275/30R19 vs 235/30R20
235/30R20 is a safe swap for 275/30R19 by the usual ±3% rule: the diameter differs by +0.22%.
Speedometer and odometer
With 235/30R20 on a car calibrated for 275/30R19, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.1 mph |
| 60 mph | 60.1 mph |
| 70 mph | 70.2 mph |
| 80 mph | 80.2 mph |
Other sizes close to 275/30R19
- 275/30R19 vs 245/40R18+0.86%
- 275/30R19 vs 245/40R19+4.79%
- 275/30R19 vs 235/40R18-0.37%
- 275/30R19 vs 235/40R19+3.55%
- 275/30R19 vs 255/35R19+2.08%
- 275/30R19 vs 275/35R19+4.25%
- 275/30R19 vs 245/35R19+1.00%
- 275/30R19 vs 225/40R19+2.32%
- 275/30R19 vs 235/35R19-0.08%
- 275/30R19 vs 275/35R18+0.32%
- 275/30R19 vs 265/35R18-0.76%
- 275/30R19 vs 265/35R19+3.17%
Questions
Can I replace 275/30R19 with 235/30R20?
235/30R20 is a safe swap for 275/30R19 by the usual ±3% rule: the diameter differs by +0.22%.
What's the difference between 275/30R19 and 235/30R20?
235/30R20 is 0.06" taller and 40 mm narrower; the sidewall is -0.47". At an indicated 60 mph you'd actually be doing 60.1 mph.
Will 235/30R20 fit on 275/30R19 wheels?
No — 275/30R19 needs a 19" wheel and 235/30R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.