TireSizesFinder

145/80R13 vs 185/55R15

185/55R15 is 0.88 in (22.3 mm) taller than 145/80R13, a +3.97% diameter difference. With the speedometer set for 145/80R13, an indicated 60 mph is 62.4 mph on 185/55R15.

Is this a safe swap?

Diameter difference +3.97%: outside the ±3% guideline

By overall diameter alone, 185/55R15 falls outside the ±3% range commonly used as a guideline when replacing 145/80R13; speedometer and ride-height changes are larger. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 145/80R13 (22.13 in) vs 185/55R15 (23.01 in)145/80R1322.13 in × 5.71 in185/55R1523.01 in × 7.28 in
Side profile and tread width, drawn to the same scale.
145/80R13 vs 185/55R15 differences
Measurement145/80R13185/55R15Difference% diff
Overall diameter22.13 in (562.2 mm)23.01 in (584.5 mm)+0.88 in (+22.3 mm)+3.97%
Sidewall height4.57 in (116.0 mm)4.01 in (101.8 mm)−0.56 in (−14.2 mm)−12.28%
Section width5.71 in (145.0 mm)7.28 in (185.0 mm)+1.57 in (+40.0 mm)+27.59%
Circumference69.54 in (1,766.2 mm)72.29 in (1,836.3 mm)+2.76 in (+70.1 mm)+3.97%
Revolutions per mile911876−35−3.82%
True speed with the speedometer calibrated for 145/80R13
IndicatedActual on 145/80R13Actual on 185/55R15Difference
30 mph30.0 mph31.2 mph+1.2 mph
60 mph60.0 mph62.4 mph+2.4 mph
75 mph75.0 mph78.0 mph+3.0 mph

Ride-height change: 185/55R15 raises the vehicle by 0.44 in (11.1 mm) at the axle (half the +22.3 mm diameter difference).

185/55R15 is 0.88 in taller than 145/80R13 and 40 mm wider, a 3.97% difference in overall diameter.

With the speedometer calibrated for 145/80R13, an indicated 60 mph is actually 62.4 mph on 185/55R15, and revolutions per mile change from 911 to 876.

185/55R15 mounts on a 15-inch wheel, a plus-2 fitment from the 13-inch wheel of 145/80R13.

Size pages

Other comparisons with 145/80R13

Other comparisons with 185/55R15

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