Comparison
275/45 R20 vs 255/35 R21
Compared to 275/45 R20, 255/35 R21 is 43.6 mm shorter and changes the speedometer reading by -5.77%.
Current Tire
275/45R20
New Tire
255/35R21
275/45 R20
255/35 R21
Ground line · scaled comparison
Not Recommended
Over 5% — speedometer & ABS may misread
Diameter change
-43.6 mm
-5.77%
Speedometer at 100
94.2 km/h
-5.77% error
Ground clearance
-21.8 mm
ride height delta
Sidewall change
-34.5 mm
revs/km: 447.1
Permalink for this comparison:
/compare/275-45-r20-vs-255-35-r21Detailed comparison
| Metric | 275/45 R20 | 255/35 R21 | Difference |
|---|---|---|---|
| Overall diameter | 755.5 mm | 711.9 mm | -43.6 mm (-5.77%) |
| Sidewall height | 123.8 mm | 89.3 mm | -34.5 mm |
| Circumference | 2.373 m | 2.236 m | -137.0 mm |
| Revs / km | 421.3 | 447.1 | +25.8 |
| Ground clearance | reference | -21.8 mm | -21.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 94.2 km/h | -5.77 km/h |
Verdict: danger
Over 5% diameter difference — likely to affect speedometer accuracy, ABS calibration and gearing. Not recommended without professional review.
Back to
275/45 R20
Back to
255/35 R21