Comparison of tire sizes 275/55 R20 and 275/65 R18
275/55R20
275
Tire width 
55
Profile height 
R20
Tire diameter 
393
RPM per km 275mm151mm811mm2546mm
275
55
20
275
65
18
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 811 | 815 | +4 (+0.5%) | ||
| Width, mm | 275 | 275 | 0 (0%) | ||
| Circumference, mm | 2546 | 2559 | +13 (+0.5%) | ||
| Profile height, mm | 151 | 179 | +28 (+18.5%) | ||
| RPM per km | 393 | 391 | -2 (-0.5%) | ||
| Clearance change, mm | +2 | ||||
| Result: | The diameter differs by 0.5%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 100.5 |
| Difference (km/h) | 0.5 |
Sizes for comparison of tires 275/55 R20
R20
R19 -1
R21 +1
R18 -2
R22 +2
Sizes for comparison of tires 275/65 R18
R18
R17 -1
R19 +1
R16 -2
R20 +2