20.5/2.25 = 9.1 recurring (that is, 9.1111...)
what is the diameter difference from a 205/65/16 vs. 225/60/16
205
34.1667
225 divided your 25 = 9
205
28.125
90
18.75
3 divided into 225 = 0.013333333333333334
9.375
9.375
450 divided by two would equal 225.