Comparison of tire sizes 145/70 R12 and 155/70 R12

145/70R12
145 Tire width
70 Profile height
R12 Tire diameter
627 RPM per km
145mm102mm508mm1595mm
145
70
12
155
70
12
Parameters Sizes Old New
Diameter, mm508522+14 (+2.8%)
Width, mm145155+10 (+6.9%)
Circumference, mm15951639+44 (+2.8%)
Profile height, mm102109+7 (+6.9%)
RPM per km627610-17 (-2.7%)
Clearance change, mm+7
Result:
The diameter differs by 2.8%.
Speedometer reading (km/h)
Real speed (km/h)102.8
Difference (km/h)2.8

Sizes for comparison of tires 145/70 R12

R12
R13 +1

Sizes for comparison of tires 155/70 R12

R12
R13 +1
R14 +2