345/30R19 vs 265/45R18
265/45R18 is a safe swap for 345/30R19 by the usual ±3% rule: the diameter differs by +0.88%.
Speedometer and odometer
With 265/45R18 on a car calibrated for 345/30R19, 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 345/30R19
- 345/30R19 vs 235/50R18+0.38%
- 345/30R19 vs 245/45R19+1.96%
- 345/30R19 vs 245/40R19-1.60%
- 345/30R19 vs 235/40R19-2.76%
- 345/30R19 vs 255/40R19-0.44%
- 345/30R19 vs 255/35R19-4.13%
- 345/30R19 vs 255/45R19+3.26%
- 345/30R19 vs 275/35R19-2.10%
- 345/30R19 vs 275/40R19+1.89%
- 345/30R19 vs 255/35R20-0.45%
- 345/30R19 vs 225/40R19-3.92%
- 345/30R19 vs 225/45R19-0.65%
Questions
Can I replace 345/30R19 with 265/45R18?
265/45R18 is a safe swap for 345/30R19 by the usual ±3% rule: the diameter differs by +0.88%.
What's the difference between 345/30R19 and 265/45R18?
265/45R18 is 0.24" taller and 80 mm narrower; the sidewall is +0.62". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 265/45R18 fit on 345/30R19 wheels?
No — 345/30R19 needs a 19" wheel and 265/45R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.