TireSizesFinder

255/65R16 vs 225/60R18

225/60R18 is 0.42 in (10.7 mm) shorter than 255/65R16, a −1.45% diameter difference. With the speedometer set for 255/65R16, an indicated 60 mph is 59.1 mph on 225/60R18.

Is this a safe swap?

Diameter difference −1.45%: within the ±3% guideline

By overall diameter alone, 225/60R18 falls inside the ±3% range commonly used as a guideline when replacing 255/65R16. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 255/65R16 (29.05 in) vs 225/60R18 (28.63 in)255/65R1629.05 in × 10.04 in225/60R1828.63 in × 8.86 in
Side profile and tread width, drawn to the same scale.
255/65R16 vs 225/60R18 differences
Measurement255/65R16225/60R18Difference% diff
Overall diameter29.05 in (737.9 mm)28.63 in (727.2 mm)−0.42 in (−10.7 mm)−1.45%
Sidewall height6.53 in (165.8 mm)5.31 in (135.0 mm)−1.21 in (−30.7 mm)−18.55%
Section width10.04 in (255.0 mm)8.86 in (225.0 mm)−1.18 in (−30.0 mm)−11.76%
Circumference91.27 in (2,318.2 mm)89.94 in (2,284.6 mm)−1.32 in (−33.6 mm)−1.45%
Revolutions per mile694704+10+1.47%
True speed with the speedometer calibrated for 255/65R16
IndicatedActual on 255/65R16Actual on 225/60R18Difference
30 mph30.0 mph29.6 mph−0.4 mph
60 mph60.0 mph59.1 mph−0.9 mph
75 mph75.0 mph73.9 mph−1.1 mph

Ride-height change: 225/60R18 lowers the vehicle by 0.21 in (5.3 mm) at the axle (half the −10.7 mm diameter difference).

225/60R18 is 0.42 in shorter than 255/65R16 and 30 mm narrower, a 1.45% difference in overall diameter.

With the speedometer calibrated for 255/65R16, an indicated 60 mph is actually 59.1 mph on 225/60R18, and revolutions per mile change from 694 to 704.

225/60R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 255/65R16.

Size pages

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