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Discussion Starter · #1 ·
The wind noise from the deflector is eliminated if it is held down in its resting position, and this does not seem to cause any downdrafts or buffeting, at least up to 65mph.

The obvious question is, if this is true, why have a wind deflector at all? Second question: is there a simple way to prevent the deflector from deploying? Duct tape always works, but a more elegant solution would be preferred.
 

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Discussion Starter · #3 ·
They seem to have designed the wind deflector without much planning. It's basically a metal screen (similar to an ordinary house window screen) supported in a frame. It seems predictable to me that high velocity air traveling through the small screen openings would create a racket.

Perhaps they devoted their engineering euros to other areas of the vehicle, and threw in the wind deflector as an afterthought. Disappointing, but I guess I'll pull out the trusty duct tape and enjoy the otherwise excellent driving experience.
 

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Rob V said:
I know what you mean. I've done this with my current car and have noticed a difference. Except, in my car it changes the noise but doesn't really reduce the noise.
Don't have my X3 yet, but I've noticed the same thing in other cars I've owned. Holding the screen changes the noise from high frequency to low frequency, but doesn't really change the magnitude. Personally, I find the low frequency more disturbing.
 

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Discussion Starter · #5 ·
On my X3, holding down the deflector doesn't only change the frequency of the sound; it eliminates it. Most of the noise seems to come from the air rushing through the screen, so taking the screen out of the airflow removes the problem.

I expected to get some buffeting and downdrafts, but experienced neither. Nor did my daughter, who was sitting in the back seat. I only tried this once, today, which was a relatively windless day, so I'll have to try it again in different conditions.
 

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Since we had some nice weather lately, here's what I found out.

With the roof open to the first position (first open position, not the tilt) and the windows down, it was noisy, VERY noisy. Even at < 40mph, the wind noise was annoying. Then last night I tried it with the roof ALL the way open, and the windows down - it was FINE! Up to about 60. Go figure.


--Randy
 

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Discussion Starter · #10 ·
rrinker said:
Since we had some nice weather lately, here's what I found out.

With the roof open to the first position (first open position, not the tilt) and the windows down, it was noisy, VERY noisy. Even at < 40mph, the wind noise was annoying. Then last night I tried it with the roof ALL the way open, and the windows down - it was FINE! Up to about 60. Go figure.

--Randy
I'll have to try the roof all the way open with the windows down. Sounds like a good option for a beautiful sunny day.

The experience I reported was with the windows up and the moonroof open to the first position, which worked well with the deflector held down. Windows up with the moonroof all the way open didn't work very well: too much buffeting.
 

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Though I have a 3-series and not an X3 I have played with the wind deflector a bit. I found that at < 20MPH (believe it or not) the buffeting can be so bad it is almost painful while holding the deflector down. The rapid increase/decrease in cabin preasure was very unpleasant on the ears. It almost feels like a huge subwoofer is pounding out a stacato at about 200 BPM at very low frequency. Above a certain speed the wind is flying over the root fast enough that it probably doesn't interact with the deflector much anyway.

YMMV.

James.
 

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I have a different sort of problem with my roof on my X3...over 65mph the deflector goes down, but then there is a terrible rattling noise comming from the glass...it sounds like 2 panes of glass hitting against eachother. I brought it to the dealer and they looked at it and said they couldn't replicate the problem, but the "tightened" everything. The problem still occurs. Did this happen to anyone else if so how did u fix it...PS sorry if i hijack the thread.
 

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Discussion Starter · #13 ·
tompal said:
I have a different sort of problem with my roof on my X3...over 65mph the deflector goes down, but then there is a terrible rattling noise comming from the glass...it sounds like 2 panes of glass hitting against eachother. I brought it to the dealer and they looked at it and said they couldn't replicate the problem, but the "tightened" everything. The problem still occurs. Did this happen to anyone else if so how did u fix it...PS sorry if i hijack the thread.
I've heard of this problem too, although I haven't experienced it. Here's a post I copied from another site that may help you:

"After having eliminated 90% of the wind noise with installing the BMW Wind Deflector (quiet enough now at "position #1" to hear the soon to be replaced door seals creak)all I was experiencing was a rattle of the roof over 55mph. I also experienced the same rattle when closing the door of the car with the roof open and when going over sharp bumps.

I noticed the rear edge of the rear window element of the roof rattling against the plastic tray that goes the width of the car beneath the window. Tilt the window up and you can see this tray. You might even be able to see scuff marks in the 'dust' in the tray where contact is being made. I simply placed a small and very thin piece of compressible foam (from a foam brush) at the centerline of the car on top of the tray and tilted the window down to see what would happen. No more rattle when the window is slide back to position one and the car is driven up to 85mph (I will not go faster). The tray does not distort downward when the window is tilted down also. I will place a self adhesive piece of black velcro (the fluffy side)to replace the foam before I tilt the window again while moving. I see this same material used elsewhere in the pano roof."
 
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