295/35R19 vs 275/30R21

275/30R21 is 0.37 in (9.3 mm) taller than 295/35R19, a +1.35% diameter difference. With the speedometer set for 295/35R19, an indicated 60 mph is 60.8 mph on 275/30R21.

Is this a safe swap?

Diameter difference +1.35%: within the ±3% guideline

By overall diameter alone, 275/30R21 falls inside the ±3% range commonly used as a guideline when replacing 295/35R19. 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.

295/35R19 vs 275/30R21 differences
Measurement	295/35R19	275/30R21	Difference	% diff
Overall diameter	27.13 in (689.1 mm)	27.50 in (698.4 mm)	+0.37 in (+9.3 mm)	+1.35%
Sidewall height	4.06 in (103.3 mm)	3.25 in (82.5 mm)	−0.82 in (−20.7 mm)	−20.10%
Section width	11.61 in (295.0 mm)	10.83 in (275.0 mm)	−0.79 in (−20.0 mm)	−6.78%
Circumference	85.23 in (2,164.9 mm)	86.38 in (2,194.1 mm)	+1.15 in (+29.2 mm)	+1.35%
Revolutions per mile	743	733	−10	−1.33%

True speed with the speedometer calibrated for 295/35R19
Indicated	Actual on 295/35R19	Actual on 275/30R21	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: 275/30R21 raises the vehicle by 0.18 in (4.7 mm) at the axle (half the +9.3 mm diameter difference).

275/30R21 is 0.37 in taller than 295/35R19 and 20 mm narrower, a 1.35% difference in overall diameter.

With the speedometer calibrated for 295/35R19, an indicated 60 mph is actually 60.8 mph on 275/30R21, and revolutions per mile change from 743 to 733.

275/30R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 295/35R19.

Size pages

Other comparisons with 295/35R19

Other comparisons with 275/30R21

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