TireSizesFinder

285/30R19 vs 225/30R20

225/30R20 is 0.42 in (10.6 mm) shorter than 285/30R19, a −1.62% diameter difference. With the speedometer set for 285/30R19, an indicated 60 mph is 59.0 mph on 225/30R20.

Is this a safe swap?

Diameter difference −1.62%: within the ±3% guideline

By overall diameter alone, 225/30R20 falls inside the ±3% range commonly used as a guideline when replacing 285/30R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 285/30R19 (25.73 in) vs 225/30R20 (25.31 in)285/30R1925.73 in × 11.22 in225/30R2025.31 in × 8.86 in
Side profile and tread width, drawn to the same scale.
285/30R19 vs 225/30R20 differences
Measurement285/30R19225/30R20Difference% diff
Overall diameter25.73 in (653.6 mm)25.31 in (643.0 mm)−0.42 in (−10.6 mm)−1.62%
Sidewall height3.37 in (85.5 mm)2.66 in (67.5 mm)−0.71 in (−18.0 mm)−21.05%
Section width11.22 in (285.0 mm)8.86 in (225.0 mm)−2.36 in (−60.0 mm)−21.05%
Circumference80.84 in (2,053.3 mm)79.53 in (2,020.0 mm)−1.31 in (−33.3 mm)−1.62%
Revolutions per mile784797+13+1.65%
True speed with the speedometer calibrated for 285/30R19
IndicatedActual on 285/30R19Actual on 225/30R20Difference
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: 225/30R20 lowers the vehicle by 0.21 in (5.3 mm) at the axle (half the −10.6 mm diameter difference).

225/30R20 is 0.42 in shorter than 285/30R19 and 60 mm narrower, a 1.62% difference in overall diameter.

With the speedometer calibrated for 285/30R19, an indicated 60 mph is actually 59.0 mph on 225/30R20, and revolutions per mile change from 784 to 797.

225/30R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 285/30R19.

Size pages

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