TireSizesFinder

265/55R19 vs 265/45R21

265/45R21 is 0.09 in (2.2 mm) shorter than 265/55R19, a −0.28% diameter difference. With the speedometer set for 265/55R19, an indicated 60 mph is 59.8 mph on 265/45R21.

Is this a safe swap?

Diameter difference −0.28%: under 1%

By overall diameter alone, 265/45R21 is a near match for 265/55R19; 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: 265/55R19 (30.48 in) vs 265/45R21 (30.39 in)265/55R1930.48 in × 10.43 in265/45R2130.39 in × 10.43 in
Side profile and tread width, drawn to the same scale.
265/55R19 vs 265/45R21 differences
Measurement265/55R19265/45R21Difference% diff
Overall diameter30.48 in (774.1 mm)30.39 in (771.9 mm)−0.09 in (−2.2 mm)−0.28%
Sidewall height5.74 in (145.8 mm)4.69 in (119.3 mm)−1.04 in (−26.5 mm)−18.18%
Section width10.43 in (265.0 mm)10.43 in (265.0 mm)0.00 in (0.0 mm)0.00%
Circumference95.74 in (2,431.9 mm)95.47 in (2,425.0 mm)−0.27 in (−6.9 mm)−0.28%
Revolutions per mile662664+2+0.29%
True speed with the speedometer calibrated for 265/55R19
IndicatedActual on 265/55R19Actual on 265/45R21Difference
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: 265/45R21 lowers the vehicle by 0.04 in (1.1 mm) at the axle (half the −2.2 mm diameter difference).

265/45R21 is 0.09 in shorter than 265/55R19 and the same width, a 0.28% difference in overall diameter.

With the speedometer calibrated for 265/55R19, an indicated 60 mph is actually 59.8 mph on 265/45R21, and revolutions per mile change from 662 to 664.

265/45R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 265/55R19.

Size pages

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