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

[typericey]

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...

[Ro_Ja]

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

[Steve]

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 ), and the tire noise/comfort/sidewall flex differences depending on the tire you choose.

[switchlanez]

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.



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



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

[Ro_Ja]

Originally Posted by switchlanez

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.

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.

Originally Posted by switchlanez

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

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.

[switchlanez]

Originally Posted by Ro_Ja

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.

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:

Originally Posted by Ro_Ja

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.

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.



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...

[Ro_Ja]

Originally Posted by switchlanez

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:

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.

Originally Posted by switchlanez

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.

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...

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.

[typericey]

@Steve, thanks for your response
@Ro_Ja If I immediately tell you what Prodrives they are, where's the fun in that? 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.

[switchlanez]

^The code gives it away lol...


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.

[Ro_Ja]

Originally Posted by typericey

@Ro_Ja If I immediately tell you what Prodrives they are, where's the fun in that? 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.

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!

[typericey]

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?

[switchlanez]

Originally Posted by typericey

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.

[typericey]

Originally Posted by switchlanez

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?

[switchlanez]

Originally Posted by typericey

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.