265/45R20 vs 295/35R21

295/35R21 is 0.26 in (6.6 mm) shorter than 265/45R20, a −0.88% diameter difference. With the speedometer set for 265/45R20, an indicated 60 mph is 59.5 mph on 295/35R21.

Is this a safe swap?

Diameter difference −0.88%: under 1%

By overall diameter alone, 295/35R21 is a near match for 265/45R20; 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.

265/45R20 vs 295/35R21 differences
Measurement	265/45R20	295/35R21	Difference	% diff
Overall diameter	29.39 in (746.5 mm)	29.13 in (739.9 mm)	−0.26 in (−6.6 mm)	−0.88%
Sidewall height	4.69 in (119.3 mm)	4.06 in (103.3 mm)	−0.63 in (−16.0 mm)	−13.42%
Section width	10.43 in (265.0 mm)	11.61 in (295.0 mm)	+1.18 in (+30.0 mm)	+11.32%
Circumference	92.33 in (2,345.2 mm)	91.51 in (2,324.5 mm)	−0.82 in (−20.7 mm)	−0.88%
Revolutions per mile	686	692	+6	+0.89%

True speed with the speedometer calibrated for 265/45R20
Indicated	Actual on 265/45R20	Actual on 295/35R21	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.5 mph	−0.5 mph
75 mph	75.0 mph	74.3 mph	−0.7 mph

Ride-height change: 295/35R21 lowers the vehicle by 0.13 in (3.3 mm) at the axle (half the −6.6 mm diameter difference).

295/35R21 is 0.26 in shorter than 265/45R20 and 30 mm wider, a 0.88% difference in overall diameter.

With the speedometer calibrated for 265/45R20, an indicated 60 mph is actually 59.5 mph on 295/35R21, and revolutions per mile change from 686 to 692.

295/35R21 mounts on a 21-inch wheel, a plus-1 fitment from the 20-inch wheel of 265/45R20.

Size pages

Other comparisons with 265/45R20

Other comparisons with 295/35R21

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