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Discussion Starter #1
OK, what's the deal with frameless doors? Mercedes is making this a sales point in their sales brochure. Why? What am I missing? Are they just looking for extra filler in their brochure? I don't get it.

I would imagine a framed door (where the window is entirely encased in a metal frame on the door) is stronger and better for weather proofness. I think it would form a tighter seal and seal the window glass better than a framless design.

Maybe I'm over thinking this. Does Mercedes usually put these frameless designs in their cars? I know lots of American cars in the 60's and 70's had framless designs, but that's a car era I wouldn't exactly look towards for quality/design cues. Any thoughts?
 

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OK, what's the deal with frameless doors? Mercedes is making this a sales point in their sales brochure. Why? What am I missing? Are they just looking for extra filler in their brochure? I don't get it.

I would imagine a framed door (where the window is entirely encased in a metal frame on the door) is stronger and better for weather proofness. I think it would form a tighter seal and seal the window glass better than a framless design.

Maybe I'm over thinking this. Does Mercedes usually put these frameless designs in their cars? I know lots of American cars in the 60's and 70's had framless designs, but that's a car era I wouldn't exactly look towards for quality/design cues. Any thoughts?
A lot of cars have them as far as I know, seems more like filler to me as well. I don't think its anything revolutionary.
 

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My 370z is frameless and the windows go down/up when you open/close the door to release the pressure inside the cabin. I believe the CLS does this too...
 

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Sports cars & coupes along w/ coupe-style sedans (w/ "fastback" roof styling) seem to have frameless door as design characteristic.

With that said, my bulbous ES300 from the mid '90s also had frameless doors, so go figure! :D
 

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Back in the 1950s and 1960s, four-door cars with frameless doors and no B pillars were known as "hardtops," as opposed to sedans. The idea was that, with all the windows down, the hardtop gave a much more open feeling than the sedan. Hardtops also lacked the structural rigidity of sedans and quickly developed lots of squeaks and rattles. Engineers -- my father, for example -- hated them.

I would imagine that frameless doors are also cheaper to build, so using them on the CLA may be one way MB is keeping down its costs to hit its sub-$30K base price point.
 

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OK. I just had a scary thought because I have no experience with frameless doors...someone please tell me it'll be OK. What kind of risk to damaging the window will there be when it's winter time and there is a sheet of ice all over my car causing me to have to scrape and yank open my door to break it free from the ice so I can get in? Having a door frame and yanking the door open to get in doesn't concern me, but thinking more about the frameless doors is starting to concern me. Someone with experience please reassure me that it'll be OK. :eek:
 

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It's fine. Subarus have frameless doors and are known as winter cars. You just have to be careful. But, in general, try to avoid yanking your doors to free from them from ice. That's what ice scrapers were made to do. Keep one in your trunk. :)

-Eric
 

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I've only ever owned Audi's and VW's which had frames.
I am in the same situation. I tried CLA for one day, and in the beginning it was very unusual. I realized that I use to close the door using the frame on my Audi and my VW. Now I had to hold my hand further down to close the door. I am also concerned about the winter, and how this window function works in practice. Up here in the northern Europe the winter can last for 5-6 months. The glas is lowered about 10 mm down when you open the door, so if there is ice between the glas and the door it might be problematic. At night I put the CLA under the carport, but I have no garage outside the office so I think it is important to make the car ice and snow-free before opening the doors.
 

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Discussion Starter #16
The more I think about it, the whole 10 mm lowering of iced-up windows does concern me a little bit. I have a nice warm garage at home but my car will see horrific ice and all kinds of frozen rain while it sits in my workplace parking lot.

I'm an engineer myself and I would hope MB engineers thought this scenario through when designing their design. I actually have had my Audi windows freeze up (and that was after I scrapped away all the exterior ice). I would hope the Mercedes' motor doesn't get damaged when the windows are frozen. And I would hope the door opens and closes properly when the windows are frozen.

However I think one of the main reasons for the 10 mm movement is because the pressure is so tight inside the cabin it's meant as a pressure release, so that the door can close. I once had a VW New Beetle that was so tightly sealed, I could not close the truck no matter how much force I used. I would try slamming it 50 times and it wouldn't latch. It's wasn't fun. If I left one window slightly open, then it latched OK. I think BMW currently uses a similar 10 mm drop method due to their tight pressure. However BMW doesn't have frameless doors (at least I don't think so).
 

