235/55R19 vs 295/40R20

295/40R20 is 0.11 in (2.9 mm) taller than 235/55R19, a +0.39% diameter difference. With the speedometer set for 235/55R19, an indicated 60 mph is 60.2 mph on 295/40R20.

Is this a safe swap?

Diameter difference +0.39%: under 1%

By overall diameter alone, 295/40R20 is a near match for 235/55R19; 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.

235/55R19 vs 295/40R20 differences
Measurement	235/55R19	295/40R20	Difference	% diff
Overall diameter	29.18 in (741.1 mm)	29.29 in (744.0 mm)	+0.11 in (+2.9 mm)	+0.39%
Sidewall height	5.09 in (129.3 mm)	4.65 in (118.0 mm)	−0.44 in (−11.2 mm)	−8.70%
Section width	9.25 in (235.0 mm)	11.61 in (295.0 mm)	+2.36 in (+60.0 mm)	+25.53%
Circumference	91.66 in (2,328.2 mm)	92.02 in (2,337.3 mm)	+0.36 in (+9.1 mm)	+0.39%
Revolutions per mile	691	689	−3	−0.39%

True speed with the speedometer calibrated for 235/55R19
Indicated	Actual on 235/55R19	Actual on 295/40R20	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.2 mph	+0.2 mph
75 mph	75.0 mph	75.3 mph	+0.3 mph

Ride-height change: 295/40R20 raises the vehicle by 0.06 in (1.5 mm) at the axle (half the +2.9 mm diameter difference).

295/40R20 is 0.11 in taller than 235/55R19 and 60 mm wider, a 0.39% difference in overall diameter.

With the speedometer calibrated for 235/55R19, an indicated 60 mph is actually 60.2 mph on 295/40R20, and revolutions per mile change from 691 to 689.

295/40R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 235/55R19.

Size pages

Other comparisons with 235/55R19

Other comparisons with 295/40R20

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