I run continental r comps on my race car on road courses with NASA. They are 275/35/18. I'm about to buy new rims for my '84 and wondering could I go with that size with minimal rubbing in the front? It would help me to be able to use the same tire size on all 4s and transfer tires from one car to the other. How much sterring input would I loose? Are we talking 5º or like an entire half turn of the wheel. A little rub pulling onto grid or out from the paddock isn't a big deal but a lot may be annoying...

I have searched but after 30min of reading about drag racera and how 255 will do well I figured I'd just post. This is still a street car sometimes but maybe sees 1000 miles a year off the track.

 

That will fit just fine, use a 9.5 wheel with zero offset with stock brakes or a tad positive offset with aftermarket. That works out to about 5.5 to 5.75" os backspacing, honeslty since the the are 18" wheels I would use a tad more backspacing and tuck them a little better, you will lose a tiny bit of stering angle but not much. I use. 18x10.5 up front with what equates to a hair over 6" of bs with stock brakes and they fit quite well and the turning radius is actually decent.

 

Do you have problems with the tire sticking out from the well? I would more than likely lower it for a lower center of gravity and don't want it to be sticking out from the fender wells...

 

No they xfit very well, but need a bit more camber to fit. They actually tuck betten than the crosslaces I had on the car before

 

big mods on here, stansirocz on frrax uses those tires on z06 wheels with spacers. They're probably a little stretched on a 10.5" wheel.

I had 305/35r 18's on my car and honestly steering lock wasnt an issue for me except in a parking lot.

 

I've had Phil's car in the shop and his wheels fit very nice - tucked in a bit and from what I can tell, no major issues with rubbing.

As a wheel manufacturer, I can give you some useful advice:

1) Having the same sized tire all around is great for rotation and spares

2) Optimal wheel width is 10", but 9.5" or 10.5" will do also

3) 0 offset on a 9.5" wheel will bring the outer edge of the tire to the end of the wheel well. Our 17" wheels are of that variety. With an 18" wheel, you shouldn't have to worry about wheel to tie rod clearance (it tucks in) and you can run +12mm for some tuck in front with a 9.5" wheel. The only contact point could be the struts in front with a lot of BS.

4) 17" may be an idea for your 84 - they weigh less, offer more sidewall protection, and offer lower priced tires with a similar tread pattern selection.