245/45R19 vs 295/30R21

295/30R21 is 0.29 in (7.3 mm) taller than 245/45R19, a +1.04% diameter difference. With the speedometer set for 245/45R19, an indicated 60 mph is 60.6 mph on 295/30R21.

Is this a safe swap?

Diameter difference +1.04%: within the ±3% guideline

By overall diameter alone, 295/30R21 falls inside the ±3% range commonly used as a guideline when replacing 245/45R19. 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.

245/45R19 vs 295/30R21 differences
Measurement	245/45R19	295/30R21	Difference	% diff
Overall diameter	27.68 in (703.1 mm)	27.97 in (710.4 mm)	+0.29 in (+7.3 mm)	+1.04%
Sidewall height	4.34 in (110.3 mm)	3.48 in (88.5 mm)	−0.86 in (−21.7 mm)	−19.73%
Section width	9.65 in (245.0 mm)	11.61 in (295.0 mm)	+1.97 in (+50.0 mm)	+20.41%
Circumference	86.96 in (2,208.9 mm)	87.87 in (2,231.8 mm)	+0.90 in (+22.9 mm)	+1.04%
Revolutions per mile	729	721	−7	−1.03%

True speed with the speedometer calibrated for 245/45R19
Indicated	Actual on 245/45R19	Actual on 295/30R21	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.6 mph	+0.6 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 295/30R21 raises the vehicle by 0.14 in (3.7 mm) at the axle (half the +7.3 mm diameter difference).

295/30R21 is 0.29 in taller than 245/45R19 and 50 mm wider, a 1.04% difference in overall diameter.

With the speedometer calibrated for 245/45R19, an indicated 60 mph is actually 60.6 mph on 295/30R21, and revolutions per mile change from 729 to 721.

295/30R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 245/45R19.

Size pages

Other comparisons with 245/45R19

Other comparisons with 295/30R21

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