TireSizesFinder

185/65R15 vs 205/50R16

205/50R16 is 0.40 in (10.1 mm) shorter than 185/65R15, a −1.63% diameter difference. With the speedometer set for 185/65R15, an indicated 60 mph is 59.0 mph on 205/50R16.

Is this a safe swap?

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

By overall diameter alone, 205/50R16 falls inside the ±3% range commonly used as a guideline when replacing 185/65R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 185/65R15 (24.47 in) vs 205/50R16 (24.07 in)185/65R1524.47 in × 7.28 in205/50R1624.07 in × 8.07 in
Side profile and tread width, drawn to the same scale.
185/65R15 vs 205/50R16 differences
Measurement185/65R15205/50R16Difference% diff
Overall diameter24.47 in (621.5 mm)24.07 in (611.4 mm)−0.40 in (−10.1 mm)−1.63%
Sidewall height4.73 in (120.3 mm)4.04 in (102.5 mm)−0.70 in (−17.7 mm)−14.76%
Section width7.28 in (185.0 mm)8.07 in (205.0 mm)+0.79 in (+20.0 mm)+10.81%
Circumference76.87 in (1,952.5 mm)75.62 in (1,920.8 mm)−1.25 in (−31.7 mm)−1.63%
Revolutions per mile824838+14+1.65%
True speed with the speedometer calibrated for 185/65R15
IndicatedActual on 185/65R15Actual on 205/50R16Difference
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: 205/50R16 lowers the vehicle by 0.20 in (5.1 mm) at the axle (half the −10.1 mm diameter difference).

205/50R16 is 0.40 in shorter than 185/65R15 and 20 mm wider, a 1.63% difference in overall diameter.

With the speedometer calibrated for 185/65R15, an indicated 60 mph is actually 59.0 mph on 205/50R16, and revolutions per mile change from 824 to 838.

205/50R16 mounts on a 16-inch wheel, a plus-1 fitment from the 15-inch wheel of 185/65R15.

Size pages

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