sprbxr

Which rotors are better?

Justin

IceShark

A much debated topic. The "cross drilled" rotors usually run cooler like on the order of over 100 o F than slotted rotors so are "better". The cross drilling lets the hot gas from the pads escape faster. There are numerous other issues that you can read up on if you search the net.

The major drawback of cross drilling is cracks forming from the holes due to heat cycling. Slotted can crack too, though not as prone as drilled. This cracking of drilled can be largely overcome if you get the Porsche rotors that have the holes cast into the rotor rather than mechanically drilled. Those are the ones you want to get. And I understand the factory culls out the best rotors and sends those to Porsche. So, all rotors are not equal and it is a good idea to go with the Porsche ones.

TurboGuy

I have a set of the forged cross drilled rotor set. They are manufactured in Germany by Zimmerman. Zimmerman is the OE for Porsche rotors. They are made of a very high iron content to resist warping as well. I purchased my set from german parts and restoration but be careful they will rust immediatley. Before installation take a can of high temp BBQ gloss black paint and spray all the non friction surfaces in and out. If you get them wet dry the rotors right away to prevent rust from forming and to prevent rust drips on your wheels. In hard braking conditions these rotors will run over 100 F cooler than the standard rotors ! Good luck.

Jerry

Yes they must be the forged type but at twice the price they must last twice as long to break even but theweight savings is nice. It might be 8 lbs. each.

Chazmo

I burned through a front set of the Porsche 968 M030 crossdrilled rotors in about 7 drivers ed schools. I am an instructor, so we get full use of the track ourselves on Friday's so it's not unusual to clock 200 track miles in one day. Those crossdrilled rotors(Porsche) were also cryro treated and purchased from Diversified cryrogenics. The cracks that develop from the extremely high heat conditions put them at a disadvantage to my experience with the slotted cryro treated Porsche rotors. Thermal heat stickers on the calipers did not indicate any difference in high teperature reached. The crossdrilled rotors are more than double the price and I could not tell the difference in performance. I do have the 968 M030 brake duct cooling package on my car. The cross drilled rotors look cool, but since I treat rotors like brake pads (carry an extra set), the slotted perform equal to the cross drilled and don't warrant the extra money spent. This is only my opinion. You may experience different results. Hope this helps.

belz

Chazmo ... couldn't agree with you more!
However, for me the jury is still out on Cryo ... I'm not sure I see any difference in rotor life. Definately no difference in braking performance. I'm not convinced it's worth it. I think the key is buy good quality rotors period.