Comparison of tire sizes 245/60 R18 and 255/60 R17

245/60R18
245 Tire width
60 Profile height
R18 Tire diameter
424 RPM per km
245mm147mm751mm2360mm
245
60
18
255
60
17
Parameters Sizes Old New
Diameter, mm751738-13 (-1.7%)
Width, mm245255+10 (+4.1%)
Circumference, mm23602318-42 (-1.8%)
Profile height, mm147153+6 (+4.1%)
RPM per km424431+7 (+1.7%)
Clearance change, mm-7
Result:
The diameter differs by -1.7%.
Speedometer reading (km/h)
Real speed (km/h)98.2
Difference (km/h)-1.8

Sizes for comparison of tires 245/60 R18

R18
R17 -1
R19 +1
R16 -2
R20 +2

Sizes for comparison of tires 255/60 R17

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