Comparison of tire sizes 145/70 R12 and 155/65 R13

145/70R12
145 Tire width
70 Profile height
R12 Tire diameter
627 RPM per km
145mm102mm508mm1595mm
145
70
12
155
65
13
Parameters Sizes Old New
Diameter, mm508532+24 (+4.7%)
Width, mm145155+10 (+6.9%)
Circumference, mm15951670+75 (+4.7%)
Profile height, mm102101-1 (-1%)
RPM per km627599-28 (-4.5%)
Clearance change, mm+12
Result:
The diameter differs by 4.7%.
Speedometer reading (km/h)
Real speed (km/h)104.7
Difference (km/h)4.7

Sizes for comparison of tires 145/70 R12

R12
R13 +1

Sizes for comparison of tires 155/65 R13

R13
R12 -1
R14 +1