Which rotors to choose from?

[m3f_Sirius_880bd69485]

My front rotors are warped, nice! I really like the look of cross-drilled rotors though.



What do you recommend for front rotors? I pland on using oem pads with them, cause I can get them real cheap at work, and they work just fine for my normal driving.



Ideas?

[m3f_DSK M3/4_7bd32f4682]

just get the euro floaters. cross-drilled and slotted look cool, but don't work as well as the euros.

[m3f_M3AN_5f4dc0ba80]

Since I've been looking for the same thing I can summarise my findings:



In terms of stopping performance, compound aside:



Plan one-piece rotors have relatively poor performance

Grooved/drilled one-piece rotors are the next in line



It's a toss up in performance as far as I can tell between a plain floating rotor and a two-piece grooved/drilled rotor (with alu hat). If somebody could confirm this it would be nice to know.



Contrary to popular opinion drilled rotors are not necessarily significantly weaker or prone to breaking. If you get a quality drilled rotor it will be fine but offer little or no street benefit over grooved. My common finding was the only drilled rotors from the top 3 or 4 manufacturers are worth considering (Brembo and AP Racing are the two I consistantly see getting named).



Over here a Euro floater costs the same (~) as an EBC grooved, "drilled" (one-piece) rotor. Based on the above logic a Euro rotor would be my best choice (I'm considering a BBK now though).



For you, I would check out the price of a Euro floating rotor, if it's cost effective get that. If not, consider a one-piece replacement for your OEM that is grooved (and/or drilled if it's reputable).



Also see: http://216.118.109.8/m3forum/showthread.php?t=26967

[m3f_Sirius_880bd69485]

Okay. I have had several people mention Brembo and Zimmerman to me. Ill research the floating rotor (clueless as to what this is right now) option, see what I can come up with. Thanks for the input as always

[m3f_Sirius_880bd69485]

Another thing though, I saw looked around and saw this, supposedly this is for the m3, wasn't specfic as to which series.. but are these what you are talking about when it comes to the floating roters? Still not clear on what a floating rotor is. Ill ask my parts guy tomorrow when I go in to work....



http://home.att.net/~stl_don/euro_rotors.htm



Thanks again

[m3f_M3AN_5f4dc0ba80]

Okay,



Those pics are of rotors from a Euro E46 M3, they're floating.



A floating rotor can be of (at least) two designs, I'll try and explain.



Let's start with a common rotor though. A common (one-piece) rotor is cast from one piece of steel (or other suitable compound) so the enire thing is one piece of metal.



A two-piece rotor is made of two primary pieces. There's the actual disk, which is the biting surface that the pads clamp on. Then there's the hub or hat, this is the piece the bolts onto the car at the centre of the rotor assembly. In many cases this is a different colour to the disk and you can see the bolts whereby the two pieces are attached. These have many advantages, cooling being one and the fact that the disc can be replaced without needing to replace the hat is another.



A floating rotor is basically a two-piece rotor with some margin for movement between the hat and the disk. This can be acheived in a number of ways. One way is to have a small space for movement around the bolts (see above) and the other, as implemented on BMW and Audi's is to use dog gears or sliding bolts (as shown in the pics on the site you've linked).



In the pics you can see how the hat/hub has a gap between itself and the actual disk. In the close-up you can see the lugs or bolts between the two pieces that are holding them together. These are evenly spaced around the entire assembly. These bolts and fixed at only one end (the hat end I think).



The advantage of this setup is that the disk can change shape (under temp) independantly of the hat which improves alignment with the pads when they clamp. Also cooling is improved by a) the gap b) the thermal conductivity of the alu and bolt setup.



Any of the above setups can have a plain, grooved and/or drilled surface.



I've learnt a lot in the last few days about brakes. The above is based on what I understand to be accurate. If I'm wrong, I'd be happy for somebody to correct me.



:thumbsup:

[m3f_DSK M3/4_7bd32f4682]

as you probably know, the euro version of the E36 M3 differed from the NA version. it had the better engine, the 6 speed (3.2L only), better headlights, and slightly better brakes. the engine and transmission are difficult to swap over, but the headlights are easy. the only component (that i know of) that separates the euro M3 brakes from the NA M3 brakes is the front brake rotor. the euro version is a "floating" design, where the braking surface and the hub are two separate pieces bolted together, whereas the NA version is a solid piece. the euro version does a better job of dissipating heat.

[m3f_DSK M3/4_7bd32f4682]

well, i guess i know what happens when i take a couple of phone calls while writing a reply...

[m3f_Sirius_880bd69485]

Intresting. I really like the looks of the euro rotors, not to mention all the good I am hearing about them. I guess its time to research prices and such :P



As always, thanks again