Drilled Rotors Susceptible to Cracking?

[JeepFlyer]

I was told that Wilwood's slotted & drilled rotors (as opposed to just slotted) were susceptible to cracking near the drill holes due to the heating and cooling cycles. Has anyone heard this before? I figured it would probably be more of a possibility with any drilled rotors, but is it really so bad that they should be avoided altogether? If there are rumors or stories about it, is it just Wilwood? I'm not planning to be doing any heavy track or autocross driving, so should I be concerned?

[GT-Tom]

My understanding is yes, drilled rotors tend to crack near the holes over time. Track days tend to cause them sooner because of the heat cycles. They generally are not recommended for street drivng because the average driver does not inspect his rotors on a regular basis. Racers inspect their rotors before and after each race. That being said , you can't deny the really cool bling factor of drilled rotors. :cool: I was told to go with slotted rotors for track days as they would hold up better for occasional track and autocross. If I was just doing a street car I would go for the drilled rotors but would inspect my rotors on a consistent basis for safety. This is not Wilwood specific.

Tom.

[CHOTIS BILL]

Yes drilled rotors will diffidently start cracking at the holes but using a bell shaped counter sink to debur the hole on both sides and having the rotors cryogenically treated will extend their life a lot.

Bill Lomenick

[FFRSpec72]

Dimpled rotors work better than the cross drilled ones, so a dimpled slotted rotor will serve you fine.

[tdhallum]

This is a common topic on almost any internet car forum. There are always people quick to say that cracking is common, but when pressed, I have never been able to find anyone to actually admit having experiencing it. I've had drilled rotors on several cars, including one that was used heavily for autocross and my current one, a 4300 lb. Hemi Dodge Magnum with 14 inch Brembos that I've used for everything from towing to the occasional track day with no issues. I won't say that it can't happen, but I don't think it is a common as people say. I would just recommend going with a trusted brand of rotors and not the ebay deals....

[CHOTIS BILL]

I have had many drilled disk crack on my DSR's and the larger the holes the quicker they cracked.

Bill Lomenick

[Zaphod]

This may be apples to oranges, but my 2000 Kawasaki ZX-12R has its original stainless drilled front rotors, with many many track days, hard street riding, 45,000 miles and not a crack in sight.

[crash]

I have cracked them...but I drive race cars.

I will not put drilled rotors on anything that has a relatively long service life. Any endurance race car will NOT get drilled rotors. They do seem to help slightly with cooling, but the surface area is also decreased by the holes, so the only times I have used them is in extremely tight track configurations where the brakes were being used constantly. I would say, due to cost considerations and braking surface area, not neccessarily cracking issues, 95% of the time I have used slotted rotors as opposed to drilled rotors for race car use. Like someone else said, they look cool, and on the street that's pretty much what it is all about so you will be fine with or without the drilled rotors. Really comes down to your personal preferrences...and if you want to have conversations like this regularly. If you get the drilled rotors, it is likely some people will tell you that they aren't the best choice. If you get "regular" rotors...well I've never heard a conversation that went "don't you know what you're doing? You need drilled rotors". ;)

[Wayne Presley]

I have cracked them...but I drive race cars.

I will not put drilled rotors on anything that has a relatively long service life. Any endurance race car will NOT get drilled rotors. They do seem to help slightly with cooling, but the surface area is also decreased by the holes, so the only times I have used them is in extremely tight track configurations where the brakes were being used constantly. I would say, due to cost considerations and braking surface area, not neccessarily cracking issues, 95% of the time I have used slotted rotors as opposed to drilled rotors for race car use. Like someone else said, they look cool, and on the street that's pretty much what it is all about so you will be fine with or without the drilled rotors. Really comes down to your personal preferrences...and if you want to have conversations like this regularly. If you get the drilled rotors, it is likely some people will tell you that they aren't the best choice. If you get "regular" rotors...well I've never heard a conversation that went "don't you know what you're doing? You need drilled rotors". ;)

X2 on everything said. I have 3 sets of cracked drilled rotors for the Elises we race, all been replaced with slotted rotors.

[Wayne Presley]

And the slotted rotors are not immune to cracking either...

http://i213.photobucket.com/albums/cc175/vcpinjectionpb/20120709_173632.jpg

http://i213.photobucket.com/albums/cc175/vcpinjectionpb/20120709_173621.jpg

[FFRSpec72]

And the slotted rotors are not immune to cracking either...


You can leave it at "no rotor is immune to cracking either" as I have had both solid and vented rotors crack.