Why can't the BRZ GT300 or factory BRZ wheels have flush fitment?
 

http://www.ft86club.com/wallpapers//brz300/IMG_5966.JPG

http://star-motoring.com/getattachme...ta-86.jpg.aspx


Prius GT300
http://as-web.jp/photo/pnews/201201/25374/01.jpg


Yet VWs like the Golf R have wheels that come more flush from the factory.
http://cache.jalopnik.com/assets/ima...Golf_R-TOP.jpg


And LFA fitment is not bad.
http://myautowants.com/wp-content/up.../lexuslfa5.jpg

What are the reasons for this? :iono:

its probably a result of digging through the parts bin. with the gt, i just assume they didnt care too much as being flush isnt any faster

Because race car.

I would think it's a critical area of the car to engineer. Logic tells me it might have to do with brake cooling and ventilation. Front brakes typically experience greater load than the rears and the wheels on the Prius look more sunken in up front (unless the angle is throwing me off). But I'd like to hear what someone knowledgeable in the area has to say.

Becos tyres have drag and on a race car function > form

All cars are like this.......

Most if not all German cars are more flush with the fenders while every other make is not.

Ive come to expect it being some kind of German thing with their cars.

I'd think the smaller the gap between the wheel and bodywork the less drag :iono:

See LFA. Hypermilers use plastic wheel well gap covers to close the gaps.

^Actually, I can see drag being caused by the tire on the VW in the area I circled below but that's due to the body curving inward.

But I agree there would be less air turbulence if wheels were more flush or, in this case, if the body were more flush with the wheels.

i dont think its that critical. i mean we complain when we cant stick huge rims under the wells and now we are complaining that there is a gap
what do you mean gap covers?
i think the majority of the drag comes from the top of the tires since they are spinning in the opposite direction. there shouldnt be too much drag at the bottom as the tire is moving at the same speed as the air going past it. the top of the tire is dealing with twice the wind speeds in relation to the speed of the car

So kinda like a fender extension that goes into the wheel well...but mainly used on cars with a huge gap like trucks.

I think the tires spinning doesn't have that great of an effect, usually boundary layer thickness is cited as 1 inch or something. Not much air makes it to the top of the tire anyways. I believe most of the drag is caused by the very bottom of the tire, where air is getting "squished" out to the sides against the ground by the tire. Not sure why this is an exceptionally large source of drag but it seems to be. This is what wheel spoilers you see on all cars are for, directing the air away from the bottom front area of the tire saves more drag than it costs, and reduces lift more than it causes by damming up air before it against the underbody. The sides of the tire doesn't cause much drag as they're smooth, the rims cause a bit of drag though which is why the Insight for example has smooth rim surfaces and the rear wheel covered.

switchlanez you're right about the body curving in, it exposes the edge of the tire to the airflow.

I don't know how close the wheels should be when the slight pumping action of the spinning wheel and the effects of the rims are taken into account, but the LFA is probably a good reference as they paid quite a bit of attention to this sort of stuff.

being flush is not all fun n games ... it looks nice ...
but I went from Sorta-flush to NOT .. because it was hurting
my car ... I have fenders rolled with ET37 BBS VZ... and I rub-a-dub.

With the BRZ ... I rather stay stock ... suspension travel is a great thing...
for example I did not realize how much better my current vehicle handled
a corner untill I raised the coils up an inch or two from my Sortaflush stance.

I don't think this car will have as many fitment issues. ;)

Better question. Who Cares?

kind of a stupid question considering that its safe to say that at least the op cares

Despite the car looking great it has been designed to DRIVE and handle well, "flush" fitment is quite good at ruining the handling and driving feel in favor of looks. I'm glad they haven't sacrificed the control and feeling (what this car is about) just so it can look more "trendy"

You want to do that kind of thing to yours? Go for it, slap some 22"s on there while you're at it, I'm all for personal modifications to get a car to be what you want it to be.

Put me down in the camp who doesn't understand the flush fitment craze. I would complain about understeer long before I mentioned how much space there is between the top of the wheel and the bottom of the wheel well.

Anyway it's a balance between practicality and performance. The car sits pretty low already (lower then a Golf R) and any lower scrapping on driveways/speed bumps might be a concern.

gasp

http://fotos.autozeitung.de/462x347/...TM-2012-07.jpg

It's not flush, and its german!

No offense to the OP but the cars that way because its functional. Very few cars come out from the factory "flush". If you want it flush mod the car to your hearts content. But as for getting that stock, don't expect it.

being flush has no impact on handling. there are often sacrifices made to attain a flush fittment but where the wheel sits in relation to the plane of the fender doesnt influence handling

Making flush your self can make WORSE handling I the car wasn't designed for the show pony setup in the 1st place. It creates more drag than sunken (spokes make drag as well) and it takes more effort to design from factory to sit flush when level, but sink when squat.
Hellaflush->hellashit

being flush from the factory doesn't affect handling, however it effects aerodynamics and MPG. Which is why you won't see it from many manufacturers, or race cars.

