175/70R14 vs 185/60R15
185/60R15 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +0.40%.
Speedometer and odometer
With 185/60R15 on a car calibrated for 175/70R14, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.2 mph |
| 70 mph | 70.3 mph |
| 80 mph | 80.3 mph |
Other sizes close to 175/70R14
Questions
Can I replace 175/70R14 with 185/60R15?
185/60R15 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +0.40%.
What's the difference between 175/70R14 and 185/60R15?
185/60R15 is 0.09" taller and 10 mm wider; the sidewall is -0.45". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 185/60R15 fit on 175/70R14 wheels?
No — 175/70R14 needs a 14" wheel and 185/60R15 a 15" wheel. This is a plus/minus-size swap that changes wheels too.