[Rev]

The 215 stands for the side wall width (215 mm). The 65 stands for the aspect ratio (65% of the 215 mm = the distance from the inside diameter of the tire to the ouside diameter. The 16 means a 16" rim.

245mm X .50(aspect ratio) = 122.5mm = 4.82"(inside diameter to outside) X 2 = 9.64". Add that to the rim diameter and you get about 25.6" tire diameter or 25.6" X 3.14 = 79.5" circumfrence.

215 X .65 = 139.75 = 5.50 X 2 =11. Add that to 16 you would have 27" tire dameter or 27 X 3.14 = 84.75 circumfrence.

From what I calculate, the 215/65/16 would be somewhat taller. Aspect ratio makes a lot of difference in the diameter of the tire.

Rev