185/60R14 vs 175/55R15

175/55R15 is 0.16 in (4.1 mm) shorter than 185/60R14, a −0.71% diameter difference. With the speedometer set for 185/60R14, an indicated 60 mph is 59.6 mph on 175/55R15.

Is this a safe swap?

Diameter difference −0.71%: under 1%

By overall diameter alone, 175/55R15 is a near match for 185/60R14; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

185/60R14 vs 175/55R15 differences
Measurement	185/60R14	175/55R15	Difference	% diff
Overall diameter	22.74 in (577.6 mm)	22.58 in (573.5 mm)	−0.16 in (−4.1 mm)	−0.71%
Sidewall height	4.37 in (111.0 mm)	3.79 in (96.3 mm)	−0.58 in (−14.7 mm)	−13.29%
Section width	7.28 in (185.0 mm)	6.89 in (175.0 mm)	−0.39 in (−10.0 mm)	−5.41%
Circumference	71.44 in (1,814.6 mm)	70.93 in (1,801.7 mm)	−0.51 in (−12.9 mm)	−0.71%
Revolutions per mile	887	893	+6	+0.71%

True speed with the speedometer calibrated for 185/60R14
Indicated	Actual on 185/60R14	Actual on 175/55R15	Difference
30 mph	30.0 mph	29.8 mph	−0.2 mph
60 mph	60.0 mph	59.6 mph	−0.4 mph
75 mph	75.0 mph	74.5 mph	−0.5 mph

Ride-height change: 175/55R15 lowers the vehicle by 0.08 in (2.0 mm) at the axle (half the −4.1 mm diameter difference).

175/55R15 is 0.16 in shorter than 185/60R14 and 10 mm narrower, a 0.71% difference in overall diameter.

With the speedometer calibrated for 185/60R14, an indicated 60 mph is actually 59.6 mph on 175/55R15, and revolutions per mile change from 887 to 893.

175/55R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 185/60R14.

Size pages

Other comparisons with 185/60R14

Other comparisons with 175/55R15

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.