[Timpo]

why do cars have this flat surface around the fender?

http://i.ytimg.com/vi/zfyLZbC-yJQ/maxresdefault.jpg
http://carsorder.com/images/lamborghini-aventador-on-top-of-its-competition5.jpg
http://i.kinja-img.com/gawker-media/image/upload/s--h0shZTvZ--/c_fit,fl_progressive,q_80,w_636/y8ceyrukxx27g7axa1mw.jpg

but as you can see, some cars don't have that flat surface around the fender
http://www.ealuxe.com/wp-content/uploads/2015/06/Koenigsegg-One-1-Powerful-Production-Car-4.jpg
http://www.kidston.com/images/cars/77_1.jpg

[Reeyal]

Probably just by design. It gives the car a flush to wheel look.

[vitaminG]

It's for aero

[underscore]

I don't know what it's for but I absolutely hate it.

[smoothie.]

I used to think it was for rigidity, but that's probably wrong.

[jasonturbo]

It's most often for rigidity, just ask anyone who has ever cut the inner lip out of a fender, shit gets wobbly.

You'll probably notice that non-metallic body panels will often lack the feature of a flat edge on a wheel arch or an inner lip.

Though I'm sure certain vehicles have it for aero reasons as well.

And Timpo, what gives? No GTR pics?

[dared3vil0]

Interesting... I never noticed that til you mentioned it, but yikes.

I would suspect it's to make the OEM wheels look flush and "square" with the fender.

[320icar]

Rigidity for sure. When I cut my miata fenders for wide body they became like a wet noodle

[cunninglinguist]

There was an article in the Province that mentioned it was for aero.

[kouki_monster]

There was an article in the Province that mentioned it was for aero.

The Province was writing about flat surfaces on car fenders? o_o

[Berzerker]

Rigidity and also for giving something for the inner fender liners and such to adhere to.

I would like to see wind tunnel testing showing how a small flat surface affects aero.

Berz out.

[Lomac]

Definitely rigidity. Thin gauge metal gets flimsy without proper support. With CF, however, it probably has to do with aero. Pretty sure carbon fibre is strong enough on it's own that it doesn't need structural support in those designs.

[E-SPEC]

I think a more important question is why does a man have an very unmanly avatar?

[cunninglinguist]

The Province was writing about flat surfaces on car fenders? o_o

There was an article in the Province newspaper mentioning some trends that should go away. I can't find it online at the Province.com but it is this article exactly from Jalopnik because I remember the picture of the Honda at #10.

Ten Car Trends That Need To Die (http://jalopnik.com/ten-car-trends-that-need-to-die-1702535593)

[xjc11]

So that they can put a widebody kit in

[twitchyzero]

is there a functional purpose to covering the wheel wells? It can't be for aerodynamics?

http://upload.wikimedia.org/wikipedia/commons/1/1b/Honda_Insight_Back.JPG
https://upload.wikimedia.org/wikipedia/commons/5/53/Chevrolet_Caprice_wagon.jpg

[Mike.L]

It's main purpose is for aerodynamics against road debris and redirection of air flow.

Think of a sedan vs van, a sedan pulls air into it at the rear windshield.



http://www.futurecars.com/images/Ford-wind-tunnel.jpg

http://wardsauto.com/site-files/wardsauto.com/files/imagecache/large_img/uploads/2013/04/mercedes-cla-wind-tunnel.jpg

[underscore]

is there a functional purpose to covering the wheel wells? It can't be for aerodynamics?

It is actually for aero, although on some cars it was for cosmetics.

[BoostedBB6]

Reason for this on high end performance cars is to reduce or get rid of boundary layer separation (causing increase in vehicle drag).

You will find that vehicles designed with smooth front ends are often times not using this style of fender edge because they do not need to. They can retain the smooth shape and have little to no separation. With vehicles that use a lot of front aero or have a very angular front end will benefit from this to reduce the separation of flow over the body.

Why it is used on most all new cars......because others started using it and it became something of a stylized thing to copy that high end cars are using.