Cross-drilled rotor question

[Jim]

I heard that the cross drilled rotors have a reputation of exploding under extreme conditions (this is in general, not necessarily DBA's fine products) and that CAMS has banned the use of them in motorsport.

Can you clarify this for me? I'd like to know once and for all.

Cheers!

[dbasteve]

Originally posted by Secoh
I heard that the cross drilled rotors have a reputation of exploding under extreme conditions (this is in general, not necessarily DBA's fine products) and that CAMS has banned the use of them in motorsport.

Can you clarify this for me? I'd like to know once and for all.

Cheers!

Cross Drilled rotors are a great STREET product, but under excessive track conditions the lesser material mass generates more heat and the holes become stress raisers. This accelerates fatigue and these rotors crack.
Slotted rotors are the standard issue for track use as the slots effectively clean the pads and the rotors still have the maximum strength to deal with the temperatures for a longer period of time.

Any disc rotor used on the track will fatigue much quicker than one used for street. Generally the result is a cracked disc before they wear out.
The idea is to replace them before they crack.
When a disc is fatigued you will see very small cracks on the braking surface. When the cracks are more than 1/3 the pad width long or more than 0.25mm deep, its time to change them.

http://www.dba.com.au/forum/crazing_b.jpg

[Jim]

fantastic, thanks! this is exactly the kind of info we need.

cheers!