Tech Question: Hair line Fractures on Front rotors

[pmajka]

Hair line Fractures on Front rotors due to over braking on the track. 

Pass:
Fail:
OMG replace them now!:

[Darren]

Can you take a picture?

[George3]

It's kind of normal for the rotors to developing the small cracking from the extreme heat generated.

I do not think they need replacing unless the cracks are connected,

Or, you feel a vibration under braking.

[michael lang]

You didn't indicate if they are cross-drilled and you didn't say what the measurement was. George has a good point about them in regards to vibration under braking. I wouldn't worry too much about the cracking unless there were a large number of cracks and they connected the holes if your brake rotors are cross-drilled or there was a vibration in brake pedal under braking which would indicate the rotors are under spec and are now warping. Good news is that unlike your windshield, brake rotors are real cheap.

 

[George3]

I carry an extra set of rotors in my trailer.  Had them since I noticed the cracking on my rotors back in March.  I've got a lot of events on them and they still look fine and the cracks have not connected.

[AMoore]

I believe, and I'm sure I will be be corrected if I'm wrong, but if you have cross drilled rotors, it is OK to have cracks unless more than two holes are connected by cracks, or unless the cracking goes to the edge of the rotor.

[George3]

+1   ^

[pmajka]

Slotted, not cross drilled...no pulsing under braking,


I just never saw that before.....

I think i will toss my spare Rotor in for Watkins Glen just in case.