18x8 +45 and 225/40-18, what to expect?
 

These are my plans for an aftermarket package. I already bought the wheels but still researching for a good tire. I plan to have them installed after the 1.6k miles break in period. (resisting to install them now coz the car is still "under probation" for defects etc.) I should probably add that given the right tire, I've calculated just about equal weight versus OE.

I've only racked up a few hundred miles but I really love the way the BRZ drives. So my biggest fear is I may be messing with perfection with this plus sized setup. Thoughts?

Btw, for those of you who will say "pics or it didn't happen," here's a teaser for ya...
Attachment 40077

What Prodrives did you get? I'm anxiously awaiting mine from Japan.

going from 215/45/17 17x7 +48 to 225/40/18 18x8 +45 is a conservative and mild up sizing compared to what a lot of members are already running.

staying squared rather than staggered is more important to retaining oversteer/understeer dynamics.

the only difference you will feel will depend on the tires you choose. You will feel differences in grip (most likely the added grip :word:), and the tire noise/comfort/sidewall flex differences depending on the tire you choose.

Curious to know which Prodrives as well. I was thinking of ordering the GC-07J 18x8 +43 til I realized the 18s that fit our cars don't come in concave face. Only flat face with a stepped lug nut pocket, but the side profile looks amazing.

https://fbcdn-sphotos-e-a.akamaihd.n...93213916_n.jpg

This guy must be running 5x114.3 converters to have concave 18s.

http://cdn.speedhunters.com/wp-conte...troof86-47.jpg

I also like the GC-010E from the side profile but at other angles they don't have much depth.

http://prodrive-japan.com/plog/asset...94x770-426.jpg

http://cdn.mkimg.carview.co.jp/minka...3413364/p3.jpg

Where'd you find this photo? I looked all over for how they would have looked on the twins. IMO, the 17x8 I purchased had the best face/disk option with the new GC-07 design.

No, that's just the old style GC-07C. Judging by tire specs given in the Speedhunters article, I'm pretty confident they're 18x8. Plus, AFAIK, Prodrive never made them in a larger size (in 5x100). I'll bet Pentroof is running some spacers though as they look pretty flush.

Yeah, the 17" GC-07J has the face I like but I want to try 18" for a change. A google image search led me to the facebook page of a tuner shop in the Philippines. This angle shows how flat the 18" face is:

https://sphotos-a.xx.fbcdn.net/hphot...03372979_n.jpg


Where can I find specs on this old style GC-07?? I tried looking for older used ones but couldn't find. I'm aware of PFF7 but best fit I could find for 5x100 on those is 18x8 +51.

http://www.pbase.com/saggiowrx/image/42607048.jpg

Maybe I can put the OEM Subaru 5x114.3 hub in the rear to fit the concave GC-07J and keep the flat 5x100 GC-07J up front. Just not sure if that conversion requires swapping out brake components as well...

Ah, interesting. Yeah, I knew what I was getting into with a really flat faced design, but that setup on that particular BRZ doesn't look very good. I suspect the tire choice and use of spacers is part of the problem. I feel the GC-07 design doesn't take well to an aggressive/hellaflush approach. These wheels look best sitting inside the fenders, IMO. In addition to a better face/disk design, because of how the spokes are, 18s tend to look like 19s, which is also why I stayed with 17s.

From what I've seen there really isn't a "concave" GC-07J like the GC-07C. Even in the 9"+ widths, they're still relatively flat faced. For the GC-07C, there are old FS threads floating around, but all I see are 18x7.5 and 17x7.5. I've only seen one 18x8 set in my life, but it could've been a PFF7 just with Prodrive cap. I have no idea since it was so long ago. :shrug: As far as a hub conversion goes, it's an option, but it seems rather cost prohibitive.

@Steve, thanks for your response
@Ro_Ja If I immediately tell you what Prodrives they are, where's the fun in that? :D I'll keep it a mystery for now. Would you mind telling me what you ordered and what specs?
@switchlanez yes, Prodrive is really not the best choice for that flush/stanced look because their usually flat. They're best tucked in just a bit, and that's partly the reason I chose a relatively conservative 8" width and +45 offset. I also figured they're the best compromise between form and function. As it is I'm still worried with how these wheels will alter driving feel.

I was informed by the local distributor that that Prodrives are hard to come by as they are now on a made-to-order basis. If you wanted a specific size, you will have to order and wait 90 days. In fact, some models and specs in the Prodrive-Japan website are said to be discontinued. I was just lucky that the model I wanted was in stock.

Here's another teaser, lol.
Attachment 40172

^The code gives it away lol...
http://prodrive-japan.com/products/g...ain_image2.jpg

And this is the difference between the discontinued GC-07C (top) vs. current GC-07J (bottom). Top is more concave but with enough OEM looking style to not need flush fitment to look right.

http://www.gotuning.com/images/produ...C_BB.thumb_big
http://www.gotuning.com/images/produ...i.thumb_medium

haha I'm keeping quiet too, but if you look above, I might've spilled the beans a little bit. :P I prefer conservative setups. I guess it's due to my interest in the old school days of skinny wheels. I really like how the FR-S feels out of the box and I really didn't want to stray far from how Tada-san setup the car. I'm not building a show car or a race car either.

When I ordered, the dealer told me that my wheels had to be made, so I'm an example of the 3 month wait. Hopefully they arrive in July!

Update: surprisingly and unfortunately, almost all the tire brands and models I checked are out of stock for 225/40 :(

The only one available is the Bridgestone RE002, but I checked it's tire weight and it's a whopping 25.75 pounds! When combined with my Prodrives, I will end up with 44 pounds per corner, or 4 pounds heavier than stock! :(

Now my question would be: can I live with a 4 pound weight penalty? will it have an adverse effect on how the car performs?

There's a rule of thumb that 1 pound of unsprung weight = some mutliple (times 3?) of sprung weight. If my memory serves correct, you'd virtually be adding 48 static lbs. I'm currently rolling 43.4 lbs per corner (18.4 lbs STI wheels + 25 lbs Advans). Any loss in acceleration got so overshadowed by the improved sensation of grip that I didn't notice.

My next wheel/tire combo I'm thinking of (not Prodrives) come in at 45 lbs/corner lol.

Switch, thanks for the info. Maybe I'm just obsessing too much with a few pounds. Just curious: what kind of Advans are you currently running?

Yokohama Advan S.4... a more budget minded model. I wanted to use its sidewall branding for custom white tire letters.