Porsche Brembo 996 BBK conversion

[Nate047]

Stuck with the ZCPs that I already had and added spacers. I want 18s but the car doesn’t see a lot of street miles anyway since I normally just drive the M5 or my wife’s Mazda, and drive to the track on my TA16s.

They look good and haven’t been destroyed (yet) by our cracked and pothole covered roads.

What width and offset are your TA16s, and do you use a spacer with them?

[repoman89]

Stuck with the ZCPs that I already had and added spacers. I want 18s but the car doesn’t see a lot of street miles anyway since I normally just drive the M5 or my wife’s Mazda, and drive to the track on my TA16s.

They look good and haven’t been destroyed (yet) by our cracked and pothole covered roads.

[Sprp85]

Yeah, an 8.5 ET22 is already about right for street width and offset IMO, I personally wouldn’t want to push that out further. A less aggressive offset with a spacer would work. It would annoy me to spend all that money on wheels and have them not fit properly though so I haven’t done it. RGRs have increased in price quite a bit in the last couple years too.

Thanks again for the input! I guess its either get a new set of wheels or stick with the stock brakes... Which wheels, for street duty, did you go with?

[repoman89]

Thanks for chiming in Tbone, Obioban & Repoman;

So in short, the E46-spec RG-R can clear 996 BBK with spacers, and as offset on RG-Rs is determined by the barrel position, a rather conservative offset is actually beneficial in this case.

And since the E39-spec RG-R is already sitting pretty far out at 8.5 width + ET22 and it will be difficult to slap on a decent-sized spacer on them, thus it won't work for 996 BBK. Yea?

Yeah, an 8.5 ET22 is already about right for street width and offset IMO, I personally wouldn’t want to push that out further. A less aggressive offset with a spacer would work. It would annoy me to spend all that money on wheels and have them not fit properly though so I haven’t done it. RGRs have increased in price quite a bit in the last couple years too.

[Sprp85]

Thanks for chiming in Tbone, Obioban & Repoman;

So in short, the E46-spec RG-R can clear 996 BBK with spacers, and as offset on RG-Rs is determined by the barrel position, a rather conservative offset is actually beneficial in this case.

And since the E39-spec RG-R is already sitting pretty far out at 8.5 width + ET22 and it will be difficult to slap on a decent-sized spacer on them, thus it won't work for 996 BBK. Yea?

[repoman89]

I’ve got ST40s under 18” RG-Rs on my e39 M5, with no issue…

I’m talking about a test fit of the E39 spec front RGR on the front of an E46 M3 with 996 front brakes. That fitment isn’t close. The M5 front hub must have the brakes mounted further inward — I know people only need small and sometimes no spacer to run Brembo GT kits on that chassis as well.

[Obioban]

I’ve got ST40s under 18” RG-Rs on my e39 M5, with no issue…

[repoman89]

Just guessing, I'd say 8.5"et22 WOULD fit without a spacer, but have a 3mm-5mm on hand just in case?

It doesn’t and it’s not even close with RGRs. On that particular wheel the hub mounting area and spokes are all basically the same shape and the different offsets are created by just shifting the barrel and where it mounts to the spokes in and out. As the above poster read somewhere, I did try it with my set that I bought for my M5. I would have bought another set if they fit for sure, the design is perfection IMO.

The only non-rep 18” wheel that I personally like and have found so far that will fit properly without spacers are a custom set of LMs for $10k. Maybe someday but I’m using my ZCPs for now with 18/12mm spacers.

[Tbonem3]

It'll depend partly on the design of the wheel (spokes) not just width/offset. Every wheel is different. I thought for sure I'd be ok with the 9"et30 Arc-8s, but still needed 5mm minimum to clear. My 8.5et29 E90 M3 wheels fit perfectly, however, but I noticed that the spokes on those are quite scalloped or curving out (convex), so it cleared the big 996. The ARC8 spokes are straight, thus they strike the calipers at an offset below et25 it seems.

Just guessing, I'd say 8.5"et22 WOULD fit without a spacer, but have a 3mm-5mm on hand just in case?

[Sprp85]

Any thoughts on 996 BBK clearance with E39-spec'd BBS RG-Rs? I have a set of 996 calipers being prepped but was looking to plan ahead in terms of fitment with the current wheel setup.

• 18x8.5 ET22 Front
• 18x10 ET25 Rear

The general consensus seems to be that it won't clear, and I believe Repoman has already test fitted them and found that it won't clear,

But I was also able to find someone who did get them to work with E46-spec RG-Rs (18x8.5 ET38 Fronts) with a 12mm spacer up front (guessing based on the owner's previous posts):

A 12 mm spacer would effectively make the front specs 18x8.5 ET26.


Thread about the wheels shown above: 18" BBS R-GR's w/Porsche 996 BBK Fitment - NA M3 Forums

[Tbonem3]

Oe is ate I believe. I saw it stamped on the rotors when I installed them with my 996 conversion.

Technically speaking, since Zimmermann supplies parts to BMW (and probably other German brands), they'd be considered OEM. Aftermarket would be a part made by a company that doesn't supply any parts to major brand/factory. OE of course is the actual brand/part that our came with. Ate is oe for the solid discs and calipers and I'm pretty sure the euro semi floating discs as well.

[heinzboehmer]

I always thought that Zimmermann were the OE ZCP rotors.

Same, but FCP labels Zimmermann as aftermarket, so not sure what to make of that.

For what it's worth Zimmermann and VNE are also labeled as aftermarket for the non-ZCP euro rotors. Makes me think they're all the same, just rebranded.

But anyway, SHW is the cheaper than Zimmermann and labeled OE, so I'll likely stick with those.

[duracellttu]

I always thought that Zimmermann were the OE ZCP rotors.

[heinzboehmer]

Yeah that makes sense. I'll shop around, but I'll be using these on track, so the SHW rotors from FCP are tempting.

[Tbonem3]

I think it's like "VNE" and other companies that resell OE parts. ABelectrik makes our TPS, but "VNE" buys them wholesale and resells them. You buy the VNE part on FCPeuro, but you receive an ABE part with the BMW logo ground off (or never imprinted).

These "SHW" rotors are still BMW (ATE?) rotors.

I was about to buy these SHW rotors (for E90 M3), but I ended up getting the same price buying OE bmw from a bmw dealership (husker - bmwdirectparts.com). Might want to cross-shop by part #, but I wouldn't hesitate to buy the SHW from FCP if there is a price difference.

Coincidentally, I received an email from Eeuroparts.com advertising 5% off SHW brake parts (June20-24), so that might be worth looking into - though I don't know what their starting price point is, relative to FCP or any other source.