TireSizesFinder

245/35R19 vs 225/30R20

225/30R20 is 0.44 in (11.1 mm) shorter than 245/35R19, a −1.70% diameter difference. With the speedometer set for 245/35R19, an indicated 60 mph is 59.0 mph on 225/30R20.

Is this a safe swap?

Diameter difference −1.70%: within the ±3% guideline

By overall diameter alone, 225/30R20 falls inside the ±3% range commonly used as a guideline when replacing 245/35R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 245/35R19 (25.75 in) vs 225/30R20 (25.31 in)245/35R1925.75 in × 9.65 in225/30R2025.31 in × 8.86 in
Side profile and tread width, drawn to the same scale.
245/35R19 vs 225/30R20 differences
Measurement245/35R19225/30R20Difference% diff
Overall diameter25.75 in (654.1 mm)25.31 in (643.0 mm)−0.44 in (−11.1 mm)−1.70%
Sidewall height3.38 in (85.8 mm)2.66 in (67.5 mm)−0.72 in (−18.2 mm)−21.28%
Section width9.65 in (245.0 mm)8.86 in (225.0 mm)−0.79 in (−20.0 mm)−8.16%
Circumference80.90 in (2,054.9 mm)79.53 in (2,020.0 mm)−1.37 in (−34.9 mm)−1.70%
Revolutions per mile783797+14+1.73%
True speed with the speedometer calibrated for 245/35R19
IndicatedActual on 245/35R19Actual on 225/30R20Difference
30 mph30.0 mph29.5 mph−0.5 mph
60 mph60.0 mph59.0 mph−1.0 mph
75 mph75.0 mph73.7 mph−1.3 mph

Ride-height change: 225/30R20 lowers the vehicle by 0.22 in (5.5 mm) at the axle (half the −11.1 mm diameter difference).

225/30R20 is 0.44 in shorter than 245/35R19 and 20 mm narrower, a 1.70% difference in overall diameter.

With the speedometer calibrated for 245/35R19, an indicated 60 mph is actually 59.0 mph on 225/30R20, and revolutions per mile change from 783 to 797.

225/30R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 245/35R19.

Size pages

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