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-   -   The two lil flaps right in front of the front tires (http://www.bimmerfest.com/forums/showthread.php?t=527234)

0428 03-16-2011 07:52 AM

The two lil flaps right in front of the front tires
 
Does anyone know what they are for?

Bruin72 03-16-2011 12:40 PM

I hope you get an answer since I'd like to know as well. I already broke one of mine off on ice over a parking lot curb..

soldmystang 03-16-2011 04:59 PM

aero baby, aero............ good for at least .0365987 / mpg

Penguin 03-16-2011 08:42 PM

Anyone have a picture? I don't seen to have them, but I see three clipnuts on both sides with nothing mounted on them in that area.

GiaGiaJa 03-16-2011 08:56 PM

Subscribed... I have them on my 328i as well. I assume they are mud guards? :dunno:

ANZAC_1915 03-16-2011 10:33 PM

Quote:

Originally Posted by soldmystang (Post 5923502)
aero baby, aero............ good for at least .0365987 / mpg

yep, wind deflectors. Very common these days.

Kzang 03-17-2011 10:30 AM

Quote:

Originally Posted by GiaGiaJa (Post 5924031)
Subscribed... I have them on my 328i as well. I assume they are mud guards? :dunno:

LOL Mud guards would be on the back side of the wheels... look at your own car in your signature.. see the little flaps in front of the wheels? That is used to deflect wind.

Kzang 03-17-2011 10:36 AM

1 Attachment(s)
Hard to tell in this picture, but you can see the flap I circled.

0428 03-17-2011 10:37 AM

Quote:

Originally Posted by ANZAC_1915 (Post 5924233)
yep, wind deflectors. Very common these days.

The only answer it seems would be aero......... but, I am not so sure about those two lil things having any sort of affect on the aerodynamics of such a large SAV.

Marlbro 03-18-2011 05:21 AM

Quote:

Originally Posted by ANZAC_1915 (Post 5924233)
yep, wind deflectors. Very common these days.

As a vehicle Designer, & Engineer I can tell you for 1000% that they are there for Areo reasons.
They are extensions of the wheel arch liners, and are on every X5 & X6, and most Fords :thumbup:
by guiding air around your "tires" they also have some noise damping affect too (minimal)
as an aero aid they help very slightly towards fuel economy too.
These are wind tunnel tested, and developed.
Having said that, if you were to cut them off, you probably wouldn't notice the difference.

0428 03-18-2011 08:12 AM

Quote:

Originally Posted by Marlbro (Post 5927206)
As a vehicle Designer, & Engineer I can tell you for 1000% that they are there for Areo reasons.
They are extensions of the wheel arch liners, and are on every X5 & X6, and most Fords :thumbup:
by guiding air around your "tires" they also have some noise damping affect too (minimal)
as an aero aid they help very slightly towards fuel economy too.
These are wind tunnel tested, and developed.
Having said that, if you were to cut them off, you probably wouldn't notice the difference.

I believe you. But also I believe "if you were to cut them off, you probably wouldn't notice the difference". Then so what's the point? :confused:

In racing, where every little bit counts, why dont you see these flaps on race cars, or high end car like Lambos or Astons?

diesaroo 03-18-2011 10:08 AM

Quote:

Originally Posted by 0428 (Post 5927561)
I believe you. But also I believe "if you were to cut them off, you probably wouldn't notice the difference". Then so what's the point? :confused:

In racing, where every little bit counts, why dont you see these flaps on race cars, or high end car like Lambos or Astons?

If in fact this is true, it might be because they're so low to the ground anyway, most of the airflow is going over the car producing downforce that they're not as concerned with drag under the car:dunno:

Penguin 03-18-2011 01:07 PM

Quote:

Originally Posted by Marlbro (Post 5927206)
They are extensions of the wheel arch liners, and are on every X5 & X6, and most Fords :thumbup:.

Well, FWIW, they aren't on my US 2010 X5 diesel.

soldmystang 03-19-2011 08:45 PM

Quote:

Originally Posted by 0428 (Post 5927561)
I believe you. But also I believe "if you were to cut them off, you probably wouldn't notice the difference". Then so what's the point? :confused:

In racing, where every little bit counts, why dont you see these flaps on race cars, or high end car like Lambos or Astons?

really? you think the reason BMW puts these plastic bits on their SAVs is because of the racing heritage of the marque? :confused:

CAFE Standards being what they are these days even the most miniscule reduction in drag is a win-win for BMW.

i won't swear to it Penguin but your 35d might be exempt from CAFE.

Marlbro 03-21-2011 03:57 AM

Quote:

Originally Posted by 0428 (Post 5927561)
I believe you. But also I believe "if you were to cut them off, you probably wouldn't notice the difference". Then so what's the point? :confused:

In racing, where every little bit counts, why dont you see these flaps on race cars, or high end car like Lambos or Astons?

Well, as I said, they are developed in wind Tunnels, and as with all "Labratory" developments
you can show minor gains here and there, and convince people that they are worth it.

BMW prouds itself on having developed the "Air cushion" it calls it.
I was reading in last months BMW magazine (the one with the new X3 on it)
how by developing the outer body styling, that feature line that runs from the front wheel arch, rearwards, and blends out towards the rear. By developing air flow around the front end, past the tyres, they can build up this "Air cushion" that helps to clean up air flow past the car, and in so doing so also help fuel economy.

Now all that might be true in an Air Tunnel, but in choppy cross winds driving past trees, and trucks on the high way, I doubt how much affect that would really have.

racing cars are a whole different kettle of fish, Much lower to the ground, the front Spoiler splitter (that flat piece) sticking out of the front Spoiler is there to "Split" air flow, and push most of it over the car, producing down force. the negative air flow under a very low car, with a flat bottom, will create a partial vacuum, sucking the car down. (at high speeds)

Why don't we have that on road cars,
well, how would you get over those speeds bumps in the Sears car park ?

Most lambos, Aston martins, and Ferraris, have front spoiler splitters, and an under tray with aVentury duct in it that exits at the rear, and usually, tey put the exhuast there too.
This has the affect of accelerating the air under the car, creating more down force, and as it exits, helps to suck the gases out of the exhaust.

Now as to the OP that said his X5 doesn't have these front flaps.
All Euro X5 & X6s I've sen have them, and also a lot of Euro cars have them.
But i did look at one used X6, when choosing my X5 where the last owner had broken one off.
How he did that I don't know (maybe off roading)

quackbury 03-21-2011 11:34 AM

I think the easiest way to break them off is to pull in over a curb (that would be "kerb" to Marlbro). Hitting a racoon, skunk or opposum at speed would also do the trick.

BMW probably had to decontent the X5 in some other areas to pay for these little doo-dads. Think of them as foreskins for your wheels.

Marlbro 03-22-2011 05:39 AM

Front wheel forskins.....That's funny :rofl::rofl:

but as I said, would you really mis them......
I don't think I would go to those extreams to knock them off, but I think any of those would do it.


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