Comparison of tire sizes 225/45 R17 and 205/40 R18

225/45R17
225 Tire width
45 Profile height
R17 Tire diameter
502 RPM per km
225mm101mm634mm1993mm
225
45
17
205
40
18
Parameters Sizes Old New
Diameter, mm634621-13 (-2.1%)
Width, mm225205-20 (-8.9%)
Circumference, mm19931952-41 (-2.1%)
Profile height, mm10182-19 (-18.8%)
RPM per km502512+10 (+2%)
Clearance change, mm-7
Result:
The diameter differs by -2.1%.
Speedometer reading (km/h)
Real speed (km/h)97.9
Difference (km/h)-2.1

Sizes for comparison of tires 225/45 R17

R17
R16 -1
R18 +1
R15 -2
R19 +2

Sizes for comparison of tires 205/40 R18

R18
R17 -1
R19 +1
R16 -2