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BMW M2 Forum > BMW M2 CS Model > BMW M2 CS CFRP roof weave issues: "Garching, we have a problem" ?

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      10-14-2020, 05:29 AM   #67
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Quote:
Originally Posted by AUSf22 View Post
Quote:
Originally Posted by e92ben View Post
There ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
I'm afraid your guess or assumption does not equate to it being true.

The roof is an integral part of the M2CS and is not like "every other" carbon roof.. as we have mentioned to you throughout the thread a few times...
Quote:
Originally Posted by Davil View Post
Quote:
Originally Posted by e92ben View Post
There is ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
https://www.bmwblog.com/2020/06/21/b...nical-details/

"For the M2 CS, the Germans developed their own unique roof, which is a structural part of the bodywork! This is different from the way aftermarket solutions are available in the market, or even the M Performance solution"

Lots of info on this.
Quote:
Originally Posted by Artemis View Post
Quote:
Originally Posted by e92ben View Post
There ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
As noted in the first post of this thread, the BMW M2 CS features a new type of CFRP roof:
"The new roof, with its sandwich design, makes the body more rigid and appears to have been cut from the same mould as the rest of the car; no trim strips are needed, meaning no visible join[t]s either. This has the additional effect of enhancing acoustics, both inside and outside the car. And dispensing with the customary roof bows and insulation also saves weight. Together with the lighter bonnet, this serves to lower the vehicle's centre of gravity, resulting in even better driving dynamics."
(source: BMW press materials - see here)
Furthermore, the M2 CS roof features no roof rack anchorage points (roof drip rail with flaps).
Quote:
Originally Posted by hansomatic View Post
Quote:
Originally Posted by Igor_M5 View Post
BMW CF roofs have always been (up until the M2CS) plain weave 1x1, all the M "performance" bits have always been 2x2 twill weave, something that bothered me so much ever since the E9x gens when owners fitted non matching CF mirror caps, even tho it was a BMW option.
The M2CS does have plain weave CF on roof. Its just on the bottom side of the sandwich so you can't see it.
So. Much. Misinformation in this thread, it's unbelievable.

M2CS roof has plain weave on top and bottom, using two different types of weaving structures. Top is a UI tape (unidirectional fibers measured in the thousands) laid in a plain twill weave, bottom appears to be a 3K UI (much finer, denser form, being substituted for the cross reinforcement braces)

M2CS roof is as much part of the chassis as a prosthetic limb is to our bodies.
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      10-14-2020, 05:48 AM   #68
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Quote:
Originally Posted by Igor_M5 View Post
So. Much. Misinformation in this thread, it's unbelievable.

M2CS roof has plain weave on top and bottom, using two different types of weaving structures. Top is a UI tape (unidirectional fibers measured in the thousands) laid in a plain twill weave, bottom appears to be a 3K UI (much finer, denser form, being substituted for the cross reinforcement braces)

M2CS roof is as much part of the chassis as a prosthetic limb is to our bodies.
None of us have said it's part of the chassis, we've all said it's part of the bodywork.

Only the e92ben chap has claimed this roof is easy to remove and re-fit and when we told him it's definitely not that easy or like the other carbon roofs on the previous cars, he's then claimed its not part of the chassis ... (no one has said it was part of the chassis in the first place )
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      10-14-2020, 05:51 AM   #69
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Quote:
Originally Posted by drgmt View Post
Carbon fibre roofs have to be covered in ppf and then ceramic coated for optimal protection. Otherwise they will deteriorate when parked outside in harsh climates.
If you live in Australia and love your car you don't park outside of cover aside from brief periods. So It's a moot point.
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      10-14-2020, 05:56 AM   #70
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Quote:
Originally Posted by Igor_M5 View Post
So. Much. Misinformation in this thread, it's unbelievable.

M2CS roof has plain weave on top and bottom, using two different types of weaving structures. Top is a UI tape (unidirectional fibers measured in the thousands) laid in a plain twill weave, bottom appears to be a 3K UI (much finer, denser form, being substituted for the cross reinforcement braces)

M2CS roof is as much part of the chassis as a prosthetic limb is to our bodies.

Quote:
Originally Posted by e92ben View Post
There ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
Quote:
Originally Posted by Davil View Post
https://www.bmwblog.com/2020/06/21/b...nical-details/

"For the M2 CS, the Germans developed their own unique roof, which is a structural part of the bodywork! This is different from the way aftermarket solutions are available in the market, or even the M Performance solution"

Lots of info on this.
Quote:
Originally Posted by Artemis View Post
As noted in the first post of this thread, the BMW M2 CS features a new type of CFRP roof:
"The new roof, with its sandwich design, makes the body more rigid and appears to have been cut from the same mould as the rest of the car; no trim strips are needed, meaning no visible join[t]s either. This has the additional effect of enhancing acoustics, both inside and outside the car. And dispensing with the customary roof bows and insulation also saves weight. Together with the lighter bonnet, this serves to lower the vehicle’s centre of gravity, resulting in even better driving dynamics."
(source: BMW press materials - see here)
Furthermore, the M2 CS roof features no roof rack anchorage points (roof drip rail with flaps).

