Floating Rotors or 1 piece?

[Christopher72]

Front rotors need replaced -- starting to lip, etc. It's a fun driver and not a track car, so are the single piece rotors fine or the OEM 2 piece recommended?

 

[B21]

The OE are two piece to cope with heat causing different cracking..

They are not floating rotors which have lateral play ..

I wouldn’t on a 35i go with one piece…

 

[Christopher72]

https://www.bimmerworld.com/Front-2-piece-Floating-Brake-Rotor-OEM-E89-Z4-sDrive35is-E9X-335i.html
https://www.bimmerworld.com/Brakes/...9-Z4-all-except-35is-34116794427-Genuine.html

Looks like there's floating and non-floating 2-piece options.

 

[B21]

https://www.bimmerworld.com/Front-2-piece-Floating-Brake-Rotor-OEM-E89-Z4-sDrive35is-E9X-335i.html
https://www.bimmerworld.com/Brakes/...9-Z4-all-except-35is-34116794427-Genuine.html

Looks like there's floating and non-floating 2-piece options.

Brembo and I would call those 2 piece or composite discs..ie hub in aluminium..rotor in cast iron..held together rigidly together with rivets..

A floating rotor has two pieces but instead of a rivet holding the two parts together it has a bush where the rotor has significant lateral play or float ..

https://www.bremboparts.com/europe/en/products/prime/two-pieces-discs

Refers

 

[Christopher72]

Thanks for the education. The two options there did look very similar. Whereas a single Brembo that floats cost more than a full set of those rotors. If I had Brembo money, I'd just get a new M4

 

[B21]

Yes they did …OE BMW one for 35i one not..

Zimmerman offer nice OE quality versions in 2 piece with nice drill holes as an option..

I use them on the rear …I have a 6 pot Brembo upgrade on the front so use different two piece rotors..not floating ..

FWIW the floating ones tend to be very rattley anyway…

 

[spitfun]

I did not know the 35i came with 2 piece rotors,maybe only with upgraded front brakes? I swapped mine out already to coated one piece units,but the one I took off were I believe oem and were one piece.

 

[B21]

I did not know the 35i came with 2 piece rotors,maybe only with upgraded front brakes? I swapped mine out already to coated one piece units,but the one I took off were I believe oem and were one piece.
Screenshot_20230406_075437_Gallery.jpgScreenshot_20230406_075515_Gallery.jpg

On the 35is in all markets the OE fit was the 2 piece unit..

https://www.bimmerworld.com/Front-2-piece-Floating-Brake-Rotor-OEM-E89-Z4-sDrive35is-E9X-335i.html

 

[Christopher72]

Mine are shot and can't be original at my mileage. They are both lipped and unloved. The Zimmermans 2 piece coated seems like decent replacement.
Any recommendations on low dust pads? Anyone know how bad a set of 90k mile calipers will be? rebuild them for the sake of rebuilding them?

 

[B21]

Textar who are OE for BMW do ePads which are low(er) dust..I use them on the rear (front now 6 pot brembo) to good effect

https://www.fcpeuro.com/products/bmw-brake-pad-set-textar-epad-2331382#fitment

It wouldn't hurt to get a seal and sliding caliper seal kit for the calipers maybe new pins for the floating caliper part..