295/30R20 vs 245/40R20
245/40R20 is a safe swap for 295/30R20 by the usual ±3% rule: the diameter differs by +2.77%.
Speedometer and odometer
With 245/40R20 on a car calibrated for 295/30R20, the speedometer reads 58.4 mph when you're really doing 60, and the odometer under-counts by 2.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.8 mph |
| 45 mph | 46.2 mph |
| 60 mph | 61.7 mph |
| 70 mph | 71.9 mph |
| 80 mph | 82.2 mph |
Other sizes close to 295/30R20
- 295/30R20 vs 245/40R19-0.93%
- 295/30R20 vs 255/40R19+0.23%
- 295/30R20 vs 245/35R20-0.80%
- 295/30R20 vs 255/35R20+0.22%
- 295/30R20 vs 275/35R20+2.26%
- 295/30R20 vs 255/40R20+3.94%
- 295/30R20 vs 225/45R19+0.01%
- 295/30R20 vs 285/35R19-0.42%
- 295/30R20 vs 285/35R20+3.28%
- 295/30R20 vs 285/30R20-0.88%
- 295/30R20 vs 275/30R20-1.75%
- 295/30R20 vs 265/35R20+1.24%
Questions
Can I replace 295/30R20 with 245/40R20?
245/40R20 is a safe swap for 295/30R20 by the usual ±3% rule: the diameter differs by +2.77%.
What's the difference between 295/30R20 and 245/40R20?
245/40R20 is 0.75" taller and 50 mm narrower; the sidewall is +0.37". At an indicated 60 mph you'd actually be doing 61.7 mph.
Will 245/40R20 fit on 295/30R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.