I noticed that on TireRack.com, they list the overall diameter of the stock F1's on our cars as "31.5" inches. Yet all the other tires I check the specs on their site for 245/45-18 (including GS-D3's) are around 27".

My car is at Dealer's tonight getting IRS bushing TSB done, so I can't just walk out and measure them.

Are our tires weirdly large? Or are the specs just wrong on TireRack? I'm looking for a replacement tire, and trying to find something in a 255/40-18 (PS2's or Yoko) since none of the best tires are available in 245/45-18.

TireRack must have a glitch...we don't have 31" truck tires.

1010tires.com has a tire size calculator that will tell you exact measurements and you can compare it with others.