King Tut

The 245 Hoosiers will definitely work better on a 10" or wider wheel, but they will fit no problem with the offset you have. I run mine on 17x10 +55s.

RedCelica

245/40 hoosiers are as wide as a normal 275/35 tire. You'd really be stuffing 245s onto a 9" wheel. While you *could* do it, I would advise wider wheels. For example, a 225/40/17 hoosier has the same fitment onto a 9" wheel as a 255/40/17 Toyo RR. I have no idea how they get away with it, but they do.

f20kills

unless the info is off on Tire Rack, a 275/40/17 Yoko measures 11.1 section width and Hoosier 245 at 10.3. Its closer to a 255 (10.2 RE71R) than a 275. I cant find any info on a 35/17 except in a hoosier (11)

RedCelica

Gotcha...yeah looking at the RT615K, it's 10.8" in 275/40 Maxxis RC1 in 275/35 which is 10.8 section. Not saying it won't work for him, but he'd be much better off with a wider wheel, wouldn't you agree?

f20kills

For sure...agreed!

Going from a 10" to trying a 9"..10" is the wheel to have for those sizes.

DHonovich

I only made 205whp peak so I have room since I weigh 2650 on the scales with me in the car

DHonovich

It looks my toyoRR in 255 (10.9") are a little wider than the hoosier 245 (10.3") so I guess they will be fine for clearance.

BlueBarchetta

actually I don't think you are correct. Modified roofline is not one of the approved "aero mods" for ST4
under 7.3.2 scroll down, you will find the section of permissible aero mods for ST4.
You can do all the things listed in 7.3.2.D.1, plus the limited specific list in 7.3.2.D.2. Those are the only things you are allowed to do. So the reference to power modification factor for windshield frame or roofline change, only applies to ST1-3.

I would expect further restrictions in ST 5 and 6 when they are implemented.

Im not trying to shoot down your idea of running in ST4, and welcome the chance to run with you. Just trying to point out the rule, so you know going in. Also, I think they need to develop a specific section for ST4 rules/limitations to make it easier to understand

RedCelica

All this talk has got me thinking...I wonder if running a 235/40/17 would actually perform better (ie: faster lap times, not looking at shear mechanical grip) than running a 255/40 Toyo RR. 2 lbs lighter, 1" shorter for better gearing, better side wall geometry on a 9" wheel

f20kills

I'll have to disagree. Highlighted in blue for TT4 they allow you to remove your windshield and frame. 7.3.2 B2 Which includes roof line change. It states "additional" limitations on top of the rules that apply to all. Just like you can run A7s but you're taking massive points for them.