To B-Post or Not to B-Post in a coupe.

[Zafiro]

hehe! I`m not bashing. If you want proof I can post a link to an M3 convertible test where the testers noted torsional flex.

so you read it once and now you assume all M3 convertibles has this problem?? Why havent for instance Sportauto said anything about this?
I can understand the Cabriolet but the Coupe??? thats just weird.

 

[Osnabrueck]

The M3 convertible is even worse than the coupe...

Right. Because it's a convertible!

Likewise, the CLK convertible is even worse than the coupe. Makes sense, right?

But now the waters have been throughly muddied by throwing convertibles in the argument. We were just talking about cars with and without b-pillars - right?

 

[GTA45E]

Right. Because it's a convertible!

Likewise, the CLK convertible is even worse than the coupe. Makes sense, right?

But now the waters have been throughly muddied by throwing convertibles in the argument. We were just talking about cars with and without b-pillars - right?

Alright I`m guilty! I shouldn`t have bought the M3 droptop in the picture, lets just forget about it! I can`t find the link anyway!

The CLK droptop was noted as being one of the tightest droptops ever tested! Again no droptops!!

 

[St. Merc]

What are your thought about B-posts in coupes?

Coupe design flows better without B-pillars...See CL, CLK, etc.

 

[Matt]

I dont know what your talking about on M3's torsional rigidity issues as well. Never heard that. If you could post an article/ complaint to help us out, that would be great.

One thing though. Coupes usually spawn from sedans. The purpose of a sedan is to seat five people in comfort. When BMW or Mercedes makes a coupe from a sedan its purpose is to be more performance oriented because you dont have that comfort you would have in the sedan. So obviously the coupe should be more rigid than the sedan because its changing a luxury car to a performance car.

Now I dont care what you say, a fat C piller can never make up for a B piller on providing rigidty. Sure it can connect the bact to the front more strongly but it cant stop torsional flex like a B piller can, simply because its in the wrong place. Its just simple physics.

 

[GTA45E]

Now I dont care what you say, a fat C piller can never make up for a B piller on providing rigidty. Sure it can connect the bact to the front more strongly but it cant stop torsional flex like a B piller can, simply because its in the wrong place. Its just simple physics.

Yes it can!
torshional rigity requires much more than a b-post in a coupe. It`s laso requites cross members in the underbody chassie as well. It all depends on how and where these members are located. I believe some car designers use B-posts for cost cutting, why? It`s much cheaper to design a winddow in that area that pops out than to have the window roll down.

 

[Zafiro]

Torshional rigity requires much more than a b-post in a coupe. It`s laso requites cross members in the underbody chassie as well. It all depends on how and where these members are located. I believe some car designers use B-posts for cost cutting, why? It`s much cheaper to design a wind in that area that pops out than to have the window roll down.

you think a lot, care to provide with links about what you saying?
I know nothing about this stuff so obviosly I need a second opinion

 

[klier]

GTA, we already explained this to you in the other thread right? Why start a whole new thread stating the obvious?

'To B-Post or Not to B-Post' has everything to do with one's personal opinion about the looks and the performance of the car itself. Mercedes gives higher regard to the looks with it's coupes, BMW thinks the performance isn't up to par without a B (minus the 8-series of course)

 

[GTA45E]

you think a lot, care to provide with links about what you saying?
I know nothing about this stuff so obviosly I need a second opinion

That would require scans of a few MB brochures!

I have a tummy ache now and don`t feel too well

I can tell you this
I study the MB unit body designs and know that MB uses whats called
HSLA steel in critical areas like A and C-Pillars. Thats a low alloy steel and is extremely strong for critical design work. Thats why thay don`t use B-posts
in the CL and CLK.

 

[Matt]

Yes it can!
torshional rigity requires much more than a b-post in a coupe. It`s laso requites cross members in the underbody chassie as well. It all depends on how and where these members are located. I believe some car designers use B-posts for cost cutting, why? It`s much cheaper to design a winddow in that area that pops out than to have the window roll down.

Of course but the undercarriage (such as anti sway bars and struts) are for providing rigidity for the "unsprung weight" (the chassis), while B pillers are for providing rigidity to the body. Antisway bars arent going to stop the body from flexing, their soley meant to keep the frame balanced. B pillers will keep the left side of the car attached to the right and the roof attached to the body. You cant simply rely on the chassis to keep the body in check as well as the chassis, sure it will help though. Also BMW's have less body roll than MBs (alot less) so the argument that a B piller isnt needed is pretty weak.

 

[klier]

Yes it can!
torshional rigity requires much more than a b-post in a coupe. It`s laso requites cross members in the underbody chassie as well. It all depends on how and where these members are located. I believe some car designers use B-posts for cost cutting, why? It`s much cheaper to design a winddow in that area that pops out than to have the window roll down.

