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

[serialk11r]

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.

[Alias]

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.

[switchlanez]

^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.

[serialk11r]

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.

[OrbitalEllipses]

Originally Posted by SUB-FT86

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

SUBARU.

[switchlanez]

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.



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.

[scorcherjf]

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.

Originally Posted by switchlanez

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.



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.

[switchlanez]

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.







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.




Ever since I noticed the gumpy fitment in spy shots, I hoped it was only because it was a prototype.


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.



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

[serialk11r]

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.

[Snoopyalien24]

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.

[Dave-ROR]

Originally Posted by fatoni

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

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.

[Dave-ROR]

Originally Posted by switchlanez

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.

No on the cooling. To make a significant change in brake cooling you need to plumb cooling ducts to the center of the rotors (ideally) or at least to the rotor/caliper..

Wheel design can change cooling, but any slight changes in offset I've never seen any real world evidence of.

[86fanatic]

Originally Posted by Dave-ROR

flush is NOT hellaflush

For me it's two sides of the same coin: taking "wheel fitment" way too seriously, borderline choosing "fitment" over other engineering principles of the car.

I don't like fake fender vents, but it's not a deal breaker for me. At least you can always lower the car, or fit wider/bigger tires. I'd have to manufacture a new fender to remove the style detail I don't like.

[Dave-ROR]

Originally Posted by 86fanatic

For me it's two sides of the same coin: taking "wheel fitment" way too seriously, borderline choosing "fitment" over other engineering principles of the car.

I don't like fake fender vents, but it's not a deal breaker for me. At least you can always lower the car, or fit wider/bigger tires. I'd have to manufacture a new fender to remove the style detail I don't like.

Make sure you read my post. At no point did I mention a fitment for style or appearance. One of my cars can be considered flush. It's that way to clear calipers and for increased track, not for looks or style.

I was explaining why some people would want more flush fitments that are not based on appearance.