225/45R19 vs 305/30R20
305/30R20 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.86%.
Speedometer and odometer
With 305/30R20 on a car calibrated for 225/45R19, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.9%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.4 mph |
| 60 mph | 60.5 mph |
| 70 mph | 70.6 mph |
| 80 mph | 80.7 mph |
Other sizes close to 225/45R19
- 225/45R19 vs 245/45R19+2.63%
- 225/45R19 vs 245/40R19-0.95%
- 225/45R19 vs 225/50R18-0.42%
- 225/45R19 vs 235/40R19-2.12%
- 225/45R19 vs 255/40R19+0.22%
- 225/45R19 vs 255/35R19-3.50%
- 225/45R19 vs 255/45R19+3.94%
- 225/45R19 vs 275/35R19-1.46%
- 225/45R19 vs 275/40R19+2.55%
- 225/45R19 vs 245/35R20-0.82%
- 225/45R19 vs 245/35R19-4.52%
- 225/45R19 vs 255/35R20+0.20%
Questions
Can I replace 225/45R19 with 305/30R20?
305/30R20 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.86%.
What's the difference between 225/45R19 and 305/30R20?
305/30R20 is 0.23" taller and 80 mm wider; the sidewall is -0.38". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 305/30R20 fit on 225/45R19 wheels?
No — 225/45R19 needs a 19" wheel and 305/30R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.