Comparison of tire sizes 315/25 R20 and 345/35 R18
315/25R20
315
Tire width 
25
Profile height 
R20
Tire diameter 
478
RPM per km 315mm79mm666mm2091mm
315
25
20
345
35
18
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 666 | 699 | +33 (+5%) | ||
| Width, mm | 315 | 345 | +30 (+9.5%) | ||
| Circumference, mm | 2091 | 2195 | +104 (+5%) | ||
| Profile height, mm | 79 | 121 | +42 (+53.2%) | ||
| RPM per km | 478 | 456 | -22 (-4.6%) | ||
| Clearance change, mm | +17 | ||||
| Result: | The diameter differs by 5%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 105 |
| Difference (km/h) | 5 |
Sizes for comparison of tires 315/25 R20
R20
R19 -1
R21 +1
R18 -2
Sizes for comparison of tires 345/35 R18
R18
R19 +1
R20 +2
