Comparison of tire sizes 235/45 R20 and 245/40 R20
235/45R20
235
Tire width 
45
Profile height 
R20
Tire diameter 
442
RPM per km 235mm106mm720mm2260mm
235
45
20
245
40
20
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 720 | 704 | -16 (-2.2%) | ||
| Width, mm | 235 | 245 | +10 (+4.3%) | ||
| Circumference, mm | 2260 | 2212 | -48 (-2.1%) | ||
| Profile height, mm | 106 | 98 | -8 (-7.5%) | ||
| RPM per km | 442 | 452 | +10 (+2.3%) | ||
| Clearance change, mm | -8 | ||||
| Result: | The diameter differs by -2.2%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 97.9 |
| Difference (km/h) | -2.1 |
Sizes for comparison of tires 235/45 R20
R20
R19 -1
R21 +1
R18 -2
R22 +2
Sizes for comparison of tires 245/40 R20
R20
R19 -1
R21 +1
R18 -2
R22 +2