TireSizesFinder

185/55R15 vs 205/45R16

205/45R16 is 0.25 in (6.4 mm) taller than 185/55R15, a +1.09% diameter difference. With the speedometer set for 185/55R15, an indicated 60 mph is 60.7 mph on 205/45R16.

Is this a safe swap?

Diameter difference +1.09%: within the ±3% guideline

By overall diameter alone, 205/45R16 falls inside the ±3% range commonly used as a guideline when replacing 185/55R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 185/55R15 (23.01 in) vs 205/45R16 (23.26 in)185/55R1523.01 in × 7.28 in205/45R1623.26 in × 8.07 in
Side profile and tread width, drawn to the same scale.
185/55R15 vs 205/45R16 differences
Measurement185/55R15205/45R16Difference% diff
Overall diameter23.01 in (584.5 mm)23.26 in (590.9 mm)+0.25 in (+6.4 mm)+1.09%
Sidewall height4.01 in (101.8 mm)3.63 in (92.3 mm)−0.37 in (−9.5 mm)−9.34%
Section width7.28 in (185.0 mm)8.07 in (205.0 mm)+0.79 in (+20.0 mm)+10.81%
Circumference72.29 in (1,836.3 mm)73.09 in (1,856.4 mm)+0.79 in (+20.1 mm)+1.09%
Revolutions per mile876867−9−1.08%
True speed with the speedometer calibrated for 185/55R15
IndicatedActual on 185/55R15Actual on 205/45R16Difference
30 mph30.0 mph30.3 mph+0.3 mph
60 mph60.0 mph60.7 mph+0.7 mph
75 mph75.0 mph75.8 mph+0.8 mph

Ride-height change: 205/45R16 raises the vehicle by 0.13 in (3.2 mm) at the axle (half the +6.4 mm diameter difference).

205/45R16 is 0.25 in taller than 185/55R15 and 20 mm wider, a 1.09% difference in overall diameter.

With the speedometer calibrated for 185/55R15, an indicated 60 mph is actually 60.7 mph on 205/45R16, and revolutions per mile change from 876 to 867.

205/45R16 mounts on a 16-inch wheel, a plus-1 fitment from the 15-inch wheel of 185/55R15.

Size pages

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