^

LFA? :iono:
http://myautowants.com/wp-content/up.../lexuslfa5.jpg

Cayman R? :iono:
http://www.blogcdn.com/uk.autoblog.c...cayman-r-3.jpg

Veyron? :iono:
http://farm3.staticflickr.com/2764/4...c5129dc5_z.jpg

Yeah, when I saw the BRZ in person I hated two things about it in stock form.

1. Wheels gap is nasty looking
2. The wheels are too sunken in and looked like it needed 15F/20R mm spacers

I'm hearing a lot of assertions from you guys with no technical facts to back it and many are confusing flush with hellaflush. I don't care about hellaflush nor did I ever mention it. But I do care about how my car looks (is it wrong to want that particularly out of a sports car?) I don't understand why a manufacturer decides to push a wheel so far into the fender when they have the choice not to from the onset of development.

When I upgraded to C-ONE (a Toyota tuning arm) WedsSport wheels designed exclusively for the Celica, it looked and handled more beautifully compared to stock. This was years ago when I'd never heard of hellaflush. I didn't even understand the concept of offset when I bought the wheels. It wasn't til after I installed them that I noticed they stuck out a little more. I remember googling "wheel offset" and finding out these stuck out a subtle 13mm or so compared to stock. That's where my discerning eye started for fitment (again, no hellaflush craze existed at the time). Even the TRD Celica wheels stuck out around 10mm compared to stock. I don't understand what's so hard about making it come like that from the factory.

http://www.newcelica.org/photopost/d...22115327_l.jpg

https://fbcdn-sphotos-a.akamaihd.net...891_4714_n.jpg

that's just a side effect of fitting very wide wheels on those cars. In their case more grip > less aerodynamic drag. Because it is a minimal difference. However on race cars where every bit matters. They always want the wheels tucked in for less drag down the straight aways.

http://2.bp.blogspot.com/_FoXyvaPSnV..._3559_fine.JPG


http://www.7extrememotorsports.com/l...tte-c6r-02.jpg

Why someone would care so much about a minute detail bets me.

To elaborate I think it's like that for many reason. The wheels are pretty skinny from the factory stock. The designers made the wheel well large so it can easily accommodate larger fitment. Also a beneficial by product is reduced drag on the car so better mileage on the highway. All these add up to why the car comes in that set up.

^Manufacturers can design wheels with a more positive offset so they remain sunken in (in agreement with your aerodynamics argument) and maintain wheel width for handling. I don't see why they didn't do that with the LFA, Golf R, Veyron, Cayman R, etc.

And fitment may be a minute detail but is also an acquired taste. Why are there fine wines v. cheap wines? Most people don't understand the difference but it's there and important to those who do. It's particularly ridiculous when you have fender bulges that flare out and come pre-rolled from the factory but there's still a huge gap and the wheels are sunken in (e.g. BRZ).

http://star-motoring.com/getattachme...ta-86.jpg.aspx

Sorry but I had to laugh at comparing wheel fitment to appreciating fine wine. That seems like a bit of a stretch. It's a personal preference, that's all. Another example: some people care about not having fake fender vents, some prefer the look regardless.

The 86 is probably designed like that to house a variety of aftermarket wheels, so you can go as big or as wide as you want in the aftermarket. It's perfect for being flexible to the people who care about having big wheels, perfect fitment, wide sticky tires - and those that prefer the softer ride of the stock smaller wheels.

catharsis I don't know why you're so sure sunken wheels are better for drag. It's something that isn't so easy to answer, and probably can vary a lot based on how the rest of the car is set up, and even on the rims themselves. The way the bodywork flows around the wheel matters too. For example, a lot of cars have bodywork that curves inward, so in that situation what is "flush"? If it's flush with the top of the fender, you're exposing the tire to clean airflow. If the body is like that LFA where there's no inward curve and the bodywork is flat, things are different.

Personally I don't think offset is important for aesthetics, sunken in wheels look fine to me. The thing I don't like about this car is that the wheel wells look mismatched with the wheels, as the gap distance vs. wheel diameter is so big. Looks cheap and like they didn't pay any attention to it.

Other people have discerning tastes and you can have the finest whine possible but that doesn't change the fact that what you're saying is better is only a matter of personal preference. You act like nobody else can tell just because they don't like the same thing as you but the simple fact is that it's not a matter of "flush is better". You may personally think that but a lot of people also disagree, it's not because they don't know any better, they just have different tastes.

Trust me buddy, a lot of people "understand the difference" they just don't want their cars to look like a dragstrip racer with oversized wheels. I know, you can tell me that the wheels could be the exact same width and still be flush with the car and blah blah blah. But it's still imitating that look, it doesn't make a car look good like a sports car, it makes it look like some idiot tried to turn it into a muscle car which to me is the same exact thing as "ricing" a car out with big wings or "ghettofying" a car with gigantic rims, you're just appealing to dragstrip community instead of the import or hip-hop people.


