if cross drilled brake discs are so bad, why do almost all manufacturers use them for their brake packages?

for example, porsche, bmw, lamborghini, mercedes, aston martin, etc all have cross drilled brake discs

only aston martin has slotted brake discs on some of its cars




aren't cross drilled brake discs more prone to cracking than slotted ones?
or does it even matter if they are high quality brake discs?

also does it matter if carbon ceramic brakes are cross drilled? do they crack?

 

Its pretty much just a style thing nowadays. Just flashy looking.

 

Cross drilled discs made by Porsche aren't the same as cross drilled discs for $50 a pop at you local speed shop. Also, most of those high end cars never see the track and if we are talking about race cars, the discs live for 1 race.

 

Most of the cars also use either carboceramic discs or plain\slotted metal one when they are actually raced.

http://photos.motoiq.com/MotoIQ/Feat...38_YJmAZ-L.jpg

http://cache.gawker.com/assets/image...esta09-112.jpg

http://www.speedhunters.com/wp-conte...859_1zJe_2.jpg

http://blog.mercedes-benz-passion.co...2C1041_100.jpg

 

corvette stopped using them for 2014 due to breakage and went to the slotted type.

 

Guy I know had a number of hot street cars, and raced a Panoz Esperante. I asked him one day why all the street cars had drilled and slotted rotors, and the Panoz was slotted only. He took me to a bench where he had drilled rotors off the Panoz sitting around, and every single hole had heat stress cracks spidering out in every direction. His point was that for street use, drilled is ok, but the heat of track use didn't get along with the drilled units. And since at least some of the point of drilling is supposed to be heat dissipation, it sort of makes them for appearance only., IMO.

 

They are not bad,

Just get some of these to go with them.

Cross Drilled Brake Lines - $72.95 : KaleCoAuto.com, Your home for the rare, unusual, and hard to find auto parts.

 

Perfect addition would be the mother of all subs: Mother of all Subwoofers - $8,260,000.25 : KaleCoAuto.com, Your home for the rare, unusual, and hard to find auto parts. ... a mere 8.2 million dollars

 

ill take 2

 

I like slots, but then I like to track.

 

I have recently bought EBC slotted and dimpled disks. Here is the rear one:

 

I'd be curious to know if the cross drilled rotors that are having stress cracks around the holes merely have holes drilled through them or if the edge of each hole is carefully chamfered. Even if they are, they won't be chamfered on the inside in the vents. This will be the source of cracking. Anywhere there is an edge, there is higher stress. It's even the main reason airliners have rounded corner windows.

 

i'm pretty sure the holes are supposed to be cast in

 

No, they are drilled into the rotor, a decent rotor will have the holes radius chamfered.

 

mostly for looks.
however higher brand cars probably use better material but doesnt mean they also dont crack. the problem is most rich people dont service their cars their own so they just bring it in.
BMW suggest changing the rotors with the pads everytime where others just true the rotors and put on new pads and call it good.
it all boils down to affordability. I dont think any $100k-$200k car owners will mind some $1000-$2000 rotor replacement.

 

also, which one (cross drilled or slotted) wears down the brake pads more?

 

Cheese grater?

 

My two piece rotors don't show stress cracks around the holes... They show stress cracks around the entire rotor.

Everything has a positive and negative effect on a car, sometimes the negatives outweigh the positives.

 

For a decent (pseudo) cross drilled rotor for track or street - you need only think outside the box, or, in this case, inside the slot...

Disc Surface Finish - RacingBrake.com

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