TireSizesFinder

245/55R20 vs 285/40R22

285/40R22 is 0.37 in (9.3 mm) taller than 245/55R20, a +1.20% diameter difference. With the speedometer set for 245/55R20, an indicated 60 mph is 60.7 mph on 285/40R22.

Is this a safe swap?

Diameter difference +1.20%: within the ±3% guideline

By overall diameter alone, 285/40R22 falls inside the ±3% range commonly used as a guideline when replacing 245/55R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 245/55R20 (30.61 in) vs 285/40R22 (30.98 in)245/55R2030.61 in × 9.65 in285/40R2230.98 in × 11.22 in
Side profile and tread width, drawn to the same scale.
245/55R20 vs 285/40R22 differences
Measurement245/55R20285/40R22Difference% diff
Overall diameter30.61 in (777.5 mm)30.98 in (786.8 mm)+0.37 in (+9.3 mm)+1.20%
Sidewall height5.31 in (134.8 mm)4.49 in (114.0 mm)−0.82 in (−20.7 mm)−15.40%
Section width9.65 in (245.0 mm)11.22 in (285.0 mm)+1.57 in (+40.0 mm)+16.33%
Circumference96.16 in (2,442.6 mm)97.32 in (2,471.8 mm)+1.15 in (+29.2 mm)+1.20%
Revolutions per mile659651−8−1.18%
True speed with the speedometer calibrated for 245/55R20
IndicatedActual on 245/55R20Actual on 285/40R22Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.7 mph+0.7 mph
75 mph75.0 mph75.9 mph+0.9 mph

Ride-height change: 285/40R22 raises the vehicle by 0.18 in (4.6 mm) at the axle (half the +9.3 mm diameter difference).

285/40R22 is 0.37 in taller than 245/55R20 and 40 mm wider, a 1.20% difference in overall diameter.

With the speedometer calibrated for 245/55R20, an indicated 60 mph is actually 60.7 mph on 285/40R22, and revolutions per mile change from 659 to 651.

285/40R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 245/55R20.

Size pages

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