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      12-30-2012, 12:41 AM   #1
Space Admiral
splitsecond's Avatar

Drives: 135i
Join Date: Sep 2012
Location: St. Louis

iTrader: (1)

Garage List
2008 BMW 135i  [0.00]
Benefit of lightweight front rotors?

I know that the conventional wisdom is that decreasing unsprung mass will have a substantial impact on overall performance. But how useful is it to save 3 lbs from the front axle with lightweight rotors?

I did a google search, and some of the Evo guys have found measurable increases in awhp by losing 3 lbs from each brake rotor... but I wonder if we might get a similar effect by replacing front rotors on a RWD car.

And while I'm on the topic, I've seen a lot of different numbers for the BMW Performance rotors. Some places say that they're 21 lbs (which would mean a 1-1.5 lb loss), and some places say that they're 3-4 lbs lighter than stock. Does anybody know what the right answer is?
2008 135i Montego Blue sport pkg, premium pkg, Logic 7 sound, iDrive/Nav
Mods completed: JB4+ & FBO || LSD || BMW-P suspension + F/R sway bars || 18" Breyton GTS-R || M3 front bushings || Vogtland camber plates || BMW-P rotors + Stoptech pads |||| Acquired, not installed: BMS WW Meth kit || Logic HVI intake || Mishimoto OCC |||| Shopping for: Summer tires