[AtlasM]

Just for kicks I was looking at RockAuto for Z4 35is front rotors. They list a Bendix PRT6356 which is specific to the Z4 35is for $34.79 each. The only problem is there are no notes on if they're actually 2-piece rotors, and no pictures. The catalog on the Bendix website lists 2 different Z4 rotors, PRT6366 for the 28i & 35i, and PRT6356 for the 35is, but same deal, no details on if they're 2-piece.





But you'd think that maybe since they're specific to the 35is, they could be 2 piece?

I also looked up some other application guides, specifically Centric, which is the parent company of StopTech. They list a part # 125.34132 for the Z4 35is front rotors and the pictures on their site seem to indicate 2-piece rotors, and they say "Mounting Type: Floating" but I can't find this part number for sale anywhere.



Anyway, I sent an email to Bendix customer service to see if the PRT6356 is a 2-piece rotor. Because hey, 70 bucks for a pair of Z4 35is rotors is a steal.

[Volasko]

In for more information. Doubt it is 2 piece, pricing wouldn't make sense. Especially if it is indeed aluminum.

[feuer]

The listed weight is 22.48 and Z4 are 22.8 so is possible that they are 2-pcs with aluminum hat. Cast iron OEM weights 23.8 and most aftermarket are even heavier at 24.2

[AtlasM]

That 22.48 listed weight is on the Centric part that is likely the 2-piece design but not available anywhere that I could find.

I called RockAuto about the Bendix part but they didn't have any additional information other than "it's listed by the manufacturer as fitting that vehicle."

I'm tempted to take a flyer and buy them just to find out, but my rotors are fine and I'd like to get slotted ones when it's time to replace them. Also I've got enough other car car crap piled up in my garage that I'm sure to irritate my wife if I add another box of it haha.

[andrey_gta]

Keep in mind these would work with 335i calipers, not the 330i calipers.

[AtlasM]

Well yeah, the Z4 35is rotors are the same 348x30 mm size as the 335 rotors and since I have a 335 that's why I'm posting about these.

It appears that Z4 28i/35i could be an upgrade for 330i and other cars with 330x24 mm rotors. I don't know for sure if they fit but they are both the same size, and again the Z4 rotors are 2-piece. RealOEM lists the 330i etc. rotors as 9.06 kg vs. 8.48 kg for the 330i etc. rotors. That's apparently a 1.28 lb difference.

The Z4 330x24 mm rotors I've found are Bendix PRT6366 for $26.79 each (same deal as the Bendix Z4 35is rotors, don't know if they're 2-piece), DuraGo BR901054 for $61.79, and Centric 125.34120 for $73.79. The DuraGo and Centric both do appear to be 2-piece.

DuraGo, the description on RockAuto says "2-Piece Design; Features Riveted Aluminum Hat; Vented" and these are the pics:



RockAuto doesn't list details on Centric but this is from the Centric site, it has a similar rounded hat as the other 2-piece rotors:



Compared to Centric 125.34079 which is their 330i application, it's just a line drawing but appears to be a 1-piece rotor:

[feuer]

DuraGo is 2-pcs. Pronto and Pilenga too. Centric aren't. They only have rounded hat like the Zimmermans.
http://www.partsgeek.com/gbproducts/...ad=47433964212
http://www.partsgeek.com/mwkwnlc-bmw...ake-rotor.html
http://www.partsgeek.com/8smkmf6-bmw...ake-rotor.html

[Volasko]

Super tempted to take a shot at these. I can't stand how much my "geomet" coated rotters from ECS tuning have rusted.

[AtlasM]

Originally Posted by feuer

DuraGo is 2-pcs. Pronto and Pilenga too. Centric aren't. They only have rounded hat like the Zimmermans.
http://www.partsgeek.com/gbproducts/...ad=47433964212
http://www.partsgeek.com/mwkwnlc-bmw...ake-rotor.html
http://www.partsgeek.com/8smkmf6-bmw...ake-rotor.html

Interesting. It was hard to tell from the small pictures of the Centric but it looks like the Centric 125.34132 348x30 mm rotor is a 2-piece with the rivets or whatever they are along the side of the hat. The Centric 125.34120 330x24 mm, it's hard to pick out from the picture but I believe you're correct they are 1-piece with rounded hat like Zimmerman. Kind of a moot point since I can't find the 125.34132 348x30 mm for sale anywhere.

Originally Posted by Volasko

Super tempted to take a shot at these. I can't stand how much my "geomet" coated roated from ECS tuning have rusted.

Any coated rotor, the coating eventually wears away from the face of the rotor where the pad touches it. Or are you talking about the hats rusting?

Since you have a 330i looks like you have DuraGo BR901054, Pronto 30422-05264501 and Pilenga W0133-1935021 to choose from among the 330x24 mm Z4 2-piece rotors.

