As you've said. I looked it up, and the 20" 255/60R20 has almost the exact same outer circumference as the 21" 255/55R21. The difference is insignificant.
How are the rolling diameter differences between the R2's wheel options integrated into its speedometer and odometer readings?
I ask, because there have been a number of online discussions about the advantages of taking delivery with the 20" all-terrain wheels because eventual replacement of...