Optional tire sizes for stock 18 inch wheels
 

I want to get a set of Falken RT-615's next spring. Ran them on my old autox car and they are awesome tires. Almost as good as the Hoosier A6's I ran for a season. At any rate, they do not come in 225/45/18. All 18inch sizes that are close are 40 series. I'm not real good on figuring tire sizes so I was hoping for some help.

I want a tire about the same diameter of the stock size tire and have no clearance issues. What have people tried? Can I squeeze a 245 on there?

ummm... try reading the stickies? If not in the S2 forums, they'll be the same for the S1

Short answer: Yes, 245/40 is very popular

Did a google search and got a lot of threads, but nothing with what I was really looking for. Just a lot of random tire size stuff. Most relating to changing rims.

Thanks for the answer. Looks like 245/40/18 RT-615K's will go on this spring! YAY!

your search method is poor.
Found this on my first search
https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/will-245-40r18-tires-fit-stock-2005-18-rims-217325/