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Guys, I don't mean to dismiss your concerns but this isn't the first car with frameless windows to spend time in ice and snow and it won't be the last. For that matter, any windows/doors will freeze if the weather is bad enough. If you've lived in a wintery climate long enough you know this. Find the right mix of sideways frozen rain and ice hitting a car that is exposed to the elements in a parking lot or on the street, mix it with time and you'll have an icy mess for any car regardless of whether the windows are frameless or not.

If you live in the Northeast, just think about the sheer number of Subarus onour roads. Most, if not all of them have frameless windows. They are winter cars almost by definition. Most convertibles have frameless windows. Lots of economy cars have them, too. It just isn't that big of a deal if you're careful and use an ice scraper.

Also, keep in mind that Mercedes, like every manufacturer, winter tests its cars in extreme conditions. They've seen the equivalent of years of ice and snow before they ever hit the market.

I've had the framed doors on my Volvo freeze up at my office in a bad ice storm. The horrible separation sound I heard as I opened the door and slowly separated it from the rubber weatherstripping was like nails on a chalkboard to me but the car was fine. With frameless windows you just have to be sure to break the ice to ensure there isn't undue pressure on the windows. It's just common sense stuff you'd probably do anyway.

-Eric
 

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Discussion Starter #18 (Edited)
Perhaps I should have been clearer. The frameless design by itself doesn't interest me. It's the combination of BOTH frameless and the 10 mm motorized drop that intrigues me.

Granted there are a lot of cars out there that are frameless. And granted there are other cars out there that have the 10 mm motorized drop. But other than BMW convertibles I can't think of many cars that have BOTH a frameless design and a 10mm motorized drop.

Now I'm not an expert on every car in the world and it's probably really nothing to worry about. But I enjoy examining technical things inside and out and understanding how they work. I'd like to ask the MB engineers how they can design a 10 mm motorized drop knowing that in some instances it won't happen when the windows freeze up. So then I gotta wonder how critical is that 10 mm drop really. And it makes me hope the motor has an over-ride clutch in it, because otherwise it could get damaged after repeated opening and closing of the door with frozen windows. Here's a thought, maybe the MB engineers designed the 10 mm drop to disable itself if the outside temp gets below 32 degrees. I'm just thinking out loud here.
 

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Perhaps I should have been clearer. The frameless design by itself doesn't interest me. It's the combination of BOTH frameless and the 10 mm motorized drop that intrigues me.

Granted there are a lot of cars out there that are frameless. And granted there are other cars out there that have the 10 mm motorized drop. But other than BMW convertibles I can't think of many cars that have BOTH a frameless design and a 10mm motorized drop.

Now I'm not an expert on every car in the world and it's probably really nothing to worry about. But I enjoy examining technical things inside and out and understanding how they work. I'd like to ask the MB engineers how they can design a 10 mm motorized drop knowing that in some instances it won't happen when the windows freeze up. So then I gotta wonder how critical is that 10 mm drop really. And it makes me hope the motor has an over-ride clutch in it, because otherwise it could get damaged after repeated opening and closing of the door with frozen windows. Here's a thought, maybe the MB engineers designed the 10 mm drop to disable itself if the outside temp gets below 32 degrees. I'm just thinking out loud here.
Nothing wrong with thinking out loud and, you're right (IMHO) that its not as carefree as framed windows. But lot of cars have this feature to ensure that the frameless windows form a watertight tight seal against the rubber and don't start separating from the body at high speeds. My Porsche Carrera drops its windows. My old Audi TT dropped its windows. I'm going to venture a guess that every high line convertible on the market in 2013 has this feature.

Back in 2002 when I bought my TT it was my daily driver year round. A significant amount of ice would have had to have accumulated for the windows not to go down. The first and last time it happened to me taught me to be aware of the ice accumulation and to make sure enough ice was removed before I opened the doors. When it happened the window made a thunk against the hard weatherstrip that overlapped it but the door opened without a problem. The only real problem was that it wouldn't close without breaking the ice because the window was still in the "up" position. It also taught me to keep an ice scraper in the trunk. :) lol I think the some tolerance for real life situations has been engineered into these features - or they'd constantly be replacing windows and you'd be reading complaints about the feature from automotive journalists based in Michigan and other cold climes.

-Eric
 

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It's just as protective against weather as framed doors. When you open the door, it unseals itself and when you close it, it reseals. The only difference is a better design
 
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