[razzle45]

So my front rotors are at 34.3. Minimum spec is 34.4. I just got iSweep pasd and plan on reusing the rotors as I just got them maybe 20k miles ago. Should I turn the rotors or just do a standard 50-10 bedding process?

[sec_mk3]

You should replace the rotors. Below spec

[razzle45]

Originally Posted by sec_mk3

You should replace the rotors. Below spec

The interesting part is BMW didn't recommend to replace them. They recommended 1 hr labor to tighten a loose screw on the rear electronic parking brake but didn't take the opportunity to gouge me for the rotors. To give you perspective they also recommended a coolant change for $300.

The other interesting thing is I personally measured them and got 34.6 and 34.7 on the two fronts and 23.9 and 23.4 on the rears. I believe minimum spec is 34.4 for the front and 22.4 for the rears. I'm thinking I surface all of them and throw on iSweep pads on both the front and rears.

[Bc2005]

BMW does not recommend resurfacing rotors. If they are in spec, just use them. If they are too worn, replace them.

[razzle45]

Originally Posted by Bc2005

BMW does not recommend resurfacing rotors. If they are in spec, just use them. If they are too worn, replace them.

Of course they don't recommend turning rotors, they want to sell you a new one. So you recommend just replacing the pads and leaving the rotors alone? Wouldn't it be better if I turned them to prevent any harsh vibrations or noise in the future?

[razzle45]

I drive the car pretty aggressive on the street and sometimes light tracking. Would you guys say its better to go with slotted or oem rotors? The cost is +$300 for slotted so not too much of a difference.

I understand slotted rotors go through pads quicker and that's my concern. Has anyone had any experience with slotted rotors?

[2Slow2Content]

My $0.02: For aggressive street use, you won’t notice a difference. Back when I used to go to the track, i tried both and never noticed a difference.

[sec_mk3]

Originally Posted by Bc2005

BMW does not recommend resurfacing rotors. If they are in spec, just use them. If they are too worn, replace them.

I am not sure this is accurate. Procut - on car brake lathe is certified by BMW for use on their cars. Procut makes adapters to support the largest M brakes.

I would never just replace pads unless I knew the rotors were within specs and had no runout. I am saying this for a daily driven car - track car, different story.

[sec_mk3]

Originally Posted by razzle45

Of course they don't recommend turning rotors, they want to sell you a new one. So you recommend just replacing the pads and leaving the rotors alone? Wouldn't it be better if I turned them to prevent any harsh vibrations or noise in the future?

Yes, it would be better if you turned them using an on car brake lathe - matches the rotor to the hub.