Quote:
Originally Posted by AUSf22 View Post
I believe the m2 cs roof is very different and is part of the body as a whole with no structural beams like other carbon roofs.

Replacement for it is certainly not easy.
No one's talking about the chassis?
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      10-14-2020, 06:00 AM   #71
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Quote:
Originally Posted by AUSf22 View Post

No one's talking about the chassis?
Yes. This is.... weird.
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      10-14-2020, 06:54 AM   #72
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Quote:
Originally Posted by Igor_M5 View Post
Quote:
Originally Posted by Artemis View Post
Quote:
Originally Posted by e92ben View Post
There ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
As noted in the first post of this thread, the BMW M2 CS features a new type of CFRP roof:
"The new roof, with its sandwich design, makes the body more rigid and appears to have been cut from the same mould as the rest of the car; no trim strips are needed, meaning no visible join[t]s either. This has the additional effect of enhancing acoustics, both inside and outside the car. And dispensing with the customary roof bows and insulation also saves weight. Together with the lighter bonnet, this serves to lower the vehicle's centre of gravity, resulting in even better driving dynamics."
(source: BMW press materials - see here)
Furthermore, the M2 CS roof features no roof rack anchorage points (roof drip rail with flaps).
So. Much. Misinformation in this thread, it's unbelievable.
M2CS roof has plain weave on top and bottom, using two different types of weaving structures. Top is a UI tape (unidirectional fibers measured in the thousands) laid in a plain twill weave, bottom appears to be a 3K UI (much finer, denser form, being substituted for the cross reinforcement braces)
M2CS roof is as much part of the chassis as a prosthetic limb is to our bodies.
Unclear if you referred to my quote: as indicated, it's from the BMW M2 CS press materials (see here):

Name:  BMW_M2_CS_CFRP_Roof.jpg
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      10-14-2020, 07:05 AM   #73
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The CS roof is a structural member, otherwise it couldn't contribute to body stiffness. Therefore it is part of the body/chassis. Not sure where the confusion is.

(maybe confusion is around the mixed terms. Body or chassis is usually referring to structural load bearing, torsional rigidity, or stressed member portions of the car. The "frame" in the old days or on portions of trucks, monocoque, tube chassis, or unibody depending on construction. "Bodywork" refers to covering panels - fenders, hoods, trunk lids, doors, etc.)
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      10-14-2020, 07:12 AM   #74
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I'll summarize why this thread has gone to this. It hit the front page. People click the link. Only scroll through the photos. Gasp in horror and then type the first opinion they arrive at.

Artemis' post was quite clear on the differences of the M2cs roof. As was BMW in their press release. I think a lot of people here are associating the F80 chipping photos with the title of the thread.

I thought I read that people that are actually taking deliveries now don't have any issues? Would be great to start a poll or something for actual owners.
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      10-14-2020, 09:06 AM   #75
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Quote:
Originally Posted by TCBavarian View Post
I'll summarize why this thread has gone to this. It hit the front page. People click the link. Only scroll through the photos. Gasp in horror and then type the first opinion they arrive at.

Artemis' post was quite clear on the differences of the M2cs roof. As was BMW in their press release. I think a lot of people here are associating the F80 chipping photos with the title of the thread.

I thought I read that people that are actually taking deliveries now don't have any issues? Would be great to start a poll or something for actual owners.
Here you go

https://f87.bimmerpost.com/forums/sh....php?t=1766380
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      10-14-2020, 09:07 AM   #76
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Quote:
Originally Posted by Turbomeister View Post
My guess is that every M2 CS has those imperfections , but not at the same places. Of course its not a deal braker , and it would rather be perfect than "unique" , but now its over , just take that approach , it was first tested on the M2 CS , each car/roof is unique with those small imperfections. Coming from the OG M2 , i love the CFRP roof , looks like a racing flag ! by the way , those imperfections are so minimal in reality , and i also have to admit that the 1x1 weave on the M2 CS is much better looking than the 2x2 . I will provide more photos of the roof tomorrow.
Attachment 2435412
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      10-14-2020, 10:22 AM   #77
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Quote:
Originally Posted by e92ben View Post
Quote:
Originally Posted by AUSf22 View Post
Quote:
Originally Posted by e92ben View Post
Quote:
Originally Posted by AUSf22 View Post
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Originally Posted by e92ben View Post
Quote:
Originally Posted by medphysdave View Post
If my M2CS has any roof defects I'll certainly have a conversation with BMW USA. We don't really have the option to have another car built, or have the roof replaced. Hopefully no one is seeing this on the non press cars.
Roof replacement is so easy.
Hm, not for the M2 CS.

