[MR.]

Guys, I have been searching the forum and I don't really have the answer yet. An answer to a question that three people including me are trying to answer together. The main question is what size wheels to buy and more importantly do they fit, since buying them is not gonna be cheap.

We all want to fit BBS FI R wheels and we are all looking into fitting a new coil-over suspension as well. The question is what size will fit the wheel arches of the M2C since we are going to lower our car, but we don't want to touch the arches.

The options are:

19x9,5 with an offset of 22
19x10,5 with an offset of 35

Or

20x9,5 with an offset of 22
20x10,5 with an offset of 35

From a tire perspective I think we would want to go a touch wider. Like 255 at the front and 275 at the rear. For us three the question is; who has the golden comment that helps us knowing if this fits and what we should choose?

Thanks guys! And if I did not search well enough, sorry for that, but did not find an answer to my question which combines all this info.

MR

[DanG]

Lots of people run 255/35/19 and 275/35/19 on stock rims. This is the size M3 and M4 came with on the same rims.

[SeanWRT]

This is the "Golden Comment" as you call it - If you're lowered and stay stock alignment with FI-R, anything bigger than factory tire will rub both at front and rear.

255 front and 275 back easily rub at speed bumper, either in 19 or 20. And at front, it rubs badly just with full steering turn.

No mention the rear goes outside of the fender by 3mm.

[MR.]

Originally Posted by SeanWRT

This is the "Golden Comment" as you call it - If you're lowered and stay stock alignment with FI-R, anything bigger than factory tire will rub both at front and rear.

255 front and 275 back easily rub at speed bumper, either in 19 or 20. And at front, it rubs badly just with full steering turn.

No mention the rear goes outside of the fender by 3mm.

That is what I wanted to hear!

Do you think it is smart to go higher offset to move the wheels more inwards on the FI-R? I would go stock size rim and stock size wheels both front and rear, just make sure the offset puts them more inside the arches.

I saw some photos and I did not like what I say. Wheels tend to stick out a bit more due to the lower offset than stock (-7 and -5). Of course, this all depends on the space I have with those massive brake calipers of the M Sport kit.

Also, 20 inch with lowering possible? I have a hard time thinking that this is even possible. If I go for a AST kit I will definitely go a touch lower, but then the question does 20 inch fit and if I go for a higher offset does 20 inch with a higher offset work.

MR

[SeanWRT]

BBS doesn't do custom fitment often, so if somehow you can special order, go for it. My understanding is that FIR is very fitment limited due to their design (holes on the spokes). Logically, they would have already made M2 fitment if that's possible.

Either in 19' or 20', FI-R fitment for F80/82 is 13mm (7+6) poker over stock at front and 11mm (5+6) at back, ET and J combined. M2 has a surprising low tolerance of fitment, FIR's poser fitment would be fine on street though.

With 20', the taller tire can become a more serious concern. For example, 763m with 285/30/20 can rub at back when lowered, despite of having stock fitment.

There is a fascination of European and American people with FI-R, apparently out of BBS German marketing. At the beginning, they even mislead people into believing FIR is made in Germany...Not until in early 2017, German can't keep lying and take credit for it anymore. BBS Japan made it clear to public that every single forged wheel under BBS brand has been made in Japan. FI-R started to show on BBS Japan website, and can be ordered in their traditional diamond finish.

Truth to be told, FI-R is not even at the top of BBS line, Japan made a lot of incredible wheels long back. I explained a bit to a F80 board see link below:

https://f80.bimmerpost.com/forums/sh....php?t=1188877

And my RI-D in diamond black say hi.

The front is 2mm inside of fender and back is 3mm. From the most of angles, they're perfect aligned to the fender. The most aggressive fitment to have when lowered, without rubbing under any condition.

[MR.]

Great reply once again! Thank you for this.

I have spoken to BBS and for now I will go lower, fit the 19 inch wheel and keep the stock wheel size. I am not going to try it any different for now.

There are a few partners of BBS that are running FI R with stock tires and all kinds of lowering kits, and it seems to go well. No comments on it.

These photos above are RI D, I presume? They look quite similar to FI R but don't have the holes in the spokes.

MR

[ZM2]

Hey SeanWRT what are the specs on your wheel/tire set above?

I run 265/295/30/19 R comps on 19x9.5/10.5 for the track, but I’m thinking about trying those tire sizes on the stock wheels and 4S’s for the street to get more grip with the Dinan Turbo & BM3 Stg 2H power.

[HScomp_M2]

I think the FI-R fits absolutely perfect on the M2 without any spacer and from what I keep reading, the stock tires work the best on lowered car. In my opinion they do not look to "stretched out" either. Handmadeshifts is running them and detailers domain also posted up a new HS comp M2 with them on as well without being lowered.
https://www.detailersdomain.com/blog...m2-competition

[ZM2]

I’m sure I’ll ruffle some feathers here, but I’ve been against FI-R’s on the M2 from day one.

Looks are looks and everyone has an opinion, but the offsets make zero performance sense for the M2. You’re forced to run skinny stock tread on a wider wheel. Why compromise on on grip with such an expensive wheel?

