295/35R20 vs 265/40R20

265/40R20 is 0.22 in (5.5 mm) taller than 295/35R20, a +0.77% diameter difference. With the speedometer set for 295/35R20, an indicated 60 mph is 60.5 mph on 265/40R20.

Is this a safe swap?

Diameter difference +0.77%: under 1%

By overall diameter alone, 265/40R20 is a near match for 295/35R20; 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.

295/35R20 vs 265/40R20 differences
Measurement	295/35R20	265/40R20	Difference	% diff
Overall diameter	28.13 in (714.5 mm)	28.35 in (720.0 mm)	+0.22 in (+5.5 mm)	+0.77%
Sidewall height	4.06 in (103.3 mm)	4.17 in (106.0 mm)	+0.11 in (+2.8 mm)	+2.66%
Section width	11.61 in (295.0 mm)	10.43 in (265.0 mm)	−1.18 in (−30.0 mm)	−10.17%
Circumference	88.37 in (2,244.7 mm)	89.05 in (2,261.9 mm)	+0.68 in (+17.3 mm)	+0.77%
Revolutions per mile	717	711	−5	−0.76%

True speed with the speedometer calibrated for 295/35R20
Indicated	Actual on 295/35R20	Actual on 265/40R20	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.6 mph	+0.6 mph

Ride-height change: 265/40R20 raises the vehicle by 0.11 in (2.8 mm) at the axle (half the +5.5 mm diameter difference).

265/40R20 is 0.22 in taller than 295/35R20 and 30 mm narrower, a 0.77% difference in overall diameter.

With the speedometer calibrated for 295/35R20, an indicated 60 mph is actually 60.5 mph on 265/40R20, and revolutions per mile change from 717 to 711.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 295/35R20

Other comparisons with 265/40R20

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