[Volasko]

I'm doing a 335i brake retrofit for my 330i mainly because it was cheap and easy and gives me MUCH more track pad options. Anyways I was entertaining going with an aluminum hat rotor for the fact the aluminum doesn't rust and offers some rotating weight reduction (the 335i rotors are LARGE). Theoretically it would have less thermal capacity vs. a standard steel rotor set and I thought that on the track this may actually be a detriment even though the lighter rotating mass would help (JUST a little). Am I over thinking this? Price not withstanding would you still choose a solid steel rotor for tracking vs the two piece aluminum hat rotor?

Thoughts?

[6ixSpd]

Many performance cars use aluminum hats on their rotors. There is no detriment to your application.

[feuer]

It will be better in thermal capacity because the aluminum disperse the heat better so wheel bearing won't be over heating. Yes, is lighter, about 1lbs but won't make much difference because the weight lost is in the center of the rotational mass. Then lastly, cosmetics, it will look better for longer.

[roastbeef]

thermal capacity is a term often thrown around when talking about brakes. capacity is irrelevant. you don't want capacity, or to hold heat- you want to get rid of heat.
two piece rotors are better suited for shedding heat. aluminum hat, two piece rotors are superior to solid rotors. solid rotors are also more prone to cracking since they can't expand as they naturally would want to.
if you can, choose slotted rotors over drilled rotors.

i just shopped rotors for my wife's 335d, but just ended up with oem- she's never going to put the brakes to heavy use. i did take a liking to the stoptech slotted rotors though. that would have been my choice.

[Volasko]

Price was just too damn much for the Aluminum rotors (about $600 CAD) so I ended up with simple high carbon centric blanks.