I can put so much more rubber on my “heavy” 23-lb 19x9.5/10.5 +33/45 VMR’s that the lighter FI-R’s (which are 5x more expensive!) can’t come close to matching the grip/speed of my wheel/tire set.

Plus, who wants to run a $2k wheel on track? It’s just going to get trashed. I guess people just buy these wheels for looks, which don’t do it for me either.

[MR.]

Originally Posted by ZM2

I’m sure I’ll ruffle some feathers here, but I’ve been against FI-R’s on the M2 from day one.

Looks are looks and everyone has an opinion, but the offsets make zero performance sense for the M2. You’re forced to run skinny stock tread on a wider wheel. Why compromise on on grip with such an expensive wheel?

I can put so much more rubber on my “heavy” 23-lb 19x9.5/10.5 +33/45 VMR’s that the lighter FI-R’s (which are 5x more expensive!) can’t come close to matching the grip/speed of my wheel/tire set.

Plus, who wants to run a $2k wheel on track? It’s just going to get trashed. I guess people just buy these wheels for looks, which don’t do it for me either.

They will never be my track wheels. They are my summer wheels. The 788M's are my winter wheels. If I want track wheels, I will get something else that is a lot cheaper.

MR

[SeanWRT]

Originally Posted by MR.

Great reply once again! Thank you for this.

I have spoken to BBS and for now I will go lower, fit the 19 inch wheel and keep the stock wheel size. I am not going to try it any different for now.

There are a few partners of BBS that are running FI R with stock tires and all kinds of lowering kits, and it seems to go well. No comments on it.

These photos above are RI D, I presume? They look quite similar to FI R but don't have the holes in the spokes.

MR

The picture is my car on RI-D.

My thoughts on stock tire on FIR - Star spec 265mm is really 255mm, let me show you that in the picture attached. And, even the real generic 265mm/10J is on the stretched side. Imagine 255m on 10.5J. Really FI-R is F80/82 exclusive, it's not made for M2.

More importantly, M2C has noticeably more power than OG and thus is more traction limited. I'd let wheel go if it's holding me back on performance. BBS isn't really a poser wheel brand.

Additionally, I explained the difference between RI-D and FI-R somewhere else and I quote as following. It looks to me American and European people really need to get to know BBS better.

Originally Posted by SeanWRT

The primary difference is in the material.

RI-D uses the superior 7 series aluminum alloy which they trademark as Extra-Super Duralumin, compared to the FI-R made of normal 6 series aluminum.

Learn about Duralumin
https://en.m.wikipedia.org/wiki/Duralumin
https://www.azom.com/amp/article.aspx?ArticleID=8073

On top of the already stronger and lighter duralumin (than aluminum), BBS further tweaks the copper % to find a bit extra strength and call it extra-super duralumin. There're 3 models from the lineup made of that material - RI-D (top dog), RZ-D (busy design and conservative fitments made for less performance oriented vehicles) and FR-D (BMW I8 only).

BBS range topping Street Wheels now have been FZ-MG (magnesium tech), RI-D (extra-super duralumin and lightweight design) and FI-R (extreme lightweight design).

FI-R fitment is very limited having to accommodate holes on the spokes. RI-D is much more flexible (tons of fitments) so deeper concave is possible if desired.

Design wise, FI-R spokes are noticeably sharper. RI-D is softer by comparison and flows a bit more. You can easily tell from the comparison picture attached.

The finishes that's been available at this point:
FIR - Diamond Silver (DS) and Diamond Black (DB).
RID - Diamond Silver (DS), Diamond Black (DB) and Matte Black (MB).
Don't let your dealer fool you. Other finishes can be specially ordered. Even frozen gold is optional should you give it a 3 month wait.

Both rims are ultra lightweight. Below is the weights of their comparable 19" fitment for F8X (front is still different in ET).
FI-R
FI137 19×9.5 22 5/120.0 72.5 7.5kg (16.5lbs)
FI138 19×10.5 35 5/120.0 72.5 8.1kg (17.8lbs)
RI-D
RI031 19×9.5 25 5/120.0 PFS 7.9kg (17.4lbs)
RI033 19×10.5 35 5/120.0 PFS 8.3kg (18.3lbs)

FI-R is easier to mass produce. As a result North America and Europe dealer networks carry way more FI-Rs. RI-D has always been made to order and thus is more exclusive worldwide. However, in Asia Pacific area, the popularity of the two rims in the F8X market are about equal.

[ZM2]

Definitely like the looks of the RI-D more!

[SeanWRT]

Originally Posted by ZM2

Plus, who wants to run a $2k wheel on track?

I do, among a lot others around

Our two local tracks (SH F1 and TM) don't have very rough shoulders. My HRE RS100M and RI-D handled that no issues haha

[ZM2]

Originally Posted by SeanWRT

I do, among a lot others around

Our two local tracks (SH F1 and TM) don't have very rough shoulders. My HRE RS100M and RI-D handled that no issues haha

Not all of us have access to an FIA Grade 1 track. Defintiely jealous!

