295/35R19 vs 255/35R20

255/35R20 is 0.10 in (2.6 mm) shorter than 295/35R19, a −0.38% diameter difference. With the speedometer set for 295/35R19, an indicated 60 mph is 59.8 mph on 255/35R20.

Is this a safe swap?

Diameter difference −0.38%: under 1%

By overall diameter alone, 255/35R20 is a near match for 295/35R19; 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.

295/35R19 vs 255/35R20 differences
Measurement	295/35R19	255/35R20	Difference	% diff
Overall diameter	27.13 in (689.1 mm)	27.03 in (686.5 mm)	−0.10 in (−2.6 mm)	−0.38%
Sidewall height	4.06 in (103.3 mm)	3.51 in (89.3 mm)	−0.55 in (−14.0 mm)	−13.56%
Section width	11.61 in (295.0 mm)	10.04 in (255.0 mm)	−1.57 in (−40.0 mm)	−13.56%
Circumference	85.23 in (2,164.9 mm)	84.91 in (2,156.7 mm)	−0.32 in (−8.2 mm)	−0.38%
Revolutions per mile	743	746	+3	+0.38%

True speed with the speedometer calibrated for 295/35R19
Indicated	Actual on 295/35R19	Actual on 255/35R20	Difference
30 mph	30.0 mph	29.9 mph	−0.1 mph
60 mph	60.0 mph	59.8 mph	−0.2 mph
75 mph	75.0 mph	74.7 mph	−0.3 mph

Ride-height change: 255/35R20 lowers the vehicle by 0.05 in (1.3 mm) at the axle (half the −2.6 mm diameter difference).

255/35R20 is 0.10 in shorter than 295/35R19 and 40 mm narrower, a 0.38% difference in overall diameter.

With the speedometer calibrated for 295/35R19, an indicated 60 mph is actually 59.8 mph on 255/35R20, and revolutions per mile change from 743 to 746.

255/35R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 295/35R19.

Size pages

Other comparisons with 295/35R19

Other comparisons with 255/35R20

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