TireSizesFinder

175/65R14 vs 175/55R15

175/55R15 is 0.38 in (9.6 mm) shorter than 175/65R14, a −1.65% diameter difference. With the speedometer set for 175/65R14, an indicated 60 mph is 59.0 mph on 175/55R15.

Is this a safe swap?

Diameter difference −1.65%: within the ±3% guideline

By overall diameter alone, 175/55R15 falls inside the ±3% range commonly used as a guideline when replacing 175/65R14. 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 175/55R15 (22.58 in)175/65R1422.96 in × 6.89 in175/55R1522.58 in × 6.89 in
Side profile and tread width, drawn to the same scale.
175/65R14 vs 175/55R15 differences
Measurement175/65R14175/55R15Difference% diff
Overall diameter22.96 in (583.1 mm)22.58 in (573.5 mm)−0.38 in (−9.6 mm)−1.65%
Sidewall height4.48 in (113.8 mm)3.79 in (96.3 mm)−0.69 in (−17.5 mm)−15.38%
Section width6.89 in (175.0 mm)6.89 in (175.0 mm)0.00 in (0.0 mm)0.00%
Circumference72.12 in (1,831.9 mm)70.93 in (1,801.7 mm)−1.19 in (−30.2 mm)−1.65%
Revolutions per mile879893+15+1.67%
True speed with the speedometer calibrated for 175/65R14
IndicatedActual on 175/65R14Actual on 175/55R15Difference
30 mph30.0 mph29.5 mph−0.5 mph
60 mph60.0 mph59.0 mph−1.0 mph
75 mph75.0 mph73.8 mph−1.2 mph

Ride-height change: 175/55R15 lowers the vehicle by 0.19 in (4.8 mm) at the axle (half the −9.6 mm diameter difference).

175/55R15 is 0.38 in shorter than 175/65R14 and the same width, a 1.65% difference in overall diameter.

With the speedometer calibrated for 175/65R14, an indicated 60 mph is actually 59.0 mph on 175/55R15, and revolutions per mile change from 879 to 893.

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

Size pages

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