295/25R22 vs 295/30R21
295/30R21 is a safe swap for 295/25R22 by the usual ±3% rule: the diameter differs by +0.58%.
Speedometer and odometer
With 295/30R21 on a car calibrated for 295/25R22, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.3 mph |
| 70 mph | 70.4 mph |
| 80 mph | 80.5 mph |
Other sizes close to 295/25R22
Questions
Can I replace 295/25R22 with 295/30R21?
295/30R21 is a safe swap for 295/25R22 by the usual ±3% rule: the diameter differs by +0.58%.
What's the difference between 295/25R22 and 295/30R21?
295/30R21 is 0.16" taller and 0 mm wider; the sidewall is +0.58". At an indicated 60 mph you'd actually be doing 60.3 mph.
Will 295/30R21 fit on 295/25R22 wheels?
No — 295/25R22 needs a 22" wheel and 295/30R21 a 21" wheel. This is a plus/minus-size swap that changes wheels too.