175/70R14 vs 185/70R14
185/70R14 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +2.33%.
Speedometer and odometer
With 185/70R14 on a car calibrated for 175/70R14, the speedometer reads 58.6 mph when you're really doing 60, and the odometer under-counts by 2.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.7 mph |
| 45 mph | 46.0 mph |
| 60 mph | 61.4 mph |
| 70 mph | 71.6 mph |
| 80 mph | 81.9 mph |
Other sizes close to 175/70R14
Questions
Can I replace 175/70R14 with 185/70R14?
185/70R14 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +2.33%.
What's the difference between 175/70R14 and 185/70R14?
185/70R14 is 0.55" taller and 10 mm wider; the sidewall is +0.28". At an indicated 60 mph you'd actually be doing 61.4 mph.
Will 185/70R14 fit on 175/70R14 wheels?
Both use a 14" rim, so the wheel diameter matches; check the wheel's width range for a 185 mm tire and the fender clearance.