2013 GT tire and Wheel fitment questions and recommendations

[yodadeciple]

I need some help from the forums trying to figure out why there is so much gap in my rear tires/wheel well compared to the fronts, and how to get a better wheel/tire setup to correct some of that. Apologies for post being wordy, but tried to include as much info as I could to get some better feedback.

I usually use this for street setup, not much track use, but would eventually like to drag race "officially"

Current setup:
Wheels: Front Niche Targa 20x8.5 front +35 offset / Rear Niche Targa 20x10 +40 offset
Tires: bridgestone potenza s-04 pole position Front 255/35/20 Rear 285/30/20
Suspension mods: Roush All in One Suspension kit
https://www.brenspeed.com/421156.html (Front Coil Springs, Rear Coil Springs, Front Struts, Rear Shocks, Front Stabilizer Bar and Hardware Kit, Rear Stabilizer Bar and Hardware Kit
Rear Jounce Bumpers, lowers all around by 1 inch)

I don't have exact measurements, but there is about a 3.5 to 4 finger gap between the top of the rear tire and the body panel/wheel well (not sure on correct terminology), compared to about a 2 finger gap in the front.

Granted, I understand the fronts are taller, however the tire comparisons I've looked at on https://tiresize.com/calculator don't seem to address the issue. How do I find wheel/tire combos that will be a better fit in this scenario?

Wheels and tires I'm looking at replacing current setup with:
Tires: Pretty set on Michelin Pilot Sport 4s Sizes for rear either 305/30/19's or 305/35/20, since that would have a taller profile in rear, but not sure if that's the best option
Wheels: Something like a 19x11 Shelby CS5 wheels if going to a 19" , or a 20x11 Shelby CS14 if I stay with 20" wheels

NOTE: CS14 wheels are +55 offset I believe, and the CS5 wheels are +50 offset

 

[stkjock]

IIRC, these cars have a factory rake with the rear being higher then the front, there is only about a 1/4 delta in the height of your tires, so that's less than a finger width.

if you are just looking to fill the rear gap, get a taller tire w/ larger sidewall.

a 305/35/20 is about 1.5" taller than you current tire and will certainly close up that gap

 

[Gabe]

Keeping your existing wheels you could swap to a 285/35/20 rear tire which is 1.1" taller than your 285/30/20.
Or 275/40/20 which is almost 2" taller, at 28.6"-28.7" tall.
Either way, half the extra height translates to extra ground clearance and that much more rubber all around.

If you're willing to swap out to a 20x11, do a 305/35/20 like Dave said above, and that will fill up the wheel well nicely

 

[yodadeciple]

Thanks for the replies. Sounds like my research was close to your suggestions. What throws a wrench in my plans (no pun intended) is the fact Michelin doesn't make a 305/35/19 tire in the 4s's and I don't really want the Cup 2's because I'm scared to death of getting caught in the rain here in Michigan, as rain can come out of nowhere.