TireSizesFinder

165/80R13 vs 185/55R15

185/55R15 is 0.38 in (9.7 mm) shorter than 165/80R13, a −1.63% diameter difference. With the speedometer set for 165/80R13, an indicated 60 mph is 59.0 mph on 185/55R15.

Is this a safe swap?

Diameter difference −1.63%: within the ±3% guideline

By overall diameter alone, 185/55R15 falls inside the ±3% range commonly used as a guideline when replacing 165/80R13. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 165/80R13 (23.39 in) vs 185/55R15 (23.01 in)165/80R1323.39 in × 6.50 in185/55R1523.01 in × 7.28 in
Side profile and tread width, drawn to the same scale.
165/80R13 vs 185/55R15 differences
Measurement165/80R13185/55R15Difference% diff
Overall diameter23.39 in (594.2 mm)23.01 in (584.5 mm)−0.38 in (−9.7 mm)−1.63%
Sidewall height5.20 in (132.0 mm)4.01 in (101.8 mm)−1.19 in (−30.2 mm)−22.92%
Section width6.50 in (165.0 mm)7.28 in (185.0 mm)+0.79 in (+20.0 mm)+12.12%
Circumference73.49 in (1,866.7 mm)72.29 in (1,836.3 mm)−1.20 in (−30.5 mm)−1.63%
Revolutions per mile862876+14+1.66%
True speed with the speedometer calibrated for 165/80R13
IndicatedActual on 165/80R13Actual on 185/55R15Difference
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: 185/55R15 lowers the vehicle by 0.19 in (4.9 mm) at the axle (half the −9.7 mm diameter difference).

185/55R15 is 0.38 in shorter than 165/80R13 and 20 mm wider, a 1.63% difference in overall diameter.

With the speedometer calibrated for 165/80R13, an indicated 60 mph is actually 59.0 mph on 185/55R15, and revolutions per mile change from 862 to 876.

185/55R15 mounts on a 15-inch wheel, a plus-2 fitment from the 13-inch wheel of 165/80R13.

Size pages

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