I just got home from a DE and I was removing my track rims and adjusting everything back to normal street use when I noticed that there are hairline cracks in my stoptechs...

These things are friggin expensive and I did not buy them for them to be cracking. Is there anything I need to be worried about at the moment?!? :help They are barely noticeable unless you get really close (as if you were changing out the brake pads).

Also, this would probably be ridiculous asking stoptech, but do you think perchance I could get a new set of rotors from them?

Thanks guys...

call them up and see

I just got home from a DE and I was removing my track rims and adjusting everything back to normal street use when I noticed that there are hairline cracks in my stoptechs...

These things are friggin expensive and I did not buy them for them to be cracking. Is there anything I need to be worried about at the moment?!? :help They are barely noticeable unless you get really close (as if you were changing out the brake pads).

Also, this would probably be ridiculous asking stoptech, but do you think perchance I could get a new set of rotors from them?

Thanks guys...

I can't help you with your question, but out of curiosity, are they drilled, slotted, or plain rotors? Just curious... I've noted somepeople saying that cross drilled rotors are prone to cracking under heavy track use.


-David

I can't help you with your question, but out of curiosity, are they drilled, slotted, or plain rotors? Just curious... I've noted somepeople saying that cross drilled rotors are prone to cracking under heavy track use.


-David
Cross drilled, I'm trying to get my sig to work so you can see them there.

I've never had a problem with cross drilled, on my track car (the Z3) I ran them till they were grooved out and had to replace the rotors, not because of cracking, (zimmerman rotors) and that car saw hard track use. I don't get it.

This is normal wear. Have the same thing on mine. These are just at the surface. Just remember to keep an eye on them, like any rotor. Next time you might want to go with slotted rotors as I am told they are more effective for track use.

its normal but still call stoptech to see if they will give you free rotors :D :D :D

Yea I heard before that in the E36 M if you use cross drilled for track use youll crack them everytime.

Yea I heard before that in the E36 M if you use cross drilled for track use youll crack them everytime.

Holes are pretty, but slotted is the way to go on the track!

Holes are pretty, but slotted is the way to go on the track!
Yes but unfortunately only big name BBK kits come with cross drilled :(

Yes but unfortunately only big name BBK kits come with cross drilled :(

Not true! UUC offers slotted rotors and I've seen that Stoptech offers slotted rotors as well.

Unless your rotors are for show , go with slotted!

Yes but unfortunately only big name BBK kits come with cross drilled :(

Stoptech and Brembo definitely come with slotted rotors as an option. If you really track the car, then slotted are the way to go. Drilled will eat through your pads and will eventually crack from the holes.

They are still fine, Stoptech will tell you this. You just need to keep an eye on the cracks and make sure they don't turn into something worse. There is a miminum thickness that Stoptech will spec. Just measure and you'll tell.

When you need to replace the rotors, just get the slotted the next time around.

Not true! UUC offers slotted rotors and I've seen that Stoptech offers slotted rotors as well.

Unless your rotors are for show , go with slotted!

Actually the Stoptechs come "standard" with the slotted rotors. The drilled rotors are a $100 option.

These cracks are a biproduct of the disc casting process. When the disc cools after casting, the outside of the disc cools faster than the inside, causing variations in hardness. Therefore, the outside of the disc is slightly more porous than the material underneath. When the disc face heats up under track conditions it tends to shrink the iron on the face slightly causing those small hairline cracks....sometimes called hazing.

It is perfectly normal and safe. You just need to make sure there are no cracks reaching the disc edge or the mounting holes. Hope this helps.

Stoptech are pretty good with their warranty. Give them a call. It's worth a try, other wise it will cost you ~$500 for a pair of new rotors. Try getting slotted instead of x-drilled to avoid this problem again.

Yes but unfortunately only big name BBK kits come with cross drilled :(

You dont think Stoptech is a big name? Besides brembo, what do you consider big name?

I think brands like Brembo, AP and even domestic brand like Baer and Wilwood are significant larger than Stoptech.

You dont think Stoptech is a big name? Besides brembo, what do you consider big name?

Try getting slotted instead of x-drilled to avoid this problem again.

Slotted, plain faced....all discs will do what he is describing if they get hot enough. I'll try to see if I've got some discs at the office tomorrow to show y'all what he's talking about. They are not the same as the cracks you get with x-drilled. They're not really cracks at all.

This isn't a warranty issue even! Any rotor will do this under its first hard track use. Initial hairline cracks will grow slowly and then stop. Then lots more use. Then the cracks will suddenly start growing again. When you can stick your fingernail in the rotor, you need to think about replacement. You will be paying for new rotors because even the might Stoptech hasn;t figured out a way to make rotors so they have no wear!!!

From his description this is what he is seeing (not as bad as some I've seen):
http://img.photobucket.com/albums/v127/rj3series/disc2.jpg

these have worn down some, but are still visible:
http://img.photobucket.com/albums/v127/rj3series/disc1.jpg

This isn't a warranty issue even! Any rotor will do this under its first hard track use. Initial hairline cracks will grow slowly and then stop. Then lots more use. Then the cracks will suddenly start growing again. When you can stick your fingernail in the rotor, you need to think about replacement. You will be paying for new rotors because even the might Stoptech hasn;t figured out a way to make rotors so they have no wear!!!

HAHAHA...James beat me to it. This thread is hilarious :stickoutt

When you can stick your fingernail in the rotor, you need to think about replacement.

Just make sure and wait for them to cool first! :stickoutt

Thanks James. Wasn't totally sure whether this was a joke....

Dan Law