225/35R19 vs 235/40R18
235/40R18 is a safe swap for 225/35R19 by the usual ±3% rule: the diameter differs by +0.80%.
Speedometer and odometer
With 235/40R18 on a car calibrated for 225/35R19, 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 | 30.2 mph |
| 45 mph | 45.4 mph |
| 60 mph | 60.5 mph |
| 70 mph | 70.6 mph |
| 80 mph | 80.6 mph |
Other sizes close to 225/35R19
- 225/35R19 vs 225/40R18-0.45%
- 225/35R19 vs 235/40R19+4.76%
- 225/35R19 vs 255/35R19+3.28%
- 225/35R19 vs 255/35R18-0.69%
- 225/35R19 vs 245/35R19+2.19%
- 225/35R19 vs 225/40R19+3.52%
- 225/35R19 vs 235/35R19+1.09%
- 225/35R19 vs 265/35R18+0.41%
- 225/35R19 vs 265/35R19+4.37%
- 225/35R19 vs 285/30R19+2.11%
- 225/35R19 vs 305/30R19+3.98%
- 225/35R19 vs 255/30R19-0.70%
Questions
Can I replace 225/35R19 with 235/40R18?
235/40R18 is a safe swap for 225/35R19 by the usual ±3% rule: the diameter differs by +0.80%.
What's the difference between 225/35R19 and 235/40R18?
235/40R18 is 0.20" taller and 10 mm wider; the sidewall is +0.60". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 235/40R18 fit on 225/35R19 wheels?
No — 225/35R19 needs a 19" wheel and 235/40R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.