255/60R19 vs 265/50R21

265/50R21 is 0.39 in (9.8 mm) taller than 255/60R19, a +1.24% diameter difference. With the speedometer set for 255/60R19, an indicated 60 mph is 60.7 mph on 265/50R21.

Is this a safe swap?

Diameter difference +1.24%: within the ±3% guideline

By overall diameter alone, 265/50R21 falls inside the ±3% range commonly used as a guideline when replacing 255/60R19. 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.

255/60R19 vs 265/50R21 differences
Measurement	255/60R19	265/50R21	Difference	% diff
Overall diameter	31.05 in (788.6 mm)	31.43 in (798.4 mm)	+0.39 in (+9.8 mm)	+1.24%
Sidewall height	6.02 in (153.0 mm)	5.22 in (132.5 mm)	−0.81 in (−20.5 mm)	−13.40%
Section width	10.04 in (255.0 mm)	10.43 in (265.0 mm)	+0.39 in (+10.0 mm)	+3.92%
Circumference	97.54 in (2,477.5 mm)	98.75 in (2,508.2 mm)	+1.21 in (+30.8 mm)	+1.24%
Revolutions per mile	650	642	−8	−1.23%

True speed with the speedometer calibrated for 255/60R19
Indicated	Actual on 255/60R19	Actual on 265/50R21	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.7 mph	+0.7 mph
75 mph	75.0 mph	75.9 mph	+0.9 mph

Ride-height change: 265/50R21 raises the vehicle by 0.19 in (4.9 mm) at the axle (half the +9.8 mm diameter difference).

265/50R21 is 0.39 in taller than 255/60R19 and 10 mm wider, a 1.24% difference in overall diameter.

With the speedometer calibrated for 255/60R19, an indicated 60 mph is actually 60.7 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 255/60R19.

Size pages

Other comparisons with 255/60R19

Other comparisons with 265/50R21

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