275/40R20 vs 265/45R20
265/45R20 is a safe swap for 275/40R20 by the usual ±3% rule: the diameter differs by +2.54%.
Speedometer and odometer
With 265/45R20 on a car calibrated for 275/40R20, the speedometer reads 58.5 mph when you're really doing 60, and the odometer under-counts by 2.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.8 mph |
| 45 mph | 46.1 mph |
| 60 mph | 61.5 mph |
| 70 mph | 71.8 mph |
| 80 mph | 82.0 mph |
Other sizes close to 275/40R20
- 275/40R20 vs 245/45R20+0.07%
- 275/40R20 vs 255/45R20+1.30%
- 275/40R20 vs 255/50R20+4.81%
- 275/40R20 vs 245/40R20-3.30%
- 275/40R20 vs 245/50R20+3.43%
- 275/40R20 vs 275/45R20+3.78%
- 275/40R20 vs 225/55R19+0.29%
- 275/40R20 vs 255/40R20-2.20%
- 275/40R20 vs 275/35R20-3.78%
- 275/40R20 vs 285/35R20-2.82%
- 275/40R20 vs 315/35R20+0.07%
- 275/40R20 vs 245/50R19-0.05%
Questions
Can I replace 275/40R20 with 265/45R20?
265/45R20 is a safe swap for 275/40R20 by the usual ±3% rule: the diameter differs by +2.54%.
What's the difference between 275/40R20 and 265/45R20?
265/45R20 is 0.73" taller and 10 mm narrower; the sidewall is +0.36". At an indicated 60 mph you'd actually be doing 61.5 mph.
Will 265/45R20 fit on 275/40R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 265 mm tire and the fender clearance.