245/45R16 vs 245/40R17
245/40R17 is a safe swap for 245/45R16 by the usual ±3% rule: the diameter differs by +0.14%.
Speedometer and odometer
With 245/40R17 on a car calibrated for 245/45R16, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.0 mph |
| 45 mph | 45.1 mph |
| 60 mph | 60.1 mph |
| 70 mph | 70.1 mph |
| 80 mph | 80.1 mph |
Other sizes close to 245/45R16
- 245/45R16 vs 205/55R16+0.80%
- 245/45R16 vs 215/45R17-0.26%
- 245/45R16 vs 215/55R16+2.55%
- 245/45R16 vs 205/60R16+4.07%
- 245/45R16 vs 185/65R15-0.86%
- 245/45R16 vs 195/55R16-0.96%
- 245/45R16 vs 225/50R16+0.72%
- 245/45R16 vs 205/50R16-2.47%
- 245/45R16 vs 225/55R16+4.31%
- 245/45R16 vs 195/50R16-4.07%
- 245/45R16 vs 205/60R15+0.02%
- 245/45R16 vs 185/55R16-2.71%
Questions
Can I replace 245/45R16 with 245/40R17?
245/40R17 is a safe swap for 245/45R16 by the usual ±3% rule: the diameter differs by +0.14%.
What's the difference between 245/45R16 and 245/40R17?
245/40R17 is 0.04" taller and 0 mm wider; the sidewall is -0.48". At an indicated 60 mph you'd actually be doing 60.1 mph.
Will 245/40R17 fit on 245/45R16 wheels?
No — 245/45R16 needs a 16" wheel and 245/40R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.