265/40R19 vs 315/30R20
315/30R20 is a safe swap for 265/40R19 by the usual ±3% rule: the diameter differs by +0.35%.
Speedometer and odometer
With 315/30R20 on a car calibrated for 265/40R19, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.2 mph |
| 70 mph | 70.2 mph |
| 80 mph | 80.3 mph |
Other sizes close to 265/40R19
- 265/40R19 vs 235/50R18-0.35%
- 265/40R19 vs 245/45R19+1.22%
- 265/40R19 vs 245/40R19-2.30%
- 265/40R19 vs 235/40R19-3.46%
- 265/40R19 vs 255/40R19-1.15%
- 265/40R19 vs 255/35R19-4.82%
- 265/40R19 vs 255/45R19+2.52%
- 265/40R19 vs 275/35R19-2.81%
- 265/40R19 vs 275/40R19+1.15%
- 265/40R19 vs 225/40R19-4.61%
- 265/40R19 vs 275/35R20+0.85%
- 265/40R19 vs 225/45R19-1.37%
Questions
Can I replace 265/40R19 with 315/30R20?
315/30R20 is a safe swap for 265/40R19 by the usual ±3% rule: the diameter differs by +0.35%.
What's the difference between 265/40R19 and 315/30R20?
315/30R20 is 0.09" taller and 50 mm wider; the sidewall is -0.45". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 315/30R20 fit on 265/40R19 wheels?
No — 265/40R19 needs a 19" wheel and 315/30R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.