TireSizesFinder

175/65R14 vs 185/55R15

185/55R15 is 0.06 in (1.4 mm) taller than 175/65R14, a +0.24% diameter difference. With the speedometer set for 175/65R14, an indicated 60 mph is 60.1 mph on 185/55R15.

Is this a safe swap?

Diameter difference +0.24%: under 1%

By overall diameter alone, 185/55R15 is a near match for 175/65R14; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 175/65R14 (22.96 in) vs 185/55R15 (23.01 in)175/65R1422.96 in × 6.89 in185/55R1523.01 in × 7.28 in
Side profile and tread width, drawn to the same scale.
175/65R14 vs 185/55R15 differences
Measurement175/65R14185/55R15Difference% diff
Overall diameter22.96 in (583.1 mm)23.01 in (584.5 mm)+0.06 in (+1.4 mm)+0.24%
Sidewall height4.48 in (113.8 mm)4.01 in (101.8 mm)−0.47 in (−12.0 mm)−10.55%
Section width6.89 in (175.0 mm)7.28 in (185.0 mm)+0.39 in (+10.0 mm)+5.71%
Circumference72.12 in (1,831.9 mm)72.29 in (1,836.3 mm)+0.17 in (+4.4 mm)+0.24%
Revolutions per mile879876−2−0.24%
True speed with the speedometer calibrated for 175/65R14
IndicatedActual on 175/65R14Actual on 185/55R15Difference
30 mph30.0 mph30.1 mph+0.1 mph
60 mph60.0 mph60.1 mph+0.1 mph
75 mph75.0 mph75.2 mph+0.2 mph

Ride-height change: 185/55R15 raises the vehicle by 0.03 in (0.7 mm) at the axle (half the +1.4 mm diameter difference).

185/55R15 is 0.06 in taller than 175/65R14 and 10 mm wider, a 0.24% difference in overall diameter.

With the speedometer calibrated for 175/65R14, an indicated 60 mph is actually 60.1 mph on 185/55R15, and revolutions per mile change from 879 to 876.

185/55R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 175/65R14.

Size pages

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Other comparisons with 185/55R15

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.