275/35R22 vs 245/45R21
245/45R21 is a safe swap for 275/35R22 by the usual ±3% rule: the diameter differs by +0.35%.
Speedometer and odometer
With 245/45R21 on a car calibrated for 275/35R22, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.2 mph |
| 70 mph | 70.2 mph |
| 80 mph | 80.3 mph |
Other sizes close to 275/35R22
- 275/35R22 vs 265/40R21-0.79%
- 275/35R22 vs 275/40R22+3.66%
- 275/35R22 vs 265/40R22+2.60%
- 275/35R22 vs 265/35R22-0.93%
- 275/35R22 vs 285/35R22+0.93%
- 275/35R22 vs 285/40R22+4.73%
- 275/35R22 vs 275/40R21+0.28%
- 275/35R22 vs 315/35R21+0.35%
- 275/35R22 vs 295/35R22+1.86%
- 275/35R22 vs 315/35R22+3.73%
- 275/35R22 vs 325/35R22+4.66%
- 275/35R22 vs 285/30R22-2.86%
Questions
Can I replace 275/35R22 with 245/45R21?
245/45R21 is a safe swap for 275/35R22 by the usual ±3% rule: the diameter differs by +0.35%.
What's the difference between 275/35R22 and 245/45R21?
245/45R21 is 0.10" taller and 30 mm narrower; the sidewall is +0.55". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 245/45R21 fit on 275/35R22 wheels?
No — 275/35R22 needs a 22" wheel and 245/45R21 a 21" wheel. This is a plus/minus-size swap that changes wheels too.