Why do higher end BMW's lower windows when doors are opened?

wj4 · 03-02-2008, 01:53 AM

I've always wondered about this feature. It's not limited to BMWs, but other more expensive cars as well. When you open the door, the window lowers a little, then it raises up when the door is closed.

What's the purpose of this feature?

RRGOO7 · 03-02-2008, 01:57 AM

usually done on coupes to help seal the cabin more

cooldude · 03-02-2008, 02:03 AM

The cars which donot have the window housing like the sedans usually do.
e.g. mid 90's lexus es, acura tl, etc when the door is closed the window takes the pressure so the window is lowered so that the window is saved from pressure

wj4 · 03-02-2008, 02:04 AM

Quote:

Originally Posted by RRGOO7

usually done on coupes to help seal the cabin more

I don't get how it would help seal the cabin more if the windows lower when the doors open as oppose to being closed at all time.

wj4 · 03-02-2008, 02:07 AM

Quote:

Originally Posted by cooldude

The cars which donot have the window housing like the sedans usually do.
e.g. mid 90's lexus es, acura tl, etc when the door is closed the window takes the pressure so the window is lowered so that the window is saved from pressure

This actually makes some sense, so this feature is to reduce the stress put on the windows. Thanks.

e92phreak · 03-02-2008, 02:44 AM

I found out the hard way. For some ODD reason, when closing my door, the window wasn't lowered... I think it raised itself... I probably hit my keyfob or something... Anyways, it wasn't lowered, and when I closed the door, it make a noise almost like something riccochet'd off my window.

GAMEgates · 03-02-2008, 02:51 AM

like rrg007 said its mostly done on coupes or 2drs mainly because the windows are large and isnt shrouded at the top by metal. Its bare glass. So in order for it to close it must lower a little to pass through the arch.

jjbirch · 03-02-2008, 04:52 AM

mostely coupes and soft tops as they are frame less windows just glass the glass does look mre stronger than the normal window

OBI_agent · 03-02-2008, 05:08 AM

Yeh.....I have seen the window lower in a corvette too....sounds cool when its done...lol

pokerface · 03-02-2008, 10:28 AM

easier to shut the doors as it relieves a bit of air pressure

TheAcAvenger · 03-02-2008, 11:14 AM

Im not sure its really related to more expensive cars.... the mustang GT does the same thing.

e90driver · 03-03-2008, 09:06 AM

Does the 3er coupe do this also? I should have paid more attention when I test drove it.

sinnet112 · 03-03-2008, 11:48 AM

Yep, just on coupes and convertibles. First time I experienced this was on a 350Z back in '03

nmulax · 03-03-2008, 12:18 PM

Quote:

Originally Posted by e90driver

Does the 3er coupe do this also? I should have paid more attention when I test drove it.

yes it does

c0nstant · 03-03-2008, 09:49 PM

as others have said, its because the weather stripping is not connected to the tops of the windows as opposed to on sedans. the closing action simply ensures a snug fit under the stripping. and as far as having that feature on higher end makes and models, my 97 328is does it every time

edit: plus coupe windows are generally a lot bigger than those on sedans, idk what thats has to do with anything. just throwing it out lol

shift330 · 03-04-2008, 12:03 AM

My G37 does it too. My old G35 did it but my 04 Mustang GT didn't so that must be something that domestics switched over to later on

leftcoastman · 03-04-2008, 01:13 AM

And it helps prevent from compressing the air in the cabin......reducing the stress on your eardrums.

I'm serious. Get in an older car, slam the door and note the effect on your ears.

Couch · 03-04-2008, 10:09 AM

This really does go back a ways. My friends '91 or '92 Integra did this.

shragon · 03-04-2008, 07:53 PM

it's done on coupes. i know for bmw, this at least dates back to the e36.

johnL · 03-05-2008, 03:00 AM

Like someone else already mentioned, this only occurs for frameless doors. It's not really a thing restricted to more expensive cars.

montreal red · 03-12-2008, 11:31 PM

think a lot of cabrios and coupes have this feature... its not very uncommon... it's a great idea to solve an old problem.

boymonkey · 03-14-2008, 07:34 PM

I have a two-door which doesn't have this feature, and when someone slams the door or the trunk while I'm in the car, I can feel the air pressure on my ear drums. I think that's one reason for the feature. Another is that it takes a bit more to close the trunk (mine's connected to the cabin, like a hatchback), because of the air getting compressed. I have to push it all the way down until it latches.

