Hi guys, according to the article on tirerack.com about tire sizing, the sidewall height on my 245/40/18 tires should come up as 3.85in. I measured the sidewall, and it's more like 2.5in. So... I came up with 3.85 from 245 / 25.4 x .4 ... why isn't it matching up?

 

Possibly it includes the bead on the tire. idk though