TireSizesFinder

275/30R19 vs 225/30R20

225/30R20 is 0.18 in (4.6 mm) shorter than 275/30R19, a −0.71% diameter difference. With the speedometer set for 275/30R19, an indicated 60 mph is 59.6 mph on 225/30R20.

Is this a safe swap?

Diameter difference −0.71%: under 1%

By overall diameter alone, 225/30R20 is a near match for 275/30R19; 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: 275/30R19 (25.50 in) vs 225/30R20 (25.31 in)275/30R1925.50 in × 10.83 in225/30R2025.31 in × 8.86 in
Side profile and tread width, drawn to the same scale.
275/30R19 vs 225/30R20 differences
Measurement275/30R19225/30R20Difference% diff
Overall diameter25.50 in (647.6 mm)25.31 in (643.0 mm)−0.18 in (−4.6 mm)−0.71%
Sidewall height3.25 in (82.5 mm)2.66 in (67.5 mm)−0.59 in (−15.0 mm)−18.18%
Section width10.83 in (275.0 mm)8.86 in (225.0 mm)−1.97 in (−50.0 mm)−18.18%
Circumference80.10 in (2,034.5 mm)79.53 in (2,020.0 mm)−0.57 in (−14.5 mm)−0.71%
Revolutions per mile791797+6+0.72%
True speed with the speedometer calibrated for 275/30R19
IndicatedActual on 275/30R19Actual on 225/30R20Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.5 mph−0.5 mph

Ride-height change: 225/30R20 lowers the vehicle by 0.09 in (2.3 mm) at the axle (half the −4.6 mm diameter difference).

225/30R20 is 0.18 in shorter than 275/30R19 and 50 mm narrower, a 0.71% difference in overall diameter.

With the speedometer calibrated for 275/30R19, an indicated 60 mph is actually 59.6 mph on 225/30R20, and revolutions per mile change from 791 to 797.

225/30R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 275/30R19.

Size pages

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