Many of the tracks around here scratch and damage wheels all the time from misc track debris getting kicked up.

We even have to dodge deer at one of our tracks!

[ashtaron14]

SeanWRT

Are you running the 19x9.5 RI031/19x10.5 RI033 or the 19x9 RI049/19x10 RI049?

Thanks,
Sunny

[Andi-M2]

Originally Posted by SeanWRT

I do, among a lot others around

Our two local tracks (SH F1 and TM) don't have very rough shoulders. My HRE RS100M and RI-D handled that no issues haha

I do, also!

Running with Michelin Pilot Sport Cup 2 in standard size 245/265.

[ZM2]

Originally Posted by Andi-M2

I do, also!

Running with Michelin Pilot Sport Cup 2 in standard size 245/265.

Yeah, the BBS wheels don’t have the right offsets to maximize rubber on the car. Again, they don’t make any sense on the M2 for track performance, which is a shame bc their lightweightness isn’t getting put to good use.

A set of 265/295/30 4S’s on 19x9.5/10.5 wheels with the right offsets are probably quicker than 245/265/35 Cup 2’s, and 265/295/30 Cup 2’s on heavier wheels would absolutely thrash the 245/265/35’s on lighter wheels.

RI-Ds as a street wheel, sure. But, most all non-custom BBS’s do not have the right offsets to maximize performance for the M2.

[ashtaron14]

Originally Posted by ZM2

Yeah, the BBS wheels don’t have the right offsets to maximize rubber on the car. Again, they don’t make any sense on the M2 for track performance, which is a shame bc their lightweightness isn’t getting put to good use.

A set of 265/295/30 4S’s on 19x9.5/10.5 wheels with the right offsets are probably quicker than 245/265/35 Cup 2’s, and 265/295/30 Cup 2’s on heavier wheels would absolutely thrash the 245/265/35’s on lighter wheels.

RI-Ds as a street wheel, sure. But, most all non-custom BBS’s do not have the right offsets to maximize performance for the M2.

What would the right offset be?
19x9.5" ET28 and 19x10.5" ET40?

[ZM2]

Originally Posted by ashtaron14

What would the right offset be?
19x9.5" ET28 and 19x10.5" ET40?

Well, I can only speak from my experience.

First, if you have a lowered car and want to run 265 or 275/19 in the front and 295 or 305/19 in the rear without any issues, you need to go with 30 series tires (not 35) for the height of the tire to clear and not rub the fender liners.

Second, I think the ET window in the front is 27-33 and 43-48 in the rear. I base this on running 265/295/30/19 Trofeo R’s and 265/35 295/30/19 R7’s on ET33/45 wheels.

The Trofeo’s fit fine and the R7’s required a 3mm spacer in the front to clear the suspension. Overall, I had a few mm on either side of the tires to play with. All this depends on your camber settings, as well.

[SeanWRT]

Originally Posted by ZM2

Yeah, the BBS wheels don't have the right offsets to maximize rubber on the car. Again, they don't make any sense on the M2 for track performance, which is a shame bc their lightweightness isn't getting put to good use.

A set of 265/295/30 4S's on 19x9.5/10.5 wheels with the right offsets are probably quicker than 245/265/35 Cup 2's, and 265/295/30 Cup 2's on heavier wheels would absolutely thrash the 245/265/35's on lighter wheels.

RI-Ds as a street wheel, sure. But, most all non-custom BBS's do not have the right offsets to maximize performance for the M2.

The right fitment is one thing, the fitment to maximize the rubber is another.

BBS has good fitments for M2 though not with FI-R but I don't think anyone in the business makes M2 max rubber fitment off the shelf. That would be 9.5/10.5j and 30+/40+ET, which is very odd for any modern BMW.

I myself had doubts how big is big enough until realized that understeer is F8X inherent, with or without grippy tire at front. You can strap big tire to any car of from as low as 200hp and see lap time improvement. But there is a line to draw...There're very few cars out there, any car, using more than 245mm at front. And at just 400p people think 275mm at back is not enough for M2. What's wrong with us? That's hardly true, even if it is, we better reduce power/torque to not upset the chassis than max rubber at back to break the grip bias even more.

Personally I hold reservation with 30 series tires in 19" because being too thin alone can compromise grip (35 grips noticeable better than 30 at any given width), no mention of the harsh ride.

In ideal world, 245/285/35 probably is the best, performance wise, for any M2. But so many real world considerations (tire spec limit, rubbing when lowered, wheel fitment, front vs. back circumference ratio off, 285/35 too thick killing easthetic...) make 255/275/35 the way to go, for me.

[ZM2]

I agree with all that for the street. Altho, I’m still going to try 265/295/30 for my next 4S set to live the pros/cons.

For the track, 30 series is fine bc the track surfaces are generally smooth.

[MR.]

I can't go 30's here in town. My stomach would be between my ears.

For now I will go stock width on a 19 inch FI-R and then lower with a suspension kit.

I will dive into the RI-D as well to have a look what I can get in Europe.

MR