todinlaw

I know this topic has been discussed several time. I understand the recomendation that the rotor should be changed once the micro cracks either connect to 3 holes or a stress crack goes to the outside of the rotor. I also found some discussion that if the crack reach 7mm that they should be changed. Has anyone gone beyond what you see hear on my front rotors?

CWay27

I would use them Still for a few more days.

sweanders

How thin are they?

C.J. Ichiban

order new ones, drive them til the new ones arrive! lol.

just pretend like you're driving a double stint at lemans or something and be realllllllllllly gentle

sweanders

The cracks don't look bad, and the holes close to the edge have none. But in the pic it looks like they lip is deep. Could be a visual thing..

mjb

Those are fine. Rule of thumb is rotors need to be replaced if cracks are connecting holes or reaching the edge of the rotor. Of course also if you reach the wear limit, so buy a micrometer and test the rotor thickness from time to time. My cup rotors start cracking after the second track day.
Also, probably a good idea to clean the brake dust out of the drilled holes.

Have some new slotted rotors to try next and we'll see if those last longer.

todinlaw

Its not a good picture as I had washed the car and it has some surface rust. there is no lip, it is a visual thing. I have the spare rotors sitting on the bench so I could even bring to track if I had to. I am sure no one has driven rotors to failure but would you expect some vibration or any kind of warning. I agree that other than the fact that the cracks are getting long, no holes are connected an most cracks are in the middle nothing close to the outside. Just put some Yellow 29's on and would want to break the new pads in on the old rotors first.

My replacements are Protosport slotted.

sweanders

Once they fail there is no warning, a chunk of the rotor lets go and it is not pretty. Worst cases are very little brake performance or a locked wheel..

mjb

Don't know what "warning" overly worn rotors would give since I've never let them get that far without replacement. How many track days do you have on those? If there is no lip then they are probably wihin wear tolerance and the cracks are not bad so you are probably OK.

todinlaw

I have 20 track days but consider the first 10 I was leaning the car and track so the last 10 have been much harder I have just replace the first set of pads they were OEM. When I have looked at other guys rotors there cracks looked to be smaller and closer together, mine are long and straight. Not that it makes a difference but the cracks are not wandering to another hole they are just going up and down. Trust me, not planning on driving to failure, just looking for some reassurance I am not missing anything since this is my first go around with this part of the hardware replacement.

rmag

Thickness still looks ok by looking at the wear indicator "dimples"

C.J. Ichiban

there's a bit of a lip on the edge if you look at the left side of the photo...

time for cup car rotors!!!!!!

Sharptt

Don't shortchange the first 10 days. Early in the learning curve is frequently harder on the brakes since most drivers brake with less force for longer distances and scrub off more speed than necessary. Going faster usually means less time on the brakes, more time on the gas and higher speeds ie cooler brakes. These still look OK as others have mentioned.

Carnerd

Wow, you got 20 days??? I've got 5 on mine and they look like that.

mooty

if yours looked like that, after two LS days, you need new rotors i guarantee that.

LS is 3x harder on brakes than TH.