They rolled the rims for you, you can "fix" it easily enough, just like they left the ECU open and set things up to be fairly easy to tune for people who care about performance and offer great big wings and red brake kits for people who care about that. It's not that they didn't finish what they were doing on any of those things, they've left options there to easily change the car to your tastes no matter what they may be.

^Chill out, buddy. I'm not trying to fit into any kind of image or scene. It's just an aesthetic preference I developed after I noticed the difference with my first set of aftermarket wheels.

Ok I can see wheel width being a cost issue. Wider wheels and tires cost more and would bring the cost of this car up. So they chose the narrowest possible wheels that are still within a safety threshold tolerance.

Ride height is also a tradeoff to cost and comfort. If the automaker reduces wheel gap, it'd need firmer shocks to accomodate reduced stroke travel which cost more and sacrifice comfort. Expensive/uncomfortable shocks don't make sense on a mass-produced affordable car.

But I still don't see why offset has to be kept ugly. I'm not convinced that it's an aerodynamics issue (case in LFA, Cayman, etc.). I don't buy that it's so it can accomodate wider aftermarket wheels because wider wheels can be accomplished regardless of factory offset. Is there any sacrifice in designing a wheel that juts 15mm farther from the hub (wheel width maintained)? If anything, it hurts more than it helps to sell the car on appearance.

No switchlanez, wheel gap has nothing to do with ride height...it's a matter of making the body panel closer to the wheel at the same ride height...lol

Reducing ride height is what we consumers do in the aftermarket to "fix" the perceived ugly looks, as we can't make new body panels that look better.

SUBARU.

Ok this is the only argument I can think of that warrants the factory offset: It's matched to the travel of the factory suspension under full compression.

http://i41.tinypic.com/24g4xw7.png

Maybe a more sophisticated suspension could allow for a more negative offset but they couldn't do it because of cost? I can't prove or disprove any of this; just a hunch.

Picture is somewhat accurate but you're forgetting the camber change that occurs under compression. In the rear you will gain negative camber (the top of the wheel points more inwards) because of the multi-link layout. The fronts, however, won't since they're macpherson struts. You're more likely to get rubbing issues with "flush" fitments on cars with macpherson struts like VW's. To combat that issue a lot of VW owners add a ton of negative static camber which makes the car look kind of ridiculous in the end and while it may help in corners it provides much less grip under acceleration and braking. From a performance point of view it doesn't make much sense.

Ok, thanks for the input. I forgot to take camber into account.

Here are some pictures that may better illustrate the fine point I'm trying to make. The 370Z, Miata, and Gen Coupe are the nearest competitors and can still accomodate larger aftermarket wheels. Look at how the body panels line up around the stock wheels.

http://i42.tinypic.com/16a32iw.jpg

http://i42.tinypic.com/35arrwg.jpg

http://i40.tinypic.com/x3y1ir.jpg

My MR2 Spyder stock wheels were fine (TRD wheels had the same offset and width as stock) and just flush enough that I never bothered to change them. Same goes for stock MkII MR2.
https://fbcdn-sphotos-a.akamaihd.net..._4224957_n.jpg

https://fbcdn-sphotos-a.akamaihd.net..._3194318_n.jpg

Ever since I noticed the gumpy fitment in spy shots, I hoped it was only because it was a prototype.
http://1.bp.blogspot.com/-zvlWGN3VSp...-FT-86-131.jpg

But nope, they kept that fitment on the production version. Look at this FR-S lowered on TRD springs. Unlike all the other cars above, these tire sidewalls are completely eclipsed by the body panels by a few centimeters. :barf:
http://i39.tinypic.com/a2r9k8.jpg


Stock wheels should at least look like they belong on the car.

Um switchlanez, thanks for all the pictures, but I don't see the difference...? I don't see what's so ugly? A few centimeters? It's like 1 at most. I think this is a matter of personal taste :P I'd rather have no part of the wheel sticking past the body panels, less drag.

Well I don't know much technical stuff about cars, but it just seems that the fenders overlap the wheels due to the narrowness of the wheels/tires.

This car is a blank canvas, so im guessing they want you to put wider wheels/tires on there.

While true you know that's not the whole story. If the track width is changed, then handling DOES change. I agree it doesn't matter technically where the wheel is in relation to the fender specifically but obviously to increase track width you will get a more flush fitment. I've fine tuned handling by changing track widths before, sometimes resulted in a flush fitment, sometimes not, the looks were never my goal though.

Let's be clear on this subject (directed at those confusing the two, not at fatoni), flush is NOT hellaflush. I see nothing wrong with more or less flush fitments, it's only when you are doing the hellaflush camber, stretched tires, etc that safety issues and handling issues become a more major concern.