Comparison of tire sizes 155/70 R12 and 155/65 R13

155/70R12
155 Tire width
70 Profile height
R12 Tire diameter
610 RPM per km
155mm109mm522mm1639mm
155
70
12
155
65
13
Parameters Sizes Old New
Diameter, mm522532+10 (+1.9%)
Width, mm1551550 (0%)
Circumference, mm16391670+31 (+1.9%)
Profile height, mm109101-8 (-7.3%)
RPM per km610599-11 (-1.8%)
Clearance change, mm+5
Result:
The diameter differs by 1.9%.
Speedometer reading (km/h)
Real speed (km/h)101.9
Difference (km/h)1.9

Sizes for comparison of tires 155/70 R12

R12
R13 +1
R14 +2

Sizes for comparison of tires 155/65 R13

R13
R12 -1
R14 +1