235/35R19 vs 245/40R18
245/40R18 is a safe swap for 235/35R19 by the usual ±3% rule: the diameter differs by +0.94%.
Speedometer and odometer
With 245/40R18 on a car calibrated for 235/35R19, the speedometer reads 59.4 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 | 60.6 mph |
| 70 mph | 70.7 mph |
| 80 mph | 80.8 mph |
Other sizes close to 235/35R19
- 235/35R19 vs 245/40R19+4.87%
- 235/35R19 vs 235/40R18-0.29%
- 235/35R19 vs 235/40R19+3.63%
- 235/35R19 vs 255/35R19+2.16%
- 235/35R19 vs 275/35R19+4.33%
- 235/35R19 vs 245/35R19+1.08%
- 235/35R19 vs 225/40R19+2.40%
- 235/35R19 vs 275/35R18+0.40%
- 235/35R19 vs 265/35R18-0.68%
- 235/35R19 vs 265/35R19+3.25%
- 235/35R19 vs 215/45R18+0.56%
- 235/35R19 vs 285/30R19+1.00%
Questions
Can I replace 235/35R19 with 245/40R18?
245/40R18 is a safe swap for 235/35R19 by the usual ±3% rule: the diameter differs by +0.94%.
What's the difference between 235/35R19 and 245/40R18?
245/40R18 is 0.24" taller and 10 mm wider; the sidewall is +0.62". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 245/40R18 fit on 235/35R19 wheels?
No — 235/35R19 needs a 19" wheel and 245/40R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.