185/65R14 vs 175/70R14
175/70R14 is a safe swap for 185/65R14 by the usual ±3% rule: the diameter differs by +0.75%.
Speedometer and odometer
With 175/70R14 on a car calibrated for 185/65R14, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.5 mph |
| 70 mph | 70.5 mph |
| 80 mph | 80.6 mph |
Other sizes close to 185/65R14
Questions
Can I replace 185/65R14 with 175/70R14?
175/70R14 is a safe swap for 185/65R14 by the usual ±3% rule: the diameter differs by +0.75%.
What's the difference between 185/65R14 and 175/70R14?
175/70R14 is 0.18" taller and 10 mm narrower; the sidewall is +0.09". At an indicated 60 mph you'd actually be doing 60.5 mph.
Will 175/70R14 fit on 185/65R14 wheels?
Both use a 14" rim, so the wheel diameter matches; check the wheel's width range for a 175 mm tire and the fender clearance.