295/45R20 vs 275/45R21
275/45R21 is a safe swap for 295/45R20 by the usual ±3% rule: the diameter differs by +0.96%.
Speedometer and odometer
With 275/45R21 on a car calibrated for 295/45R20, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.4 mph |
| 60 mph | 60.6 mph |
| 70 mph | 70.7 mph |
| 80 mph | 80.8 mph |
Other sizes close to 295/45R20
- 295/45R20 vs 275/55R20+4.78%
- 295/45R20 vs 255/45R20-4.65%
- 295/45R20 vs 255/50R20-1.36%
- 295/45R20 vs 265/50R20-0.06%
- 295/45R20 vs 245/50R20-2.65%
- 295/45R20 vs 275/45R20-2.33%
- 295/45R20 vs 255/55R20+1.94%
- 295/45R20 vs 235/55R20-0.90%
- 295/45R20 vs 265/45R20-3.49%
- 295/45R20 vs 275/50R20+1.23%
- 295/45R20 vs 295/40R20-3.81%
- 295/45R20 vs 285/50R20+2.52%
Questions
Can I replace 295/45R20 with 275/45R21?
275/45R21 is a safe swap for 295/45R20 by the usual ±3% rule: the diameter differs by +0.96%.
What's the difference between 295/45R20 and 275/45R21?
275/45R21 is 0.29" taller and 20 mm narrower; the sidewall is -0.35". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 275/45R21 fit on 295/45R20 wheels?
No — 295/45R20 needs a 20" wheel and 275/45R21 a 21" wheel. This is a plus/minus-size swap that changes wheels too.