175/65R15 vs 185/65R15
185/65R15 is a safe swap for 175/65R15 by the usual ±3% rule: the diameter differs by +2.14%.
Speedometer and odometer
With 185/65R15 on a car calibrated for 175/65R15, the speedometer reads 58.7 mph when you're really doing 60, and the odometer under-counts by 2.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.6 mph |
| 45 mph | 46.0 mph |
| 60 mph | 61.3 mph |
| 70 mph | 71.5 mph |
| 80 mph | 81.7 mph |
Other sizes close to 175/65R15
- 175/65R15 vs 195/65R15+4.27%
- 175/65R15 vs 185/60R15-0.90%
- 175/65R15 vs 195/60R15+1.07%
- 175/65R15 vs 205/50R16+0.48%
- 175/65R15 vs 205/50R15-3.70%
- 175/65R15 vs 195/55R15-2.14%
- 175/65R15 vs 205/60R15+3.04%
- 175/65R15 vs 185/55R15-3.94%
- 175/65R15 vs 185/55R16+0.23%
- 175/65R15 vs 225/45R15-4.11%
- 175/65R15 vs 225/50R15-0.41%
Questions
Can I replace 175/65R15 with 185/65R15?
185/65R15 is a safe swap for 175/65R15 by the usual ±3% rule: the diameter differs by +2.14%.
What's the difference between 175/65R15 and 185/65R15?
185/65R15 is 0.51" taller and 10 mm wider; the sidewall is +0.26". At an indicated 60 mph you'd actually be doing 61.3 mph.
Will 185/65R15 fit on 175/65R15 wheels?
Both use a 15" rim, so the wheel diameter matches; check the wheel's width range for a 185 mm tire and the fender clearance.