255/50R21 vs 295/40R22
295/40R22 is a safe swap for 255/50R21 by the usual ±3% rule: the diameter differs by +0.81%.
Speedometer and odometer
With 295/40R22 on a car calibrated for 255/50R21, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.4 mph |
| 60 mph | 60.5 mph |
| 70 mph | 70.6 mph |
| 80 mph | 80.6 mph |
Other sizes close to 255/50R21
- 255/50R21 vs 255/55R20+0.01%
- 255/50R21 vs 275/50R20-0.68%
- 255/50R21 vs 275/45R21-0.95%
- 255/50R21 vs 285/40R22-0.20%
- 255/50R21 vs 285/45R21+0.19%
- 255/50R21 vs 295/40R21-2.41%
- 255/50R21 vs 285/50R20+0.58%
- 255/50R21 vs 265/45R21-2.09%
- 255/50R21 vs 285/40R21-3.42%
- 255/50R21 vs 275/40R21-4.44%
- 255/50R21 vs 315/35R21-4.38%
- 255/50R21 vs 315/40R21-0.38%
Questions
Can I replace 255/50R21 with 295/40R22?
295/40R22 is a safe swap for 255/50R21 by the usual ±3% rule: the diameter differs by +0.81%.
What's the difference between 255/50R21 and 295/40R22?
295/40R22 is 0.25" taller and 40 mm wider; the sidewall is -0.37". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 295/40R22 fit on 255/50R21 wheels?
No — 255/50R21 needs a 21" wheel and 295/40R22 a 22" wheel. This is a plus/minus-size swap that changes wheels too.