Now imagine all that above in a BMW, a car not known to cut costs on the driving experience, PLUS a B-Pillar.....
...sounds like a winner, right?

When Audi starts making coupes, I am pretty sure they will use B-pillars too. Audi's philosophy is much closer to BMW than MB, imho

 

[GTA45E]

Of course but the undercarriage (such as anti sway bars and struts) are for providing rigidity for the "unsprung weight" (the chassis), while B pillers are for providing rigidity to the body. Antisway bars arent going to stop the body from flexing, their soley meant to keep the frame balanced. B pillers will keep the left side of the car attached to the right and the roof attached to the body. You cant simply really on the chassis to keep the body in check. Also BMW's have less body roll than MBs (alot less) so the argument that a B piller isnt needed is pretty weak.

I know, but you forgot the crossmembers in the unitbody frame. Those are very critical in reducing torshional flex. This also depends on how good the designers are with their work. Besides that body roll has nothing to do with body flex. The CL500 and 600 have less body roll than any other coupe I`ve ever seen, why? ABC.

 

[Centurion]

When it comes to large coupes they look best without a B-pillar. Small coupes, I could care less.

 

[GTA45E]

Now imagine all that above in a BMW, a car not known to cut costs on the driving experience, PLUS a B-Pillar.....
...sounds like a winner, right?

When Audi starts making coupes, I am pretty sure they will use B-pillars too. Audi's philosophy is much closer to BMW than MB, imho

It will be interesting to see what direction Audi takes when designing coupes!

 

[Osnabrueck]

Don't worry, they never will.

If we count the new TT there's no b-pillar, but the greenhouse is quite small and the rear-quarter window tiny. The Z4 Coupe, on the other hand, sports a b-pillar (that's a gimmie).

Come to think of it there is not one Mercedes 2-door car that uses a B-Post. Yet the body structure is very rigid and strong!

....I was refering to the more upscale models. I should have made that clear!

Does the SLR qualify as an upscale model? Or does it get a pass for being a 2-seater?

Have we been able to establish the benefits of the b-pillar yet? It makes for a stiffer car. You can add everything and the kitchen sink to a car's supports and underbody, but it's no replacement for a B' supporting the car's midsection.

Mercedes creates cars sans a b-pillar because it looks good, and makes for a more luxurious car. On the downside, it makes for a more expensive car, and takes a toll on the body's stiffness.

Personally, I'd love for BMW to create a 3er sans b-pillar, but we'd be talking about a sacrifice in driving dynamics, and an inflated price tag. For those who want all that pillarless gravy, the 3er cabrio should do - I, for one, am salivating at the prospect.

 

[GTA45E]

Does the SLR qualify as an upscale model? Or does it get a pass for being a 2-seater?
Have we been able to establish the benefits of the b-pillar yet? It makes for a stiffer car. You can add everything and the kitchen sink to a car's supports and underbody, but it's no replacement for a B' supporting the car's midsection.

Mercedes creates cars sans a b-pillar because it looks good, and makes for a more luxurious car. On the downside, it makes for a more expensive car, and takes a toll on the body's stiffness.

Personally, I'd love for BMW to create a 3er sans b-pillar, but we'd be talking about a sacrifice in driving dynamics, and an inflated price tag. For those who want all that pillarless gravy, the 3er cabrio should do - I, for one, am salivating at the prospect.

But the SLR is a 2-seater, it makup is completely different! Look at the
under carrage of the SLR, thay are very large and thick!! the SLR has the tightest body structure in the world noted some testers.

SLR aside, I have never herd a test where the CLK and CL ever suffered from torshional flex, I read a lot of magazines.


Osna now your guilty, the SLR is a 2 seater, it`s not fair to compare this to a 4-seat coupe!

 

[klier]

Don't worry, they never will.

Never will what Osna? Audi never making coupes or B-pillars?
Coupes they will make, I believe the A5 will be a 4 door coupe right?

GTA, I once touched and felt the structure and material of that stripped SLR at the IAA in Frankfurt in either 2001 or 2003. It was magic, and the most high thech car I have ever seen in such a 'naked' form

 

[warot]

Without B pillars, the structural rigidity might have to be tightened from somewhere else. That might also mean extra weight. Look, no offense, but Mercedes Benz are not known to be the best handling cars. Blame it on the suspension, blame it on the weight, but I think the priorities between BMW and Benz are completely different.

 

[wltsm]

I prefer the looks of a car without B pillers, but am sure a car with them are stiffer!

I like the idea though on a coupe dropping all the winds, and having that huge open space!

 

[GTA45E]

Look, no offense, but Mercedes Benz are not known to be the best handling cars. Blame it on the suspension, blame it on the weight, but I think the priorities between BMW and Benz are completely different.

That doesn`t explain how the SL55 no B or C-Pillars beat the M6
with B and C Pillars around the track does it!