[rak299]

This post results from my being bored while waiting for my car to SLOWLY cross the Atlantic then make its way through the Panama Canal to California. It gives me time to worry about things that probably don't matter to me. I am getting a 340ix with the M Sport Brakes (part of ZTR package). I can see from all the pictures that my brakes will have the larger 370mm disks, but they are not the slotted and drilled disks on the M3. I assume that the disks I am getting are 1-piece cast iron, rather than 2-piece cast iron/aluminium. Is that true?

Just for information, on the 2-piece disks, I never found the friction ring for sale separately. Am I looking at the wrong place or calling it by the wrong name, or is it just sold that way? It would seem that the hub would be unlikely to wear out.

I am sure that since I am not taking the car to a track and I mostly drive like an old fart anyway, the basic brakes would have fine, but I wanted the adaptive suspension and variable steering and the brakes came as part of the same package.

Thanks

[FaRKle!]

Your rotors (front and rear) are two-piece. The hat is aluminum and the ring is iron. It's a plain ring (no slots/dimples/drilled holes, the base M3 rotor only has drilled holes). The hat and ring are riveted together (you can't separate them and replace just the ring).

[rak299]

That makes sense. Thanks

[oceanview]

You actually get the M-Performance Brake rotors (in size and material) but without dimples/slots.

You could change to the M-Performance rotors keeping your pads and calipers.

But braking power will be about the same, so not worth changing for that reason.

[cfm56d7b]

Originally Posted by oceanview

You actually get the M-Performance Brake rotors (in size and material) but without dimples/slots.

You could change to the M-Performance rotors keeping your pads and calipers.

But braking power will be about the same, so not worth changing for that reason.

+1 It would not make sense to consider M Performance OEM brakes sold as an aftermarket accessory by BMW. The only meaningful upgrade would be a BBK (aka big brake kit) with 6 piston (front) and 4 piston (rear) calipers from Brembo or AP Racing. It's an expensive upgrade, about $3K-$3.5 per axle.