Comparison of tire sizes 155/70 R12 and 145/70 R12
155/70R12
155
Tire width 
70
Profile height 
R12
Tire diameter 
610
RPM per km 155mm109mm522mm1639mm
155
70
12
145
70
12
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 522 | 508 | -14 (-2.7%) | ||
| Width, mm | 155 | 145 | -10 (-6.5%) | ||
| Circumference, mm | 1639 | 1595 | -44 (-2.7%) | ||
| Profile height, mm | 109 | 102 | -7 (-6.4%) | ||
| RPM per km | 610 | 627 | +17 (+2.8%) | ||
| Clearance change, mm | -7 | ||||
| Result: | The diameter differs by -2.7%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 97.3 |
| Difference (km/h) | -2.7 |
Sizes for comparison of tires 155/70 R12
R12
R13 +1
R14 +2
Sizes for comparison of tires 145/70 R12
R12
R13 +1
