going with 17s

[chuckster]

Well I went down to wareham this AM and after going round and round, I decided to go with 17's I'm going with the 2015 IRS and all the work and expense to make it work with 15's is just not justified for me.
So it's 17 X 9's all the way around. my question now is what size tires? Also, same size tire front and rear, or different F/R? Finished installing a ductless mini split heat/AC unit in my garage yesterday
so now I can work on the car regardless of the weather.

[GoDadGo]

Since you are going with 17 X 9's on all four corners, I'd suggest 255/40-17's up front and 275/40-17's out back.
It will give you a little rake, cheats the eye a bit and both tires work well on 17 X 9's.
We have that combo on my son's 2000 Camaro:
https://youtu.be/svZX2BMSDEs

My only concern is that the FIA car may have issues with the 255's up front so check with Dan at Factory Five or a 289 FIA owner before you buy.
NITTO's Website may be of some help too:
http://www.nittotire.com/passenger-tires/nt555-g2-ultra-high-performance-tire/

[CobraboyDR]

Well I went down to wareham this AM and after going round and round, I decided to go with 17's I'm going with the 2015 IRS and all the work and expense to make it work with 15's is just not justified for me.
So it's 17 X 9's all the way around. my question now is what size tires? Also, same size tire front and rear, or different F/R? Finished installing a ductless mini split heat/AC unit in my garage yesterday
so now I can work on the car regardless of the weather.What work and expense is necessary to make the new IRS work with the 15's?

I'm pondering this myself. I want 15's for the look and want pin-drives, but I also want IRS and not a solid axle.

[chuckster]

Wilwoods from Gordon Levy, $995 frt $995 Rr. parking brake $200 Avons $1600 it adds up.

[chuckster]

Talked to Dan at FFR this AM, and I've settled on my tires. I'm going with 275 40 r17s on the rear, and 245 45 r17s on the front
The 275s are 25.7"dia. And 4.3"sidewalls, with a 10.8"width. And the 245s are 25.7"dia. 4.3"sidewalls and 9.6" width.
I plan to put "tred wear" billboard letters on the sidewalls. For tires I'm going with Riken Raptors, they seem to get pretty good reviews.

[Jimtmich]

Do you have any pictures of how it turned out?

[GoDadGo]

Talked to Dan at FFR this AM, and I've settled on my tires. I'm going with 275 40 r17s on the rear, and 245 45 r17s on the front
The 275s are 25.7"dia. And 4.3"sidewalls, with a 10.8"width. And the 245s are 25.7"dia. 4.3"sidewalls and 9.6" width.
I plan to put "tred wear" billboard letters on the sidewalls. For tires I'm going with Riken Raptors, they seem to get pretty good reviews.

I'd suggest going up to 285/40-17s instead of the 275/40-17s to fill the rear wheel wells a bit more.
They are just a tad taller than the 245/45-17s.
You can see what the this combo look like on the video shown below:

https://youtu.be/IGYtX-3p7xk

[chuckster]

My roadster is a 289, and the 275s are about all you can fit in the wheel wells.