265/30R20 vs 235/40R19
235/40R19 is a safe swap for 265/30R20 by the usual ±3% rule: the diameter differs by +0.54%.
Speedometer and odometer
With 235/40R19 on a car calibrated for 265/30R20, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.3 mph |
| 70 mph | 70.4 mph |
| 80 mph | 80.4 mph |
Other sizes close to 265/30R20
- 265/30R20 vs 255/35R19-0.88%
- 265/30R20 vs 245/35R20+1.87%
- 265/30R20 vs 255/35R20+2.92%
- 265/30R20 vs 225/40R19-0.66%
- 265/30R20 vs 265/35R19+0.16%
- 265/30R20 vs 285/30R20+1.80%
- 265/30R20 vs 275/30R20+0.90%
- 265/30R20 vs 265/35R20+3.97%
- 265/30R20 vs 235/35R20+0.82%
- 265/30R20 vs 295/30R20+2.70%
- 265/30R20 vs 305/30R20+3.60%
- 265/30R20 vs 305/30R19-0.21%
Questions
Can I replace 265/30R20 with 235/40R19?
235/40R19 is a safe swap for 265/30R20 by the usual ±3% rule: the diameter differs by +0.54%.
What's the difference between 265/30R20 and 235/40R19?
235/40R19 is 0.14" taller and 30 mm narrower; the sidewall is +0.57". At an indicated 60 mph you'd actually be doing 60.3 mph.
Will 235/40R19 fit on 265/30R20 wheels?
No — 265/30R20 needs a 20" wheel and 235/40R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.