Yes, I've used the search tool to death, as well as google But now I'm just confused I am putting forged COR monoblocks on my Nissan 370z 2012 roadster sport touring, which comes originally with Bridgestone potenza and 19" Rays, 19x9F and 19x10R. I'm putting on COR rims: 20x9 front 20x11 rear In trying to find the right tire and tire size I've gone nuts! Prerequisite data: 1. In moving from "19 to "20 tire, I want to preserve the exact rolling diameter, which from research is between 26.5 and 26.2 on the 19" rays and BR Potenza the car comes with. I want to preserve the size and geometry so that speedo and other factors are minimized and not impacted. 2. I also don't want to sacrifice too much comfort which can easily be done in moving to a 20" rim and the wrong tire, from a 19" rim. 3. I don't want tire mobility and steering rotation to rub or impact any structures in the wheel well. 4. I want the tire to look correct on rim so that it doesn't squish out or look tucked in, but proportionally correct to the rim. The rep at COR for my wheels suggested these tire sizes: 245/35/20 fronts /// Either 285/30/20 *or 295/30/20 *For the rear My problem is this (1) The 285/30/20 by Nitto, BR, and Pirelli is only approved to "10.5 rims, not "11 rims, The 295/30/20 looked to have better official fitment specs to a 20x11 rim. Some wheel manufacturers even went as high as a 305 on the 11rim ----So it sounds like 295/30-20 is correct for the rear.---- However: (2) The front, every monoblock wheel firm on the suggested tire recommends the 255/35-20 for the 20x9 wheel on their sites, but the COR rep suggest a 245/35-20 So... With my pre requisites, what do I buy for tires. I don't go to the track, this is more sport and comfort and aesthetics to me. So what tire size and recommended brand? Thank you for any help, I've learned in this forum that it pays to be specific Thank you [url=http://www.corwheels.com/f1-forma/]COR F1 Forma Monoblock Wheels | Competition Series[/url]