Current wheel/tyre	New wheel/tyre
145 155 165 175 185 190 195 205 215 225 230 235 245 255 265 275 285 295 305 315 325 335 / 30 35 40 45 50 55 60 65 70 75 80 82 85 100 R 12 13 14 15 15.5 16 16.5 17 18 19 19.5 20 21 22 23	145 155 165 175 185 190 195 205 215 225 235 245 255 265 275 285 295 305 315 325 335 / 30 35 40 45 50 55 60 65 70 75 80 82 85 100 R 12 13 14 15 16 16.5 17 18 19 19.5 20 21 22 23
Current RR:mm	New RR:mm
Current circumference:mm	New circumference:mm
Difference in circumference:mm or %
Global Tyres recommends an Upsizing only if the difference if less than 2%
So when your speedo reads 70kmph, you're actually travelling at kmph