[feuer]

Originally Posted by AtlasM

Interesting. It was hard to tell from the small pictures of the Centric but it looks like the Centric 125.34132 348x30 mm rotor is a 2-piece with the rivets or whatever they are along the side of the hat. The Centric 125.34120 330x24 mm, it's hard to pick out from the picture but I believe you're correct they are 1-piece with rounded hat like Zimmerman. Kind of a moot point since I can't find the 125.34132 348x30 mm for sale anywhere.

That number pulls regular 1-pcs rotor. Crappy if you ask me.
http://www.autoanything.com/brakes/77A7561A4483870.aspx

Originally Posted by AtlasM

Any coated rotor, the coating eventually wears away from the face of the rotor where the pad touches it. Or are you talking about the hats rusting?
.

I have done it with great results on rotors that weren't coated to start with.

[AtlasM]

Originally Posted by feuer

That number pulls regular 1-pcs rotor. Crappy if you ask me.
http://www.autoanything.com/brakes/77A7561A4483870.aspx

I was going more off the images provided by Centric on their website, although they do say "REFERENCE ONLY".



If you look at the pic in the middle it appears to have the rivets on the side of the hat like the Durago 330x24 mm one (and the OE Z4).

But...still doesn't matter since they're not available anyway.

[weehe126]

I need to replace my front rotors soon and was just planning on going zimmerman. If we can get an educated guess on which might be the 2 piece I'll buy them to see.

[feuer]

Originally Posted by weehe126

I need to replace my front rotors soon and was just planning on going zimmerman. If we can get an educated guess on which might be the 2 piece I'll buy them to see.

See links in post#7

[weehe126]

Originally Posted by feuer

See links in post#7

I've never heard of Pronto. It clearly states 2-piece, but I wonder the quality. Pretty good price at $87 though.

[andrey_gta]

I am going to agree with others - these Bendix would be just cast 1 pieace rotors unlike the Durago brand.

[feuer]

Originally Posted by weehe126

I've never heard of Pronto. It clearly states 2-piece, but I wonder the quality. Pretty good price at $87 though.

If you had worked at repair shop the brand would have been familiar. I usually buy their brake cleaner. Is the cheapest around.

[weehe126]

Originally Posted by feuer

If you had worked at repair shop the brand would have been familiar. I usually buy their brake cleaner. Is the cheapest around.

I can't tell if that means they are actually good/decent. Repair shop can mean anything from Midas to high end indy.

[Volasko]

Originally Posted by AtlasM

Any coated rotor, the coating eventually wears away from the face of the rotor where the pad touches it. Or are you talking about the hats rusting?

Obviously I'm not talking about the rotor face, how much of a noob do you think I am!

See this picture of how they looked after one winter season:

https://drive.google.com/file/d/0B8p...ew?usp=sharing

The hat wasn't too bad in this picture as it was basically sealed from the anti seize I put on the hub ring to prevent wheels from fusing to them. Everything else is a rusted mess though.

[feuer]

Originally Posted by weehe126

I can't tell if that means they are actually good/decent. Repair shop can mean anything from Midas to high end indy.

The difference from Midas to high end shop is primarily in the vehicles being repaired. Now that doesn't mean high end car can't have a brake job done at Midas and vise versa. However having in mind that most vehicles on the road aren't high end I can tell you that they probably had a brake job done at the local Mida with one of these aftermarket rotors because who wants to pay top dollar to repair brakes on a commuter car? Do you see brakes failing often? No! Only issue with aftermarket is rust. These have alumunum hat so not an issue with rust. Be weary of aftermarket pads. Rotors will do just fine.

[AtlasM]

Originally Posted by Volasko

Obviously I'm not talking about the rotor face, how much of a noob do you think I am!

See this picture of how they looked after one winter season:

https://drive.google.com/file/d/0B8p...ew?usp=sharing

The hat wasn't too bad in this picture as it was basically sealed from the anti seize I put on the hub ring to prevent wheels from fusing to them. Everything else is a rusted mess though.

Well hey, you didn't say which part of the rotor was rusting so I asked. Didn't mean to imply I thought you were a noob.

I'm in Wisconsin so I have the same issues with winter. Even with anti-sieze, when I swap off my winter wheels I usually have to give at least one wheel a good whack with a rubber mallet to break it loose.

[AtlasM]

Originally Posted by weehe126

I've never heard of Pronto. It clearly states 2-piece, but I wonder the quality. Pretty good price at $87 though.

Moot point for you since the Pronto & Pilenga linked above are 330x24 mm for Z4 28i/35i. 335i needs a 348x30 mm rotor like Z4 35is.

I tried to look up with Pronto if they have a Z4 35is rotor but their catalog is like a master catalog of a bunch of other brands. But hey, more possibilities to research!

[AtlasM]

I called Bendix yesterday. The guy I spoke to said he didn't think they were 2-piece because he didn't know of any 2-piece rotors in their lineup. He said he would look into it for more detail and call me back but so far hasn't called back.