Sean,
I run currently 215/65 - 15. The first number is the with of the tire,
the 2nd number the aspect ratio, the 3rd the rim diameter. So a 215/65 -
15 tire has a smaler circumfence than a 215/70 - 15.
Here a little table:
Tire Size Comparison
Specification Sidewall Radius Diameter Circumference Revs/Mile
Difference
205/65-15 5.2in 12.7in 25.5in 80.1in 791
0.0%
215/65-15 5.5in 13.0in 26.0in 81.7in 776
2.0%
205/70-15 5.6in 13.1in 26.3in 82.6in 767
3.2%
215/70-15 5.9in 13.4in 26.9in 84.4in 751
5.3%
205/75-15 6.1in 13.6in 27.1in 85.2in 744
6.3%
215/75-15 6.3in 13.8in 27.7in 87.0in 728
8.6%
I used this calculator:
Thomas in Florida
ex '77 Camper
ex '85 Camper
'93 EV MV 5-speed