It is not like the other carbon roofs
I'm pretty sure IND can source them from bmw. If you have an issue with them they are easily replaced. Bmwna would forsure do it.
I believe the m2 cs roof is very different and is part of the body as a whole with no structural beams like other carbon roofs.

Replacement for it is certainly not easy.
There ZERO chances it's part of the chassis. It's literally glued on like every other carbon roof Bmw has made.
Looks like someone didn't read the thread and just made a baseless claim...this never happens. 😤
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      10-14-2020, 11:24 AM   #78
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I would have a serious OCD episode if the CF roof on my M3CS started cracking and peeling. Lol. I would disagree with those that say the weight savings does not count. I don't know what the difference is but that's a large piece of sheet metal and it has to be fairly significant. It's also at the very top of the car.

Case in point. I strap a hard travel case to the back rack of my KTM 1090R. It weighs about 6 lbs when full of "stuff" and it's basically mounted at the highest point of the bike. My friend has the exact same bike but his soft case's (2) are mounted on the sides and about 10 inches lower. Just standing the bike up off it's kickstand mine feels 20lbs heavier. Keeping sprung weight low is important when tossing a car (or bike) around.
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      10-14-2020, 11:44 AM   #79
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I would definitely lose my shit over something like this if I was getting an M2CS.

It's such a special car, and made in limited numbers...how in the hell does that sort of defect make it through the quality control process before the car leaves the factory?
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      10-14-2020, 11:52 AM   #80
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Here's mine... are they checking the roof right now?
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      10-14-2020, 12:08 PM   #81
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The only tiny imperfections on the whole roof are on the left side in the middle almost . But you cannot see them even if you are close to the car in real life . You may see the "imperfection" but when you move a little hit and changes colour , seems normal . Honestly , i dont care about those imperfections , are so so tiny , in a roof that seems so beautiful , racing flag boxes , making great contrast with the colour of the car.

Each roof is different then , so each roof is unique . But , those imperfections , really are so few and small , but also cool since it seems like its handmade and they made each roof different ! It doesnt affect the car image at all !

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      10-14-2020, 12:29 PM   #82
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Quote:
Originally Posted by Higgs Boson View Post
Here's mine... are they checking the roof right now?
See 03:20 to 03:30 and 08:00 to 09:00:

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      10-14-2020, 01:33 PM   #83
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I may have missed an important post, as - I confess - I just skimmed the Thread: The M2 - in common with most modern cars - has a monocoque chassis in which all parts of the body structure (and some bolt on braces) form part of the chassis. So, if this replaces just the roof skin, it's likely to be cosmetic. If it replaces the braces between the roof pillars as well it may still be cosmetic, but is also structural.

In the meantime, here's a couple of links to help the argument along.

https://www.realoem.com/bmw/enUS/sho...diagId=41_2163

https://www.realoem.com/bmw/enUS/sho...diagId=03_0183
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      10-14-2020, 01:44 PM   #84
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Okay. Bodyshell is the chassis.

So, how does the construction of the CS bodyshell differ?
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      10-14-2020, 01:52 PM   #85
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Remind me: why does it matter if it's part of the body or the chassis? It's lighter and it's on top. Good place to reduce weight.
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      10-14-2020, 01:55 PM   #86
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I had replied and then deleted a comment because I found that there are quite a few sources that define monocoque the way you interpreted it, which is not how I learned it in school - the outer skin has to be the stressed member is the simplistic explanation. I'd still call the M2 a unibody car, but seems like there is room for argument.

The diagrams and info would indicate that the difference is that all M2s have "something" assembled between the window/door frame arches to connect those portions of the body for rigidity. In a regular M2 it is riveted and glued steel beams, on the CS it is the carbon roof panel.
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      10-14-2020, 01:57 PM   #87
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Quote:
Originally Posted by jmg View Post
Remind me: why does it matter if it's part of the body or the chassis? It's lighter and it's on top. Good place to reduce weight.
Because of the cosmetic issues and discussion around replacing the part. On M3's (including the CS and the heritage) and M2's previously it has just been a skin panel that is not structural. Not much worse than replacing a fender etc. On the CS it is installed from the inside from the info released, and is a structural component. It's not something the dealer or any old body shop is going to be doing basically.
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      10-14-2020, 02:03 PM   #88
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Remind me: why does it matter if it's part of the body or the chassis? It's lighter and it's on top. Good place to reduce weight.
Because of the cosmetic issues and discussion around replacing the part. On M3's and M2's previously it has just been a skin panel that is not structural. Not much worse than replacing a fender etc. On the CS it is installed form the inside from the info released, and is a structural component. It's not something the dealer or any old body shop is going to be doing basically.
I understand that. What I don't understand is why we are arguing about the semantics of it. Structural or not, repairs will be determined by the reality of how it is installed, not by what words a press release used.
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