225/45R19 vs 245/35R20

245/35R20 is 0.22 in (5.6 mm) shorter than 225/45R19, a −0.82% diameter difference. With the speedometer set for 225/45R19, an indicated 60 mph is 59.5 mph on 245/35R20.

Is this a safe swap?

Diameter difference −0.82%: under 1%

By overall diameter alone, 245/35R20 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 245/35R20 (26.75 in)225/45R1926.97 in × 8.86 in245/35R2026.75 in × 9.65 in
Side profile and tread width, drawn to the same scale.
225/45R19 vs 245/35R20 differences
Measurement225/45R19245/35R20Difference% diff
Overall diameter26.97 in (685.1 mm)26.75 in (679.5 mm)−0.22 in (−5.6 mm)−0.82%
Sidewall height3.99 in (101.3 mm)3.38 in (85.8 mm)−0.61 in (−15.5 mm)−15.31%
Section width8.86 in (225.0 mm)9.65 in (245.0 mm)+0.79 in (+20.0 mm)+8.89%
Circumference84.74 in (2,152.3 mm)84.04 in (2,134.7 mm)−0.69 in (−17.6 mm)−0.82%
Revolutions per mile748754+6+0.82%
True speed with the speedometer calibrated for 225/45R19
IndicatedActual on 225/45R19Actual on 245/35R20Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.5 mph−0.5 mph
75 mph75.0 mph74.4 mph−0.6 mph

Ride-height change: 245/35R20 lowers the vehicle by 0.11 in (2.8 mm) at the axle (half the −5.6 mm diameter difference).

245/35R20 is 0.22 in shorter than 225/45R19 and 20 mm wider, a 0.82% difference in overall diameter.

With the speedometer calibrated for 225/45R19, an indicated 60 mph is actually 59.5 mph on 245/35R20, and revolutions per mile change from 748 to 754.

245/35R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 225/45R19.

Size pages

Other comparisons with 225/45R19

Other comparisons with 245/35R20

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