03-02-2008, 01:53 AM	#1
wj4 Major General 356 Rep 7,719 Posts Drives: E90 manual 335i Join Date: Nov 2006 Location: Burbank, CA iTrader: (8)	Why do higher end BMW's lower windows when doors are opened? I've always wondered about this feature. It's not limited to BMWs, but other more expensive cars as well. When you open the door, the window lowers a little, then it raises up when the door is closed. What's the purpose of this feature?
	Appreciate 0 Tweet Quote

03-02-2008, 01:57 AM	#2
RRGOO7 Colonel 376 Rep 2,451 Posts Drives: GTR Join Date: Dec 2006 Location: Miami FL iTrader: (13)	usually done on coupes to help seal the cabin more
	Appreciate 0 Quote

03-02-2008, 02:03 AM	#3
cooldude Lieutenant 27 Rep 518 Posts Drives: Bmw 335i Join Date: Mar 2008 Location: Charlotte iTrader: (0)	The cars which donot have the window housing like the sedans usually do. e.g. mid 90's lexus es, acura tl, etc when the door is closed the window takes the pressure so the window is lowered so that the window is saved from pressure
	Appreciate 0 Quote

03-02-2008, 02:44 AM	#6
e92phreak General 392 Rep 21,745 Posts Drives: E92 335i TiAg/E46 323i TiAg Join Date: Mar 2007 Location: CA iTrader: (1) Garage List 2007 E92 335i [9.50] 2000 E46 323i [0.00]	I found out the hard way. For some ODD reason, when closing my door, the window wasn't lowered... I think it raised itself... I probably hit my keyfob or something... Anyways, it wasn't lowered, and when I closed the door, it make a noise almost like something riccochet'd off my window. __________________ 07 E92 335i \| TiAg \| Step \| Padl \| Cmft \| Alum Trm \| PDC \| Nav \| Assist \| Sat \| Lthr \| Prem \| Sprt \| Rear Splr \| RDSport Quads \| iPod \| V1 \| LT Refl \| VS Clear Bra \| OEM Lip \| KWV2 \| Mtec Sides \| BBS LM-R 00 E46 323i \| TiAg \| 5sp \| Sport \| Roof \| RDSport Cams \| RDSport tune \| RDSport Shift \| Volk LE37 \| M3 spoiler \| PSS9 \| SuperSprint \| Brembo
	Appreciate 0 Quote

03-02-2008, 02:51 AM	#7
GAMEgates Second Lieutenant 35 Rep 216 Posts Drives: SpaceGray e92 335 Join Date: Nov 2005 Location: Palm Springs, CA iTrader: (0)	like rrg007 said its mostly done on coupes or 2drs mainly because the windows are large and isnt shrouded at the top by metal. Its bare glass. So in order for it to close it must lower a little to pass through the arch. __________________
	Appreciate 0 Quote

03-02-2008, 04:52 AM	#8
jjbirch Banned 79 Rep 2,927 Posts Drives: E60 530D M SPORT Join Date: Feb 2006 Location: england iTrader: (0) Garage List 2006 320d m sport [0.00]	mostely coupes and soft tops as they are frame less windows just glass the glass does look mre stronger than the normal window
	Appreciate 0 Quote

03-02-2008, 05:08 AM	#9
OBI_agent D to the X to the B! 357 Rep 2,106 Posts Drives: ABS,American bargain supercar Join Date: Jul 2007 Location: Dubai iTrader: (0)	Yeh.....I have seen the window lower in a corvette too....sounds cool when its done...lol
	Appreciate 0 Quote

03-02-2008, 10:28 AM	#10
pokerface Colonel 443 Rep 2,531 Posts Drives: F25 X3 N20 / F80 ZCP Join Date: Apr 2006 Location: Toronto iTrader: (1)	easier to shut the doors as it relieves a bit of air pressure
	Appreciate 0 Quote

03-02-2008, 11:14 AM	#11
TheAcAvenger Brigadier General 137 Rep 3,132 Posts Drives: 2018 R35 GTR / 2007 E92 335i Join Date: Apr 2006 Location: 757 > Nova > Denver iTrader: (1)	Im not sure its really related to more expensive cars.... the mustang GT does the same thing. __________________ 2018 R35 GT-R Cicio800 \| 2007 E92 335i - RB Turbos, TC Kline DA Coils, HPA M3 Suspension, Quaife LSD, Stoptech BBK, JB4, FuelIT, AR Downpipes, RDSport Quads, Stett OC, Helix IC, Volk TE-37, Vorsteiner V-35, OSS Headlights \| Retired - 2015 F82 M4
	Appreciate 0 Quote

