Comparison of tire sizes 155/70 R12 and 155/70 R13

155/70R12
155 Tire width
70 Profile height
R12 Tire diameter
610 RPM per km
155mm109mm522mm1639mm
155
70
12
155
70
13
Parameters Sizes Old New
Diameter, mm522547+25 (+4.8%)
Width, mm1551550 (0%)
Circumference, mm16391719+80 (+4.9%)
Profile height, mm1091090 (0%)
RPM per km610582-28 (-4.6%)
Clearance change, mm+13
Result:
The diameter differs by 4.8%.
Speedometer reading (km/h)
Real speed (km/h)104.9
Difference (km/h)4.9

Sizes for comparison of tires 155/70 R12

R12
R13 +1
R14 +2

Sizes for comparison of tires 155/70 R13

R13
R14 +1
R15 +2