TireSizesFinder

245/50R19 vs 275/40R20

275/40R20 is 0.02 in (0.4 mm) taller than 245/50R19, a +0.05% diameter difference. With the speedometer set for 245/50R19, an indicated 60 mph is 60.0 mph on 275/40R20.

Is this a safe swap?

Diameter difference +0.05%: under 1%

By overall diameter alone, 275/40R20 is a near match for 245/50R19; 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: 245/50R19 (28.65 in) vs 275/40R20 (28.66 in)245/50R1928.65 in × 9.65 in275/40R2028.66 in × 10.83 in
Side profile and tread width, drawn to the same scale.
245/50R19 vs 275/40R20 differences
Measurement245/50R19275/40R20Difference% diff
Overall diameter28.65 in (727.6 mm)28.66 in (728.0 mm)+0.02 in (+0.4 mm)+0.05%
Sidewall height4.82 in (122.5 mm)4.33 in (110.0 mm)−0.49 in (−12.5 mm)−10.20%
Section width9.65 in (245.0 mm)10.83 in (275.0 mm)+1.18 in (+30.0 mm)+12.24%
Circumference89.99 in (2,285.8 mm)90.04 in (2,287.1 mm)+0.05 in (+1.3 mm)+0.05%
Revolutions per mile7047040−0.05%
True speed with the speedometer calibrated for 245/50R19
IndicatedActual on 245/50R19Actual on 275/40R20Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.0 mph0.0 mph

Ride-height change: 275/40R20 raises the vehicle by 0.01 in (0.2 mm) at the axle (half the +0.4 mm diameter difference).

275/40R20 is 0.02 in taller than 245/50R19 and 30 mm wider, a 0.05% difference in overall diameter.

With the speedometer calibrated for 245/50R19, an indicated 60 mph is actually 60.0 mph on 275/40R20, and revolutions per mile change from 704 to 704.

275/40R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 245/50R19.

Size pages

Other comparisons with 245/50R19

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