03-03-2008, 09:06 AM	#12
e90driver Lieutenant 14 Rep 502 Posts Drives: 06 325i, 08 328xi Join Date: Sep 2005 Location: Michigan iTrader: (0)	Does the 3er coupe do this also? I should have paid more attention when I test drove it. __________________ see ya 06 325i. IT'S HERE!- 08 E92 328xi, Premium, Auto, Cold- Montego Blue
	Appreciate 0 Quote

03-03-2008, 11:48 AM	#13
sinnet112 Major 31 Rep 1,118 Posts Drives: 2009 E89 Z4 Join Date: Dec 2006 Location: NJ iTrader: (1) Garage List 2007 335i Coupe [0.00] 2007 328xi Sedan [0.00]	Yep, just on coupes and convertibles. First time I experienced this was on a 350Z back in '03 __________________ Z4 sdrive30i \| Deep Sea Blue \| Ivory White Nappa Extended Leather \| ZSP
	Appreciate 0 Quote

03-03-2008, 09:49 PM	#15
c0nstant Lieutenant General 1830 Rep 17,322 Posts Drives: G80 M3 Join Date: Apr 2007 Location: Los Angeles iTrader: (1)	as others have said, its because the weather stripping is not connected to the tops of the windows as opposed to on sedans. the closing action simply ensures a snug fit under the stripping. and as far as having that feature on higher end makes and models, my 97 328is does it every time edit: plus coupe windows are generally a lot bigger than those on sedans, idk what thats has to do with anything. just throwing it out lol
	Appreciate 0 Quote

03-04-2008, 12:03 AM	#16
shift330 Blue Force Tracker 129 Rep 1,372 Posts Drives: 2010 Hyundai Genesis Coupe Join Date: Feb 2008 Location: Sierra Vista, AZ iTrader: (6) Garage List 2006 330i [0.00]	My G37 does it too. My old G35 did it but my 04 Mustang GT didn't so that must be something that domestics switched over to later on __________________ Stay safe 855th MP Company! Hosmer/Espinoza you're my boys!!
	Appreciate 0 Quote

03-04-2008, 01:13 AM	#17
leftcoastman Lieutenant Colonel 55 Rep 1,714 Posts Drives: 335i Join Date: Jan 2007 Location: Near some canyons iTrader: (1)	And it helps prevent from compressing the air in the cabin......reducing the stress on your eardrums. I'm serious. Get in an older car, slam the door and note the effect on your ears.
	Appreciate 0 Quote

03-04-2008, 10:09 AM	#18
Couch Colonel 146 Rep 2,900 Posts Drives: E92 335i Join Date: Jan 2007 Location: Houston iTrader: (0) Garage List 2007 E92 335i [0.00]	This really does go back a ways. My friends '91 or '92 Integra did this.
	Appreciate 0 Quote

03-04-2008, 07:53 PM	#19
shragon Moderator 511 Rep 27,440 Posts Drives: BMW Join Date: Oct 2005 Location: Bay Area, CA iTrader: (7)	it's done on coupes. i know for bmw, this at least dates back to the e36. __________________ www.cardomain.com/id/shragon
	Appreciate 0 Quote

03-05-2008, 03:00 AM	#20
johnL Second Lieutenant 8 Rep 288 Posts Drives: e46 M3 Join Date: Jan 2008 Location: Bay Area iTrader: (0)	Like someone else already mentioned, this only occurs for frameless doors. It's not really a thing restricted to more expensive cars.
	Appreciate 0 Quote

03-12-2008, 11:31 PM	#21
montreal red chris 291 Rep 12,142 Posts Drives: White Boat Join Date: Jun 2007 Location: Toronto iTrader: (31)	think a lot of cabrios and coupes have this feature... its not very uncommon... it's a great idea to solve an old problem. __________________ Current: 2013 F10 M5 & 2016 Mini JCW 2013 GLK350 (gone), 997.1 GT3RS (gone), 2009 WRX STI (gone), e92 M3 (gone)
	Appreciate 0 Quote

03-14-2008, 07:34 PM	#22
boymonkey Lieutenant 41 Rep 530 Posts Drives: slow Join Date: Apr 2007 Location: Canada iTrader: (0)	I have a two-door which doesn't have this feature, and when someone slams the door or the trunk while I'm in the car, I can feel the air pressure on my ear drums. I think that's one reason for the feature. Another is that it takes a bit more to close the trunk (mine's connected to the cabin, like a hatchback), because of the air getting compressed. I have to push it all the way down until it latches.
	Appreciate 0 Quote