someone else. EDIT: I guess picture link was added. Doesn't look bad Last edited by Slammillionaire; 09-29-2017 at 12:31 PM.

09-29-2017, 10:55 AM	#3
Sapphireho ¯\_(ツ)_/¯ Join Date: Mar 2016 Drives: '15 ultramarine Location: Idaho Posts: 13,195 Thanks: 5,451 Thanked 18,243 Times in 8,611 Posts Mentioned: 155 Post(s) Tagged: 0 Thread(s)	Sounds like time for new rotors. Now that I can see the pic, your fine. Last edited by Sapphireho; 09-29-2017 at 11:31 AM.

09-29-2017, 10:57 AM	#4
venturaII Only users lose drugs. Join Date: Nov 2014 Drives: All the time Location: Shrewsbury upon Worcestershire Posts: 1,819 Thanks: 874 Thanked 1,067 Times in 674 Posts Mentioned: 3 Post(s) Tagged: 2 Thread(s)	https://ebcbrakes.com/articles/surfa...n-brake-discs/ __________________ "To know a thing well, know it's limits. Only when pushed beyond its tolerances will true nature be seen." Amtal Rule

09-29-2017, 11:16 AM	#6
JazzleSAURUS Senior Member Join Date: May 2015 Drives: 15 BRZ LTD, 05 FXT Location: Western MA Posts: 1,032 Thanks: 561 Thanked 558 Times in 351 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	Replace your rotors. Centric blanks are my preference for 95% of applications on these cars. __________________ SOLD: 2015 WRB BRZ Limited ('02 WRX BBS, S-04's, Stoptech Sport pads, MXP SP, AVO drop in filter, Mishimoto Intake tube, decatted header, OFT 93 Stage 2 EL Tune, Kartboy rear shifter bushing, Whiteline transmission and subframe lockout bushings, ST Coilovers, SPC Camber bolts w/smaller crash bolt, SPC LCA's & SPC Toe Arm bushings, Red TOMs, TRD Wing.)

09-29-2017, 11:20 AM	#7
Code Monkey Senior Member Join Date: Jul 2016 Drives: Subaru BRZ Location: Atlanta, GA Posts: 838 Thanks: 869 Thanked 562 Times in 337 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	That's normal, nothing to worry about.

09-29-2017, 12:27 PM	#12
JazzleSAURUS Senior Member Join Date: May 2015 Drives: 15 BRZ LTD, 05 FXT Location: Western MA Posts: 1,032 Thanks: 561 Thanked 558 Times in 351 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	Are these stock rotors? How many miles? How many track days? __________________ SOLD: 2015 WRB BRZ Limited ('02 WRX BBS, S-04's, Stoptech Sport pads, MXP SP, AVO drop in filter, Mishimoto Intake tube, decatted header, OFT 93 Stage 2 EL Tune, Kartboy rear shifter bushing, Whiteline transmission and subframe lockout bushings, ST Coilovers, SPC Camber bolts w/smaller crash bolt, SPC LCA's & SPC Toe Arm bushings, Red TOMs, TRD Wing.)

09-29-2017, 12:44 PM	#14
FirstWinter Senior Member Join Date: Nov 2015 Drives: Car Location: Location Posts: 646 Thanks: 374 Thanked 422 Times in 254 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	It's heat checking. It's normal from track use due to the high temps your stock rotors see. I would replace when one of the cracks reach the edge or is large enough to catch a fingernail. Another way to test is to check the minimum thickness of your rotors. I would carry spare rotors on you.

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