235/40R19 vs 275/40R18
275/40R18 is a safe swap for 235/40R19 by the usual ±3% rule: the diameter differs by +0.98%.
Speedometer and odometer
With 275/40R18 on a car calibrated for 235/40R19, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.4 mph |
| 60 mph | 60.6 mph |
| 70 mph | 70.7 mph |
| 80 mph | 80.8 mph |
Other sizes close to 235/40R19
- 235/40R19 vs 235/45R18-0.28%
- 235/40R19 vs 245/45R19+4.85%
- 235/40R19 vs 245/40R19+1.19%
- 235/40R19 vs 255/40R19+2.39%
- 235/40R19 vs 255/35R19-1.42%
- 235/40R19 vs 275/35R19+0.67%
- 235/40R19 vs 275/40R19+4.77%
- 235/40R19 vs 245/35R19-2.46%
- 235/40R19 vs 225/40R19-1.19%
- 235/40R19 vs 235/35R19-3.50%
- 235/40R19 vs 225/45R19+2.16%
- 235/40R19 vs 285/35R19+1.71%
Questions
Can I replace 235/40R19 with 275/40R18?
275/40R18 is a safe swap for 235/40R19 by the usual ±3% rule: the diameter differs by +0.98%.
What's the difference between 235/40R19 and 275/40R18?
275/40R18 is 0.26" taller and 40 mm wider; the sidewall is +0.63". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 275/40R18 fit on 235/40R19 wheels?
No — 235/40R19 needs a 19" wheel and 275/40R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.