TireSizesFinder

235/35R19 vs 225/30R20

225/30R20 is 0.16 in (4.1 mm) shorter than 235/35R19, a −0.63% diameter difference. With the speedometer set for 235/35R19, an indicated 60 mph is 59.6 mph on 225/30R20.

Is this a safe swap?

Diameter difference −0.63%: under 1%

By overall diameter alone, 225/30R20 is a near match for 235/35R19; 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: 235/35R19 (25.48 in) vs 225/30R20 (25.31 in)235/35R1925.48 in × 9.25 in225/30R2025.31 in × 8.86 in
Side profile and tread width, drawn to the same scale.
235/35R19 vs 225/30R20 differences
Measurement235/35R19225/30R20Difference% diff
Overall diameter25.48 in (647.1 mm)25.31 in (643.0 mm)−0.16 in (−4.1 mm)−0.63%
Sidewall height3.24 in (82.3 mm)2.66 in (67.5 mm)−0.58 in (−14.7 mm)−17.93%
Section width9.25 in (235.0 mm)8.86 in (225.0 mm)−0.39 in (−10.0 mm)−4.26%
Circumference80.04 in (2,032.9 mm)79.53 in (2,020.0 mm)−0.51 in (−12.9 mm)−0.63%
Revolutions per mile792797+5+0.64%
True speed with the speedometer calibrated for 235/35R19
IndicatedActual on 235/35R19Actual 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 0.08 in (2.0 mm) at the axle (half the −4.1 mm diameter difference).

225/30R20 is 0.16 in shorter than 235/35R19 and 10 mm narrower, a 0.63% difference in overall diameter.

With the speedometer calibrated for 235/35R19, an indicated 60 mph is actually 59.6 mph on 225/30R20, and revolutions per mile change from 792 to 797.

225/30R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 235/35R19.

Size pages

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Other comparisons with 225/30R20

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