F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > BIMMERPOST Universal Forums > General BMW News and Cars Discussion > Why do higher end BMW's lower windows when doors are opened?
ARMA SPEED
Post Reply
 
Thread Tools Search this Thread
      03-17-2008, 01:37 PM   #23
veryhuman
Private First Class
Taiwan
4
Rep
112
Posts

Drives: 2005 Z4 2.5I
Join Date: May 2007
Location: Toronto

iTrader: (0)

Does the feature become a problem when you are waiting for tints to dry (2-3 days)?
Appreciate 0
      04-14-2008, 10:49 PM   #24
BloodShed
Registered
0
Rep
2
Posts

Drives: 2002 e46
Join Date: Apr 2008
Location: Central FL, USA

iTrader: (0)

It's true; this is only done on frameless door windows (such as most coupes). It started with higher class cars but is showing up on modern lower priced cars now.

Anyway, the main reason this feature is done is to deter theft. Because the window slides up into the frame when it closes, it seals the window. On frameless door windows that do not have this feature, it is possible to shove a wedge between the glass and the door frame. This could provide a few inches of gap to allow someone to disengage the door locks with a tool. Locksmiths often use this method on frameless windows.

Video of this:
http://www.expertvillage.com/video/2...tools-long.htm
Appreciate 0
      04-15-2008, 10:30 AM   #25
35past3
Private
0
Rep
56
Posts

Drives: 335i
Join Date: Dec 2007
Location: CT

iTrader: (0)

Quote:
Originally Posted by pokerface View Post
easier to shut the doors as it relieves a bit of air pressure
LOL
Appreciate 0
      04-15-2008, 10:33 AM   #26
35past3
Private
0
Rep
56
Posts

Drives: 335i
Join Date: Dec 2007
Location: CT

iTrader: (0)

Quote:
Originally Posted by BloodShed View Post
It's true; this is only done on frameless door windows (such as most coupes). It started with higher class cars but is showing up on modern lower priced cars now.

Anyway, the main reason this feature is done is to deter theft. Because the window slides up into the frame when it closes, it seals the window. On frameless door windows that do not have this feature, it is possible to shove a wedge between the glass and the door frame. This could provide a few inches of gap to allow someone to disengage the door locks with a tool. Locksmiths often use this method on frameless windows.

Video of this:
http://www.expertvillage.com/video/2...tools-long.htm
I disagree with you. The main reason for this is because if the window didn't lower it would keep rubbing the door seal, causing premature wear and tear. It has to raise into the door seal to form a tight bond to prevent excess cabin noise.

The feature has nothing to do with security. A thief will either cut the door seal or just break your window.
Appreciate 0
      04-15-2008, 07:46 PM   #27
BloodShed
Registered
0
Rep
2
Posts

Drives: 2002 e46
Join Date: Apr 2008
Location: Central FL, USA

iTrader: (0)

Quote:
Originally Posted by 35past3 View Post
I disagree with you. The main reason for this is because if the window didn't lower it would keep rubbing the door seal, causing premature wear and tear. It has to raise into the door seal to form a tight bond to prevent excess cabin noise.
My previous car was a '92 Celica which had frameless door windows. I owned that car for about 9 years. It did not have indexed windows (this window sealing feature) and it never had wear on the seals. The way the seal works is the window is simply pressed against it. I'm not sure what "rubbing" you expect.

I would agree that cabin noise would be greatly helped. That's also part of the design. However, why would this feature bother sealing the window when the car is off? Cars without this feature are just as water-tight so there's no need unless the car is on. In fact, it might actually help the life of the window regulator (a common failure) if it only engaged when the car was turned on.

Anyway, there's plenty of benefits. I just had to comment because no one else mentioned it. If you don't agree/believe me, that's fine.

Quote:
Originally Posted by 35past3 View Post
The feature has nothing to do with security. A thief will either cut the door seal or just break your window.
It's just a deterrent. There's always a way for a thief to get around it. The goal is to add enough obstacles that the thief no longer finds it worth the time/risk or moves onto another, easier target. Breaking glass tends to attract immediate attention. If they're stealing the car, those windows are also worth money. There's no point breaking the glass when it only takes 5-10 seconds insert a wedge and pop the locks silently.
Appreciate 0
      04-15-2008, 08:28 PM   #28
335xi
Private
3
Rep
92
Posts

Drives: 335xi
Join Date: Mar 2007
Location: Toronto

iTrader: (0)

Quote:
Originally Posted by 35past3 View Post
I disagree with you. The main reason for this is because if the window didn't lower it would keep rubbing the door seal, causing premature wear and tear. It has to raise into the door seal to form a tight bond to prevent excess cabin noise.

The feature has nothing to do with security. A thief will either cut the door seal or just break your window.
Everyone is getting close but not quite there.

This started in high end cars with frameless windows. Originally frameless windows had only a pressure fit to seal the window against the rubber seal (the seal would only be on one side of the window). This did not work that well as the pressure fit was never perfect resulting in noise and potentially leaks, at high speed these windows tended to lift from the seal resulting in lots of noise. The better solution was to use the two sided rubber seal in framed windows, but the only way to do this was to lower the window a bit when it was opened and closed.
Appreciate 0
      04-17-2008, 11:10 AM   #29
mkaresh
Second Lieutenant
18
Rep
267
Posts

Drives: 2000 Lexus GS 400
Join Date: Jan 2007
Location: Michigan

iTrader: (0)

The last post finally got it. To put it a little more clearly, it's so you can have a seal that wraps all the way around the glass with frameless glass, forming an inverted U, just as you always have with framed glass. The older, cruder design is prone to air leaks and windnoise, and is much harder to properly adjust.

It has nothing to do with air pressure in the cabin, or they'd do the same with framed windows.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 09:40 AM.




f30post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST