BBS RC/ APEX ARC8 style CF wheels

[RazorM]

Hi guys,

i am in close touch with R&D team from hypersport car manufacturer and they are currently in process of developing/testing own CF wheels.
Since there is will to also merge that knowledge and technology for external project I was more than interested.

There is idea to take the most widely used design and spec of one wheel and make it from CF and make it somewhat affordable.

BBS RC or apex arc8 style wheel for example(maybe end up with something different. Only one width and offset to begin with so it’s simple and cost effective.
So my idea was to also take this task here to the eyes of community first to get some other perspectives.

Early calculations showed that 9,5j ET35 wheel would weight about 4,5- 5kg compared to 8,5kg apex states, while exceeding load rating.

Opened to the opinions if there is market for such a niche product and if those attributes would be worth the effort.

Cost calculations are in the works, but it would be considerable more budget friendly compared to what’s on the market available now.

[usdmej]

if it can only be one size you would probably get the most success with 18x9.5 +22

5kg target weight would be exceptional!

[RazorM]

if it can only be one size you would probably get the most success with 18x9.5 +22

5kg target weight would be exceptional!

Is not ET22 kind of hard to fit without big camber?
The offset was exactly the thing we were wondering. I think we are not even locked to offsets that are already existing, we can do 25 or 30 or whatever is best.
Or just cop/paste the ones that are used by other manufacturers

I believe we can be half the alloy weight, we will see after we determine the specs

[Tbonem3]

Is not ET22 kind of hard to fit without big camber?
The offset was exactly the thing we were wondering. I think we are not even locked to offsets that are already existing, we can do 25 or 30 or whatever is best.
Or just cop/paste the ones that are used by other manufacturers

I believe we can be half the alloy weight, we will see after we determine the specs

I think someone who modifies their M3 with wheels like these would have quality suspension and camber plates etc

That said, et25 is good because it fits better, and still clears BBKs and suspension. I'm having to use a 5mm spacer on 9.5"et35, so I way say 9.5"et25-28mm would be perfect for E46.

[Cronenberged]

Meet in the middle et28

[EthanolTurbo]

ET22 or ET25 would be great.

[Bry5on]

You guys are all crazy, et35 will give you better scrub radius, steering feel and control around the limit of the tire. You can get to et25 from et35, but not the other way around. I’d imagine that if someone is gonna shell out for this level of benefit, they’d be interested in maximizing engineering benefits. Maybe I’m wrong, but I’d love to see these exist on the market and be the most functionally engineered as possible! Good luck OP, send it.

[usdmej]

i'll come back and say that maybe the offset should be as high as possible without requiring spacers to clear a bbk in the front

18x9.5 +28 is a great happy medium imo

[usdmej]

You guys are all crazy, et35 will give you better scrub radius

just get wide fenders for your wagon and join the party

[Bry5on]

i'll come back and say that maybe the offset should be as high as possible without requiring spacers to clear a bbk in the front

18x9.5 +28 is a great happy medium imo

I run 17x9 et46 (et52+6mm spacer) Apex ARC-8s and I clear the 996 BBK, but there's no concavity on my wheels. For what it's worth.

just get wide fenders for your wagon and join the party

Honestly this is the sort of thing that would tempt me to go over the edge. I'd ideally go for the highest offset I could get with a 9.5 up front - ideally an et38-40. Seems like that'd be the ultimate killer compromise size with a 255 or 265.

edit: I will say that the ARC-8 spoke design doesn't seem to lend itself super well to a carbon wheel, as it wouldn't be the simplest layup and you don't get the benefit of hollow spokes. Might be worth considering a design that's more carbon friendly.

[cornerbalanced]

Is not ET22 kind of hard to fit without big camber?
The offset was exactly the thing we were wondering. I think we are not even locked to offsets that are already existing, we can do 25 or 30 or whatever is best.
Or just cop/paste the ones that are used by other manufacturers

I believe we can be half the alloy weight, we will see after we determine the specs

Seconding the notion that anyone going through the great expense to purchase carbon fiber wheels for their 20+ year old BMW will have camber plates and coil overs already, and likely a more aggressive alignment.

Would 18x10+25 be an option? This would also make the wheels accessible to the E9x M3 community (a large if not larger market for something like this), while remaining easily accessible to the E46 M3 community.

[RazorM]

Cross platform compatibility/usability would be definitely a plus. So wheel spec should be viable also on newer platforms as well, but also e46, since I will be testing and running those on my street car.

From my experience, I don’t even clear ST40 calipers with ET30 ARC8 without spacer, but I don’t take it for as much of a reference.

i agree that ARC8 is not the best design for CF, but it’s doable and it looks good. Or Maybe also SM10 model…

From the perspective of looks, would you find the look of CF weaves on the wheel appealing? It definitely makes the wheel harder and more expensive to make. For me personally it looks odd. I would prefer the look of a standard wheel in silver with all the benefits of CF one. Maybe the barrel from inside in CF weave would be nice touch.

Technically for offset, anything is an option, that’s why I am trying to discuss it here.

BMW themselves made hybrid CF wheel with aluminum spokes but the cost saving per set is just 7kg and the price is/was atrocious. Not worth IMO. Weight savings here would be around 14-16kg per set.

https://www.turnermotorsport.com/p-390839-f8x-m3m4-gts-m-carbon-wheel-set/

[usdmej]

Would 18x10+25 be an option? .

i think this is the point where you start losing the more casual E46 owners and only the track junkies/"fitment" guys would be interested

opening yourself up to E9X guys would be huge though

[cornerbalanced]

i think this is the point where you start losing the more casual E46 owners and only the track junkies/"fitment" guys would be interested

opening yourself up to E9X guys would be huge though

Agreed, but I’m not sure the “casual E46 owner” market would over weigh the E9x M3 market. Not sure how many casual E46 owners would even want carbon wheels to begin with, would seem odd to me if they did—but would love for others to chime in.

[nextlvel]

Agreed, but I’m not sure the “casual E46 owner” market would over weigh the E9x M3 market. Not sure how many casual E46 owners would even want carbon wheels to begin with, would seem odd to me if they did—but would love for others to chime in.

I agree with this sentiment, not wanting to "ostracize" the more casual e46 m3 owners seems odd to me because why would they be in the market for CF rims lol. I agree with cornerbalanced about e9X and e46 cross platform fitment, I have a few friends with that chassis who would definitely be interested in this.

Albeit this is just my own personal anecdote.