TireSizesFinder

205/55R15 vs 185/55R16

185/55R16 is 0.13 in (3.4 mm) taller than 205/55R15, a +0.56% diameter difference. With the speedometer set for 205/55R15, an indicated 60 mph is 60.3 mph on 185/55R16.

Is this a safe swap?

Diameter difference +0.56%: under 1%

By overall diameter alone, 185/55R16 is a near match for 205/55R15; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 205/55R15 (23.88 in) vs 185/55R16 (24.01 in)205/55R1523.88 in × 8.07 in185/55R1624.01 in × 7.28 in
Side profile and tread width, drawn to the same scale.
205/55R15 vs 185/55R16 differences
Measurement205/55R15185/55R16Difference% diff
Overall diameter23.88 in (606.5 mm)24.01 in (609.9 mm)+0.13 in (+3.4 mm)+0.56%
Sidewall height4.44 in (112.8 mm)4.01 in (101.8 mm)−0.43 in (−11.0 mm)−9.76%
Section width8.07 in (205.0 mm)7.28 in (185.0 mm)−0.79 in (−20.0 mm)−9.76%
Circumference75.01 in (1,905.4 mm)75.44 in (1,916.1 mm)+0.42 in (+10.7 mm)+0.56%
Revolutions per mile845840−5−0.56%
True speed with the speedometer calibrated for 205/55R15
IndicatedActual on 205/55R15Actual on 185/55R16Difference
30 mph30.0 mph30.2 mph+0.2 mph
60 mph60.0 mph60.3 mph+0.3 mph
75 mph75.0 mph75.4 mph+0.4 mph

Ride-height change: 185/55R16 raises the vehicle by 0.07 in (1.7 mm) at the axle (half the +3.4 mm diameter difference).

185/55R16 is 0.13 in taller than 205/55R15 and 20 mm narrower, a 0.56% difference in overall diameter.

With the speedometer calibrated for 205/55R15, an indicated 60 mph is actually 60.3 mph on 185/55R16, and revolutions per mile change from 845 to 840.

185/55R16 mounts on a 16-inch wheel, a plus-1 fitment from the 15-inch wheel of 205/55R15.

Size pages

Other comparisons with 205/55R15

Other comparisons with 185/55R16

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