TireSizesFinder

205/65R16 vs 215/50R18

215/50R18 is 0.03 in (0.7 mm) shorter than 205/65R16, a −0.10% diameter difference. With the speedometer set for 205/65R16, an indicated 60 mph is 59.9 mph on 215/50R18.

Is this a safe swap?

Diameter difference −0.10%: under 1%

By overall diameter alone, 215/50R18 is a near match for 205/65R16; 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: 205/65R16 (26.49 in) vs 215/50R18 (26.46 in)205/65R1626.49 in × 8.07 in215/50R1826.46 in × 8.46 in
Side profile and tread width, drawn to the same scale.
205/65R16 vs 215/50R18 differences
Measurement205/65R16215/50R18Difference% diff
Overall diameter26.49 in (672.9 mm)26.46 in (672.2 mm)−0.03 in (−0.7 mm)−0.10%
Sidewall height5.25 in (133.3 mm)4.23 in (107.5 mm)−1.01 in (−25.7 mm)−19.32%
Section width8.07 in (205.0 mm)8.46 in (215.0 mm)+0.39 in (+10.0 mm)+4.88%
Circumference83.23 in (2,114.0 mm)83.14 in (2,111.8 mm)−0.09 in (−2.2 mm)−0.10%
Revolutions per mile761762+1+0.10%
True speed with the speedometer calibrated for 205/65R16
IndicatedActual on 205/65R16Actual on 215/50R18Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 215/50R18 lowers the vehicle by 0.01 in (0.3 mm) at the axle (half the −0.7 mm diameter difference).

215/50R18 is 0.03 in shorter than 205/65R16 and 10 mm wider, a 0.10% difference in overall diameter.

With the speedometer calibrated for 205/65R16, an indicated 60 mph is actually 59.9 mph on 215/50R18, and revolutions per mile change from 761 to 762.

215/50R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 205/65R16.

Size pages

Other comparisons with 205/65R16

Other comparisons with 215/50R18

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