265/70R18 vs 295/55R20

295/55R20 is 0.17 in (4.3 mm) taller than 265/70R18, a +0.52% diameter difference. With the speedometer set for 265/70R18, an indicated 60 mph is 60.3 mph on 295/55R20.

Is this a safe swap?

Diameter difference +0.52%: under 1%

By overall diameter alone, 295/55R20 is a near match for 265/70R18; 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.

265/70R18 vs 295/55R20 differences
Measurement	265/70R18	295/55R20	Difference	% diff
Overall diameter	32.61 in (828.2 mm)	32.78 in (832.5 mm)	+0.17 in (+4.3 mm)	+0.52%
Sidewall height	7.30 in (185.5 mm)	6.39 in (162.3 mm)	−0.92 in (−23.2 mm)	−12.53%
Section width	10.43 in (265.0 mm)	11.61 in (295.0 mm)	+1.18 in (+30.0 mm)	+11.32%
Circumference	102.44 in (2,601.9 mm)	102.97 in (2,615.4 mm)	+0.53 in (+13.5 mm)	+0.52%
Revolutions per mile	619	615	−3	−0.52%

True speed with the speedometer calibrated for 265/70R18
Indicated	Actual on 265/70R18	Actual on 295/55R20	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.3 mph	+0.3 mph
75 mph	75.0 mph	75.4 mph	+0.4 mph

Ride-height change: 295/55R20 raises the vehicle by 0.08 in (2.1 mm) at the axle (half the +4.3 mm diameter difference).

295/55R20 is 0.17 in taller than 265/70R18 and 30 mm wider, a 0.52% difference in overall diameter.

With the speedometer calibrated for 265/70R18, an indicated 60 mph is actually 60.3 mph on 295/55R20, and revolutions per mile change from 619 to 615.

295/55R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 265/70R18.

Size pages

Other comparisons with 265/70R18

Other comparisons with 295/55R20

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