205/55R16 vs 255/40R17
255/40R17 is a safe swap for 205/55R16 by the usual ±3% rule: the diameter differs by +0.62%.
Speedometer and odometer
With 255/40R17 on a car calibrated for 205/55R16, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.4 mph |
| 70 mph | 70.4 mph |
| 80 mph | 80.5 mph |
Other sizes close to 205/55R16
- 205/55R16 vs 225/45R17+0.38%
- 205/55R16 vs 205/50R17+0.78%
- 205/55R16 vs 215/55R16+1.74%
- 205/55R16 vs 205/60R16+3.24%
- 205/55R16 vs 195/65R15+0.41%
- 205/55R16 vs 245/40R17-0.65%
- 205/55R16 vs 195/55R16-1.74%
- 205/55R16 vs 225/50R16-0.08%
- 205/55R16 vs 205/50R16-3.24%
- 205/55R16 vs 225/55R16+3.48%
- 205/55R16 vs 195/50R16-4.83%
- 205/55R16 vs 205/60R15-0.78%
Questions
Can I replace 205/55R16 with 255/40R17?
255/40R17 is a safe swap for 205/55R16 by the usual ±3% rule: the diameter differs by +0.62%.
What's the difference between 205/55R16 and 255/40R17?
255/40R17 is 0.15" taller and 50 mm wider; the sidewall is -0.42". At an indicated 60 mph you'd actually be doing 60.4 mph.
Will 255/40R17 fit on 205/55R16 wheels?
No — 205/55R16 needs a 16" wheel and 255/40R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.