10-05-2003, 06:25 AM
|
 |
Account Under Review
Location: Fairfield, NJ
|
|
Join Date: Mar 2003
Posts: 921
Mein auto: 2001 540i 6-Speed
|
|
Quote:
|
Originally Posted by Malachi
Its my understanding that you don't reface or "turn" these rotor because they are mad of aluminum and not steel. So, no....
|
They aren't aluminum. They are iron. There is very little metallurgical difference between rotors from BMW, Mercedes, Brembo, Zimmerman, StopTech, etc. The manufacturers play around a little bit with impurities (e.g., phosphorus) to trade off characteristics such as hardness for susceptibility to pad deposition. But all mainstream rotors are made from what is called gray iron.
There have been repeated attempts to use aluminum alloys in rotors to reduce weight, the latest being something called metal matrix rotors by a company called CoolTech. But at high temperatures, even temperatures that could be experienced on the street, the coefficient of friction dropped dramatically, making them unsafe.
|