Comparison of tire sizes 255/40 R20 and 275/35 R21
255/40R20
255
Tire width 
40
Profile height 
R20
Tire diameter 
447
RPM per km 255mm102mm712mm2237mm
255
40
20
275
35
21
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 712 | 726 | +14 (+2%) | ||
| Width, mm | 255 | 275 | +20 (+7.8%) | ||
| Circumference, mm | 2237 | 2280 | +43 (+1.9%) | ||
| Profile height, mm | 102 | 96 | -6 (-5.9%) | ||
| RPM per km | 447 | 439 | -8 (-1.8%) | ||
| Clearance change, mm | +7 | ||||
| Result: | The diameter differs by 2%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 101.9 |
| Difference (km/h) | 1.9 |
Sizes for comparison of tires 255/40 R20
R20
R19 -1
R21 +1
R18 -2
R22 +2
Sizes for comparison of tires 275/35 R21
R21
R20 -1
R22 +1
R19 -2
