225/40R20 vs 265/35R20

265/35R20 is 0.22 in (5.5 mm) taller than 225/40R20, a +0.80% diameter difference. With the speedometer set for 225/40R20, an indicated 60 mph is 60.5 mph on 265/35R20.

Is this a safe swap?

Diameter difference +0.80%: under 1%

By overall diameter alone, 265/35R20 is a near match for 225/40R20; 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.

225/40R20 vs 265/35R20 differences
Measurement	225/40R20	265/35R20	Difference	% diff
Overall diameter	27.09 in (688.0 mm)	27.30 in (693.5 mm)	+0.22 in (+5.5 mm)	+0.80%
Sidewall height	3.54 in (90.0 mm)	3.65 in (92.8 mm)	+0.11 in (+2.8 mm)	+3.06%
Section width	8.86 in (225.0 mm)	10.43 in (265.0 mm)	+1.57 in (+40.0 mm)	+17.78%
Circumference	85.10 in (2,161.4 mm)	85.78 in (2,178.7 mm)	+0.68 in (+17.3 mm)	+0.80%
Revolutions per mile	745	739	−6	−0.79%

True speed with the speedometer calibrated for 225/40R20
Indicated	Actual on 225/40R20	Actual on 265/35R20	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: 265/35R20 raises the vehicle by 0.11 in (2.8 mm) at the axle (half the +5.5 mm diameter difference).

265/35R20 is 0.22 in taller than 225/40R20 and 40 mm wider, a 0.80% difference in overall diameter.

With the speedometer calibrated for 225/40R20, an indicated 60 mph is actually 60.5 mph on 265/35R20, and revolutions per mile change from 745 to 739.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 225/40R20

Other comparisons with 265/35R20

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