$42 Rotors on RockAuto?

[PYE46M3]

Originally Posted by GeorgeA

Leave it to a non-BMW guy to not noticed the difference between a semi-two piece OEM quality rotor and a single piece one where 10% of the rotor surface isn't aligned to the pad.

Simply buy Zimmerman or any respectable OE replacement if you don't want OEM.

Non BMW guy? lol okay !

Do you really think you will notice much of a difference between 2 piece OEM rotors and one piece rockauto rotors on the streets on a boat like the E9x M3? btw you said cheap not worse performing.

I've gone through 20 sets of various brand rotors from rockauto for multiple cars so far and never had any issues whatsoever. Would I buy them for any of my M cars? probably not. I got OEM rotors for my Z4M... because I didnt mind spending the money to have a 2 piece rotor. But that doesn't mean the rockauto ones are "cheap" and would kill me on the road. thousands and thousands of miles so far on cheap $25 centric, powerstop and beck/arnley rotors so far for my DD and zero issues.

[GeorgeA]

Originally Posted by PYE46M3

Non BMW guy? lol okay !

Do you really think you will notice much of a difference between 2 piece OEM rotors and one piece rockauto rotors on the streets on a boat like the E9x M3? btw you said cheap not worse performing.

I've gone through 20 sets of various brand rotors from rockauto for multiple cars so far and never had any issues whatsoever. Would I buy them for any of my M cars? probably not. I got OEM rotors for my Z4M... because I didnt mind spending the money to have a 2 piece rotor. But that doesn't mean the rockauto ones are "cheap" and would kill me on the road. thousands and thousands of miles so far on cheap $25 centric, powerstop and beck/arnley rotors so far for my DD and zero issues.

I’m talking about putting rotors like that on the M3 since this is an E92 M3 forum.

You absolutely will notice the difference, especially on a heavier car. Single piece cheap rotors heat up and warp.

If you drive an M3, you care about performance naturally and brakes aren’t a good place to save $$.

[GeorgeA]

Originally Posted by rbryantaz

Heh not sure where this back and forth came from.

It is possible for lots of companies to make a decent rotor. My point was just that rockauto had incorrect pictures and then was petty with their return process. If they had been alloy and low quality then I would have also evaluated that and stopped using them.

The "OEM only" idea gives some guarantee of quality but isn't always best. There are better pads than OEM and there are non OEM rotors that are just as good as OEM.. It just turned out that I got a lower end rotor when it was shown as a higher end alloy rotor... I posted to make sure that Boone else bought them and then had to return them.

You’re fine sticking to OE manufacturers like Zimmermann but one piece rotors are a downgrade and don’t belong on a car like this.

Genuine BMW rotors are better than any aftermarket for this application and I’m basing this off of harder use compared to aftermarket’s like Zimmerman. But Zimmermann is great for daily use.

Most of those budget brand rotors warp real quick and aren’t suited for these power and weight levels.