275/45R18 vs 285/40R19
285/40R19 is a safe swap for 275/45R18 by the usual ±3% rule: the diameter differs by +0.84%.
Speedometer and odometer
With 285/40R19 on a car calibrated for 275/45R18, 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 | 30.3 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 275/45R18
- 275/45R18 vs 235/60R18+4.90%
- 275/45R18 vs 245/45R18-3.83%
- 275/45R18 vs 235/50R18-1.77%
- 275/45R18 vs 235/55R18+1.56%
- 275/45R18 vs 245/45R19-0.23%
- 275/45R18 vs 225/60R18+3.19%
- 275/45R18 vs 225/50R18-3.19%
- 275/45R18 vs 225/60R17-0.41%
- 275/45R18 vs 225/55R180.00%
- 275/45R18 vs 255/55R18+4.68%
- 275/45R18 vs 275/40R19-0.30%
- 275/45R18 vs 215/65R17+0.94%
Questions
Can I replace 275/45R18 with 285/40R19?
285/40R19 is a safe swap for 275/45R18 by the usual ±3% rule: the diameter differs by +0.84%.
What's the difference between 275/45R18 and 285/40R19?
285/40R19 is 0.23" taller and 10 mm wider; the sidewall is -0.38". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 285/40R19 fit on 275/45R18 wheels?
No — 275/45R18 needs a 18" wheel and 285/40R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.