Comparison of tire sizes 265/65 R18 and 285/50 R20
265/65R18
265
Tire width 
65
Profile height 
R18
Tire diameter 
397
RPM per km 265mm172mm802mm2519mm
265
65
18
285
50
20
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 802 | 793 | -9 (-1.1%) | ||
| Width, mm | 265 | 285 | +20 (+7.5%) | ||
| Circumference, mm | 2519 | 2491 | -28 (-1.1%) | ||
| Profile height, mm | 172 | 143 | -29 (-16.9%) | ||
| RPM per km | 397 | 401 | +4 (+1%) | ||
| Clearance change, mm | -5 | ||||
| Result: | The diameter differs by -1.1%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 98.9 |
| Difference (km/h) | -1.1 |
Sizes for comparison of tires 265/65 R18
R18
R17 -1
R19 +1
R16 -2
R20 +2
Sizes for comparison of tires 285/50 R20
R20
R19 -1
R21 +1
R18 -2
R22 +2