235/65R19 vs 265/50R21

265/50R21 is 0.41 in (10.3 mm) taller than 235/65R19, a +1.31% diameter difference. With the speedometer set for 235/65R19, an indicated 60 mph is 60.8 mph on 265/50R21.

Is this a safe swap?

Diameter difference +1.31%: within the ±3% guideline

By overall diameter alone, 265/50R21 falls inside the ±3% range commonly used as a guideline when replacing 235/65R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

235/65R19 vs 265/50R21 differences
Measurement	235/65R19	265/50R21	Difference	% diff
Overall diameter	31.03 in (788.1 mm)	31.43 in (798.4 mm)	+0.41 in (+10.3 mm)	+1.31%
Sidewall height	6.01 in (152.8 mm)	5.22 in (132.5 mm)	−0.80 in (−20.2 mm)	−13.26%
Section width	9.25 in (235.0 mm)	10.43 in (265.0 mm)	+1.18 in (+30.0 mm)	+12.77%
Circumference	97.48 in (2,475.9 mm)	98.75 in (2,508.2 mm)	+1.27 in (+32.4 mm)	+1.31%
Revolutions per mile	650	642	−8	−1.29%

True speed with the speedometer calibrated for 235/65R19
Indicated	Actual on 235/65R19	Actual on 265/50R21	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.8 mph	+0.8 mph
75 mph	75.0 mph	76.0 mph	+1.0 mph

Ride-height change: 265/50R21 raises the vehicle by 0.20 in (5.2 mm) at the axle (half the +10.3 mm diameter difference).

265/50R21 is 0.41 in taller than 235/65R19 and 30 mm wider, a 1.31% difference in overall diameter.

With the speedometer calibrated for 235/65R19, an indicated 60 mph is actually 60.8 mph on 265/50R21, and revolutions per mile change from 650 to 642.

265/50R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 235/65R19.

Size pages

Other comparisons with 235/65R19

Other comparisons with 265/50R21

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.