CarSpecsHQ

175/65R14 vs 185/55R15

185/55R15 is a safe swap for 175/65R14 by the usual ±3% rule: the diameter differs by +0.24%.

14" → 15"
175/65R14 22.96" · 185/55R15 23.01" · drawn to scale

Side by side

175/65R14185/55R15Difference
Overall diameter22.96"23.01"+0.06" (+0.24%)
Section width175 mm185 mm+10 mm
Sidewall4.48"4.01"-0.47"
Rim14"15"+1"
Circumference72.1"72.3"+0.2"
Revs per mile879876-2
Ride height——+0.03"
Speedometer reads 60 mph60.060.1+0.1 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.1 mph

With 185/55R15 on a car calibrated for 175/65R14, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.2%.

Speedo showsActual speed
30 mph30.1 mph
45 mph45.1 mph
60 mph60.1 mph
70 mph70.2 mph
80 mph80.2 mph

Other sizes close to 175/65R14

Questions

Can I replace 175/65R14 with 185/55R15?

185/55R15 is a safe swap for 175/65R14 by the usual ±3% rule: the diameter differs by +0.24%.

What's the difference between 175/65R14 and 185/55R15?

185/55R15 is 0.06" taller and 10 mm wider; the sidewall is -0.47". At an indicated 60 mph you'd actually be doing 60.1 mph.

Will 185/55R15 fit on 175/65R14 wheels?

No — 175/65R14 needs a 14" wheel and 185/55R15 a 15" wheel. This is a plus/minus-size swap that changes wheels too.