TireSizesFinder

165/70R14 vs 175/55R15

175/55R15 is 0.52 in (13.1 mm) shorter than 165/70R14, a −2.23% diameter difference. With the speedometer set for 165/70R14, an indicated 60 mph is 58.7 mph on 175/55R15.

Is this a safe swap?

Diameter difference −2.23%: within the ±3% guideline

By overall diameter alone, 175/55R15 falls inside the ±3% range commonly used as a guideline when replacing 165/70R14. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 165/70R14 (23.09 in) vs 175/55R15 (22.58 in)165/70R1423.09 in × 6.50 in175/55R1522.58 in × 6.89 in
Side profile and tread width, drawn to the same scale.
165/70R14 vs 175/55R15 differences
Measurement165/70R14175/55R15Difference% diff
Overall diameter23.09 in (586.6 mm)22.58 in (573.5 mm)−0.52 in (−13.1 mm)−2.23%
Sidewall height4.55 in (115.5 mm)3.79 in (96.3 mm)−0.76 in (−19.2 mm)−16.67%
Section width6.50 in (165.0 mm)6.89 in (175.0 mm)+0.39 in (+10.0 mm)+6.06%
Circumference72.55 in (1,842.9 mm)70.93 in (1,801.7 mm)−1.62 in (−41.2 mm)−2.23%
Revolutions per mile873893+20+2.28%
True speed with the speedometer calibrated for 165/70R14
IndicatedActual on 165/70R14Actual on 175/55R15Difference
30 mph30.0 mph29.3 mph−0.7 mph
60 mph60.0 mph58.7 mph−1.3 mph
75 mph75.0 mph73.3 mph−1.7 mph

Ride-height change: 175/55R15 lowers the vehicle by 0.26 in (6.5 mm) at the axle (half the −13.1 mm diameter difference).

175/55R15 is 0.52 in shorter than 165/70R14 and 10 mm wider, a 2.23% difference in overall diameter.

With the speedometer calibrated for 165/70R14, an indicated 60 mph is actually 58.7 mph on 175/55R15, and revolutions per mile change from 873 to 893.

175/55R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 165/70R14.

Size pages

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