TireSizesFinder

225/45R19 vs 285/30R20

285/30R20 is 0.24 in (6.1 mm) shorter than 225/45R19, a −0.89% diameter difference. With the speedometer set for 225/45R19, an indicated 60 mph is 59.5 mph on 285/30R20.

Is this a safe swap?

Diameter difference −0.89%: under 1%

By overall diameter alone, 285/30R20 is a near match for 225/45R19; 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: 225/45R19 (26.97 in) vs 285/30R20 (26.73 in)225/45R1926.97 in × 8.86 in285/30R2026.73 in × 11.22 in
Side profile and tread width, drawn to the same scale.
225/45R19 vs 285/30R20 differences
Measurement225/45R19285/30R20Difference% diff
Overall diameter26.97 in (685.1 mm)26.73 in (679.0 mm)−0.24 in (−6.1 mm)−0.89%
Sidewall height3.99 in (101.3 mm)3.37 in (85.5 mm)−0.62 in (−15.7 mm)−15.56%
Section width8.86 in (225.0 mm)11.22 in (285.0 mm)+2.36 in (+60.0 mm)+26.67%
Circumference84.74 in (2,152.3 mm)83.98 in (2,133.1 mm)−0.75 in (−19.2 mm)−0.89%
Revolutions per mile748754+7+0.90%
True speed with the speedometer calibrated for 225/45R19
IndicatedActual on 225/45R19Actual on 285/30R20Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.5 mph−0.5 mph
75 mph75.0 mph74.3 mph−0.7 mph

Ride-height change: 285/30R20 lowers the vehicle by 0.12 in (3.0 mm) at the axle (half the −6.1 mm diameter difference).

285/30R20 is 0.24 in shorter than 225/45R19 and 60 mm wider, a 0.89% difference in overall diameter.

With the speedometer calibrated for 225/45R19, an indicated 60 mph is actually 59.5 mph on 285/30R20, and revolutions per mile change from 748 to 754.

285/30R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 225/45R19.

Size pages

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