255/50R19 vs 295/35R21

295/35R21 is 0.09 in (2.3 mm) taller than 255/50R19, a +0.31% diameter difference. With the speedometer set for 255/50R19, an indicated 60 mph is 60.2 mph on 295/35R21.

Is this a safe swap?

Diameter difference +0.31%: under 1%

By overall diameter alone, 295/35R21 is a near match for 255/50R19; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

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

255/50R19 vs 295/35R21 differences
Measurement	255/50R19	295/35R21	Difference	% diff
Overall diameter	29.04 in (737.6 mm)	29.13 in (739.9 mm)	+0.09 in (+2.3 mm)	+0.31%
Sidewall height	5.02 in (127.5 mm)	4.06 in (103.3 mm)	−0.95 in (−24.2 mm)	−19.02%
Section width	10.04 in (255.0 mm)	11.61 in (295.0 mm)	+1.57 in (+40.0 mm)	+15.69%
Circumference	91.23 in (2,317.2 mm)	91.51 in (2,324.5 mm)	+0.28 in (+7.2 mm)	+0.31%
Revolutions per mile	695	692	−2	−0.31%

True speed with the speedometer calibrated for 255/50R19
Indicated	Actual on 255/50R19	Actual on 295/35R21	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.2 mph	+0.2 mph
75 mph	75.0 mph	75.2 mph	+0.2 mph

Ride-height change: 295/35R21 raises the vehicle by 0.05 in (1.2 mm) at the axle (half the +2.3 mm diameter difference).

295/35R21 is 0.09 in taller than 255/50R19 and 40 mm wider, a 0.31% difference in overall diameter.

With the speedometer calibrated for 255/50R19, an indicated 60 mph is actually 60.2 mph on 295/35R21, and revolutions per mile change from 695 to 692.

295/35R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 255/50R19.

Size pages

Other comparisons with 255/50R19

Other comparisons with 295/35R21

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