TireSizesFinder

265/50R19 vs 265/40R21

265/40R21 is 0.09 in (2.2 mm) shorter than 265/50R19, a −0.29% diameter difference. With the speedometer set for 265/50R19, an indicated 60 mph is 59.8 mph on 265/40R21.

Is this a safe swap?

Diameter difference −0.29%: under 1%

By overall diameter alone, 265/40R21 is a near match for 265/50R19; 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: 265/50R19 (29.43 in) vs 265/40R21 (29.35 in)265/50R1929.43 in × 10.43 in265/40R2129.35 in × 10.43 in
Side profile and tread width, drawn to the same scale.
265/50R19 vs 265/40R21 differences
Measurement265/50R19265/40R21Difference% diff
Overall diameter29.43 in (747.6 mm)29.35 in (745.4 mm)−0.09 in (−2.2 mm)−0.29%
Sidewall height5.22 in (132.5 mm)4.17 in (106.0 mm)−1.04 in (−26.5 mm)−20.00%
Section width10.43 in (265.0 mm)10.43 in (265.0 mm)0.00 in (0.0 mm)0.00%
Circumference92.47 in (2,348.7 mm)92.19 in (2,341.7 mm)−0.27 in (−6.9 mm)−0.29%
Revolutions per mile685687+2+0.30%
True speed with the speedometer calibrated for 265/50R19
IndicatedActual on 265/50R19Actual on 265/40R21Difference
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: 265/40R21 lowers the vehicle by 0.04 in (1.1 mm) at the axle (half the −2.2 mm diameter difference).

265/40R21 is 0.09 in shorter than 265/50R19 and the same width, a 0.29% difference in overall diameter.

With the speedometer calibrated for 265/50R19, an indicated 60 mph is actually 59.8 mph on 265/40R21, and revolutions per mile change from 685 to 687.

265/40R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 265/50R19.

Size pages

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