I'm thinking about swapping out my '05 STi rims for some SSR Comps. I want to run a 17x7.5 to drop about 6 pounds per wheel. I know that a 225/45/17 will fit fine on the 17x7.5, but I also know that Subaru went to 17x8 in '05 to square off the contact patch of the tire. I doubt that there is any noticeable difference in handling characteristics, but I was wondering if anyone had any experience with this? Are there any other downsides to going with a slightly narrower wheel? When I order the new wheels what offset should I use... the '04 offset?

 

i think 48 offset

 

all other things being equal, the contact patch will be narrower. that being said, the difference is probably insignificant.

 

Unless you are doing autox, the 225 45 17 on a 17 X 7.5 will provide all the traction you could possibly need without the additional unsprung weight of the 17 X 8 and a wider tire. It's just a matter of finding the tire with the amount and kind of traction you want. I run the SSR Comp 17 X 7.5.

 

How do you like them so far? Any noticeable difference in acceleration? I know that they are about 6.25 lbs. lighter than the '05 STi wheels. I plan on running some Kumho MX's which are about 2 lbs. lighter than the Potenza's that come on the car. I had read in a post by one of the guys at the Tire Rack that the rough calculation for equating rotating mass to extra weight was (in this instance) 8.25 lbs. per wheel and tire X 4 wheels X 10 = 330 lbs. Now, typically for every 100 lbs. lost, you gain a tenth in the quarter. I was very curious to hear if you noticed any SOTP difference?

 

My experience is with the '03 WRX Sedan. The change was from the stock 16" wheel at 16 lbs and stock RE 92 205 55 16 tire. In addition to the SSRs mentioned above, the tires are the light Kumho Ecsta MX 225 45 17. The total reduction of unsprung weight (wheel and tire combined) was 18 lbs. I made the change almost two years ago.

Butt dyno observations: Big handling improvements from the 17" wheels and tires and the 45 aspect ratio. Huge increase in dry traction and a modest improvement in rain performance from the Kumho Ecsta MXs.

Acceleration: Because I increased wheel diameter to 17", there was an increase in rotational mass that was not entirely offset by the lighter weight of the SSR and MX. Acceleration was just noticably slower. This slight difference was verified by a slight increase in fuel consumption (about 1 mile per gallon lost in MPG.)

In your case, you are not changing to a larger diameter wheel, so you should notice an improvement in acceleration with the SSR Comps and MXs.

MX are lighter than most performance tires because the sidewall is lighter. This means a reduction in sidewall stiffness which should not be noticable unless you are doing autox. Sidewall flex in the MX can be reduced by increasing air pressure a few lbs.

I am very happy with the way the Comps and MX have improved performance capabilities of the WRX. I have 30K miles on the MXs and will replace them soon with another set. I use the MXs all year long and like the way they drive in the rain. The balance of dry and wet traction is optimal for me.

The SSR Competition is a custom version of the SSR Type-C semi-solid one-piece forged wheel and was made exclusively for Tire Rack. The Competition is hub-centric and clear coated. SSR changed to new owners last year, and it looks like the premium priced one-piece Type-C will no longer be made. The last time I checked Tire Rack (a few weeks ago) the 17" Comps were gone.

The JDM version of SSR Type-C (non hubcentric and without clear coat) was still available from Gruppe-S a few weeks ago and probably some other vendors as well.

I think Tire Rack still has some of the one-piece SSR GT-2 wheels on close-out. They are only slightly heavier than the Comps and stronger (not that the Comps were plenty strong.)

In the the 16 years I've driven on alloy wheels, I've bent a few. I haven't damaged a SSR yet in two years of occasional potholes and RR tracks, but I'm glad I bought a set of five!

 

How does the JDM version compare in looks, performance, weight, and price?

 

Except for the differences listed, they are identical (I don't know if the JDM has the machined lip or cap, which is a minor decorative plus). They are both SSR Type-C. Make sure the bolt pattern and offset is right. The Comps on my WRX are 50 offset.

 

Thanks. I called Gruppe-S and they said that the JDM's don't have a polished lip which I insist on having. If the Tire Rack is out and I can't get them, then I may have to step up to a set of Volk LE-28N's. I'm not thrilled about the extra dough though. Hopefully I can find a set of SSR's and sell the stock wheels quickly.