TJEli

Why does it do this? Rolls up a little when the door is opened and goes back down when the door is closed.

-Eli

kostas_os

I am guessing that it stops when it encounters a certain resistance from the rubber insulation around the door when the door is closed, and it fully opens when the door is open, to ensure a tight seal even if the rubber wears down a little?

TJEli

Nope. That’s not it. It rolls up just a little when you open the door and goes back down when closed.

-Eli

prashanth1337

I don't know exactly why, but you will see this with any car that has frameless windows

LOVEMYGOLFR

Its so that the window can slide up BETWEEN the rubber seal when the door is closed again- I have had 3 BMWs with frameless windows and on an older E46 model (LOVE the E46 BMW- that WAS the ultimate driving machine) I had a drivers window motor that was half malfunctioning- would go up and down but not the little "bump" when the door opened. That meant I had to shut the car- open the passenger door and I had to lean in and using the power window switch drop the drivers window an inch then engage the switch again to roll the window back up in between the seal- pain the ***. I was getting rid of the car but the motor, while it worked on full up and down, had to be replaced since it didnt do that "bump"- $ 1100 - no thank you.

TJEli

Thanks for the reply’s guys. I know when the windows go down a little when opened and back up when shut for the door seals. This is different. If the windows are down. (All the way) and you open the door the window the roll UP about an inch and stay that way while it’s open. When the door is shut it will roll back down all the way.

-Eli

ArvX147

Maybe it has something to do with isolating the glass from the vibration of closing the door? It's the only functional reason I can think of.

superswiss

I've never found confirmation on this, but I believe it's so that you have something to hold on since there are no window frames that you can use to shut the door. It's easier to grip the glass than the door handle or the bulky door to for example stop it from banging into the car next to you. Another thing I've heard is to keep the glass from braking when you slam the door. With it sticking up it's more stable.

HudsonS5

Yes it is a design feature to prevent the window from rattling inside the door when the door is shut. It was mentioned in a review I saw.

carkarl

My guess is that this is to relieve stress on the door internals when you slam the door. If you have ever removed a door card, such as to upgrade audio speakers, you'll notice the window retraction system is a pretty flimsy looking track inside the door, often with plastic guides. If the glass were fully retracted inside the door, only the very edge is still in the slotted weather stripping of the door. With enough cycles slamming the door, I could easily see those internal guides flexing and the window glass slipping out of alignment with the slot in the door. Then you'd have a real mess with a window that won't go up or perhaps a door full of glass shards.

On the bright side, seeing and hearing the window poke out of the door might remind you that you are parking with it open and not just having really clean windows!