TireSizesFinder

225/55R19 vs 275/40R20

275/40R20 is 0.08 in (2.1 mm) shorter than 225/55R19, a −0.29% diameter difference. With the speedometer set for 225/55R19, an indicated 60 mph is 59.8 mph on 275/40R20.

Is this a safe swap?

Diameter difference −0.29%: under 1%

By overall diameter alone, 275/40R20 is a near match for 225/55R19; 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: 225/55R19 (28.74 in) vs 275/40R20 (28.66 in)225/55R1928.74 in × 8.86 in275/40R2028.66 in × 10.83 in
Side profile and tread width, drawn to the same scale.
225/55R19 vs 275/40R20 differences
Measurement225/55R19275/40R20Difference% diff
Overall diameter28.74 in (730.1 mm)28.66 in (728.0 mm)−0.08 in (−2.1 mm)−0.29%
Sidewall height4.87 in (123.8 mm)4.33 in (110.0 mm)−0.54 in (−13.7 mm)−11.11%
Section width8.86 in (225.0 mm)10.83 in (275.0 mm)+1.97 in (+50.0 mm)+22.22%
Circumference90.30 in (2,293.7 mm)90.04 in (2,287.1 mm)−0.26 in (−6.6 mm)−0.29%
Revolutions per mile702704+2+0.29%
True speed with the speedometer calibrated for 225/55R19
IndicatedActual on 225/55R19Actual on 275/40R20Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.8 mph−0.2 mph

Ride-height change: 275/40R20 lowers the vehicle by 0.04 in (1.0 mm) at the axle (half the −2.1 mm diameter difference).

275/40R20 is 0.08 in shorter than 225/55R19 and 50 mm wider, a 0.29% difference in overall diameter.

With the speedometer calibrated for 225/55R19, an indicated 60 mph is actually 59.8 mph on 275/40R20, and revolutions per mile change from 702 to 704.

275/40R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 225/55R19.

Size pages

Other comparisons with 225/55R19

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