Do I have Comp/floating rotors?

[Ajcanadian]

Hi guys, I've got a 2002 E46 M3 and from what appears to be I might have competition rotors or the euro floating rotors on the fronts and back. I'm not sure which one they are. Is there any specific way to tell them what they are?

Photo of my car for reference

[Inizes]

You can measure the fronts. 345mm (~13.5 inches) in diameter is competition spec, 325mm (12.8 inches) would be non-zcp. Rears are the same diameter for both zcp and non zcp models.

[liam821]

You can also see between the actual rotor and hub, here is a picture:

[Inizes]

You can also see between the actual rotor and hub, here is a picture:

Shows a broke link on my end for your photo.

[liam821]

This better? Inizes

[Arith2]

I see both pictures fine. Look for them to be two piece and drilled. Comp rotors are drilled while regular are not. Also look between the rotor and the hub. You'll see where it is a two piece in the photo. There are little points all around connecting the two. Normal, stock one is just a solid piece of steel. There is no space to see through because the hub is also part of the same steel which ZCP is aluminum I think.

[Inizes]

I see both pictures fine. Look for them to be two piece and drilled. Comp rotors are drilled while regular are not. Also look between the rotor and the hub. You'll see where it is a two piece in the photo. There are little points all around connecting the two. Normal, stock one is just a solid piece of steel. There is no space to see through because the hub is also part of the same steel which ZCP is aluminum I think.

The drilled/non-drilled is true for OEM rotors but not for aftermarket providers like StopTech, ECS, and some others which is why I suggested measuring.

[Inizes]

This better? Inizes

First photo is broken on Tapatalk, works on Safari Mobile. I didn’t check on desktop. Second photo works on both.

[duracellttu]

Just take off the wheel, look for the part number, then look up the specs. It will be easy to determine if it’s a genuine BMW ZCP rotor.

[Ajcanadian]

Thanks everyone, for the input. I have confirmed that I have the floating rotors upfront. Same with the rears.

[Obioban]

Just because they're floating doesn't mean they're the comp pack rotors-- all the euro cars came with floating rotors front and rear.

[liam821]

Just because they're floating doesn't mean they're the comp pack rotors-- all the euro cars came with floating rotors front and rear.

tl;dr; you should really just measure them to be absolutely sure.