ZCP vs CSL Wheel and Performance

[Tbonem3]

Problem with redoing CSL is that most places can't get it right. Powdercoat never looks good, must be paint, but even then multi stage with real metallic.

[old///MFanatic]

True that is a factor. But a factor with anything being painted. Just make sure the place knows what it’s doing with the BMW color. There are several threads on the Internet with the correct color and two stage paint.
I’ve had wheels straightened and powder coated, great for hiding small curb imperfections but on real CSL wheels you even more don’t want the markings hidden.

[lastMleft]

Apex’s are nowhere near as strong as BBS’s.

Even there forged wheels?

[jet_dogg]

Forged wheels where?

All forging is not the same.

[Obioban]

Even there forged wheels?

Yes, even their forged wheels.

[T.J.]

I went from 19” csl reps to 18” BBS RS-GT, which are forged and use titanium hardware. I couldn’t believe the weight difference when I was switching them out. These are 8.5” ET38 and 9.5” ET22, so they fit nice without spacers. I wouldn’t mind few more millimeters offset, especially up front with the free camber mod tucking them a little extra.

Frankly, I was also expecting a big change in ride stiffness/comfort changing to 18s but it was not very dramatic, I guess due to the ps4s stiffness.

On the looks, sure the CSLs rule but the period correct, motorsports look of these has grown on me. Only problem is the clear coat on the brushed barrels is starting to peel so I need to decide between polishing or trying to restore the brushed look

[eXpensiveGears]

Wow, this thread blew up! Thanks again for all of the information guys, I appreciate it. It seems like either refinishing the ZCP's or even buying a new set (if available) might be the way to go considering the marginal weight savings against CSL's.

The 18" RS-GT's do look really nice though the weights still seem around 20-21lb mark.


I started this thread as well as the one about the CSL Seat as I'm slowly but surely looking to do a "full" build on my 06 SG ZCP. Now with the CA SMOG ECU issue, I don't think I'm going to be able to add any power mods and tune so figured I'd tackle the other side of the equation: Weight.

Plans are to change: Wheels (maybe), AP Racing/PFC/Brembo BBK, Manual Bucket Seats, CF Roof, CF CSL Trunk, Differ and possibly Front Bumper, CF CSL center console and doorcards possibly as well, Lithium Ion Battery. Take out the HK Sub and replace the rest of the speakers with Focals.

I'll send PM's and maybe start a separate thread when I get there, but those are the thoughts I have as of now.

[tnord]

I went from 19” csl reps to 18” BBS RS-GT, which are forged and use titanium hardware. I couldn’t believe the weight difference when I was switching them out. These are 8.5” ET38 and 9.5” ET22, so they fit nice without spacers. I wouldn’t mind few more millimeters offset, especially up front with the free camber mod tucking them a little extra.

Frankly, I was also expecting a big change in ride stiffness/comfort changing to 18s but it was not very dramatic, I guess due to the ps4s stiffness.

On the looks, sure the CSLs rule but the period correct, motorsports look of these has grown on me. Only problem is the clear coat on the brushed barrels is starting to peel so I need to decide between polishing or trying to restore the brushed look

I'm not very good at this, but I think 8.5'' +38 is the same fit regarding fender 'flushness' as my 9'' +31?
and my 10'' +25 would actually have a little more room than your 9.5'' +22?

The more I look into the BBS option, the more I don't like size options. The GT4s seem to need a hub ring so that's a no-go. These RS-GTs might get the offset right, and look the part, but I really like the fit of my 255/275 on 9'' and 10'' wheels.

[Tbonem3]

I'm not very good at this, but I think 8.5'' +38 is the same fit regarding fender 'flushness' as my 9'' +31?

Opposite. A 9et31 would be a half inch further out at the fender than an 8.5et38.

You'd put a 5-10mm spacer on an 8.5et38 wheel to get it to look similar to a 9" et31.

There's a 6.35mm or 1/4" difference at the fender between 8.5 and 9" wheels (or any 1/2" diff wheelset). BUT, you do have to take the tire into consideration. If it's the same tire, it'll be stretched a little more and clear a little easier on the wider wheel. Also, a wider wheel will come into the well more and possibly touch the springs, esp progressive springs (tho that's not an issue on 9" but 9.5 et22 and greater I believe)

[E46_M3_ZCP]

As a general formula, where:

D = Distance from hub mounting surface to rim outside edge -->This is the value you want to use for comparison sake
W = Wheel width in inches
O = Offset in mm, for example et+38 is a positive offset of 38mm

D = W divided by 2 minus O divided by 25.4, just be mindful of the units as wheel width is in inches and offset is in millimeters and 1" equals 25.4mm

As Tbonem3 stated, you had it opposite since 8.5 et31 calculates to D = W/2 - O/25.4 = 8.5/2 - 31/25.4 = 3.0" which is the same as 9.0 et38 which calculates to 9.0/2 - 38/25.4 = 3.0"

But calculated how you had originally stated it 8.5 et38 calculates to D = W/2 - O/25.4 = 8.5/2 - 38/25.4 = 2.75" which is different from 9.0 et31 which calculates to 9.0/2 - 31/25.4 = 3.25", and that's where the 1/2" further out number Tbonem3 stated above comes from

*5mm spacer equals 5/25.4 or 0.20" and a 10mm spacer equals 10/25.4 or 0.40"

[tnord]

I just went to BBS' website, and there are TWO wheel options for an E46 M3 in 18''. So everybody looking for these just has to scour the interwebs looking for a used set to refurbish?

Rays wheels you might wait 6-12mos to receive your order. BBS wheels essentially have zero options with the proper sizing. I don't know much about titan7, but since they don't advertise where the wheels are mfg, I'm guessing it's china.

Same with Bimmerworld TA16, and Apex forgings; made in china.

forgeline doesn't appear to have any options

HRE has been previously mentioned as not that good.

Work wheels has a couple options, but they list 5x120 as "optional," which likely means unavailable. But plop down a fistfull of $1000s up front, then hope they show up within a year?

I'm really struggling to find any options besides chinese forgings or scouring the used market unfortunately.

[jet_dogg]

Wow.

[Tbonem3]

Ya, like when you get to 30 years old and you realize the ads/movies/products aren't geared towards you any more.

You make do. Stay stock, go used or go chyna.

You could do what Mr. Wolfe did and have a shop widen some ZCPs and make the ultimate CSL wheelset like 9"et28 & 10"et20.

[tnord]

it's not like I'm wondering why you can't get 14'' watanabes anymore. From the reaction to my "just throw apex's on it" sentiment, I was expecting at least a few new, off the shelf options for a strong, light, properly fitting wheel. Albeit expensive. That doesn't seem to be the case.

[K-Dawg]

The wheels with the arguably best combination of "quality" and "fitment" for the E46 M3 were brought to market by RAC Monolites. Even in the heyday of this platform, they could only muster limited interest and this was reflected in the numbers of wheels built.

I recently saw mention that maybe they could be talked into another run... I might be interested in a set of staggered 18s.