clawhammer

I was looking at Discount Tire's size comparison calculator, and a question came up. AP1 S2000s have 225/45 rear tires, but they're not a real 225, they're more like a 245. So to get the same diameter tire on an 18" wheel, do you put 225 or 245 in the calculator for the correct size? Here's the link to the calculator: http://www.discounttire.com/dtcs/infoTireMath.dos

TR-S2K

AP1 OEM rear size is 225/50-16. For 18 in. wheel, you want to use this size: 255/35-18; The diameter is less than 0.2 in larger than OEM.

clawhammer

I was aware of that. But that 225 is not a REAL 225, it's more like a 245. But my question still stands. Should you be using 225 as the base or 245?

TR-S2K

If you want to use 245, then you should use aspect ratio of 45.