TireSizesFinder

275/50R19 vs 285/40R21

285/40R21 is 0.15 in (3.8 mm) taller than 275/50R19, a +0.50% diameter difference. With the speedometer set for 275/50R19, an indicated 60 mph is 60.3 mph on 285/40R21.

Is this a safe swap?

Diameter difference +0.50%: under 1%

By overall diameter alone, 285/40R21 is a near match for 275/50R19; 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: 275/50R19 (29.83 in) vs 285/40R21 (29.98 in)275/50R1929.83 in × 10.83 in285/40R2129.98 in × 11.22 in
Side profile and tread width, drawn to the same scale.
275/50R19 vs 285/40R21 differences
Measurement275/50R19285/40R21Difference% diff
Overall diameter29.83 in (757.6 mm)29.98 in (761.4 mm)+0.15 in (+3.8 mm)+0.50%
Sidewall height5.41 in (137.5 mm)4.49 in (114.0 mm)−0.93 in (−23.5 mm)−17.09%
Section width10.83 in (275.0 mm)11.22 in (285.0 mm)+0.39 in (+10.0 mm)+3.64%
Circumference93.70 in (2,380.1 mm)94.17 in (2,392.0 mm)+0.47 in (+11.9 mm)+0.50%
Revolutions per mile676673−3−0.50%
True speed with the speedometer calibrated for 275/50R19
IndicatedActual on 275/50R19Actual on 285/40R21Difference
30 mph30.0 mph30.2 mph+0.2 mph
60 mph60.0 mph60.3 mph+0.3 mph
75 mph75.0 mph75.4 mph+0.4 mph

Ride-height change: 285/40R21 raises the vehicle by 0.07 in (1.9 mm) at the axle (half the +3.8 mm diameter difference).

285/40R21 is 0.15 in taller than 275/50R19 and 10 mm wider, a 0.50% difference in overall diameter.

With the speedometer calibrated for 275/50R19, an indicated 60 mph is actually 60.3 mph on 285/40R21, and revolutions per mile change from 676 to 673.

285/40R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 275/50R19.

Size pages

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