295/55R20 vs 33x12.50R20

33x12.50R20 is 0.22 in (5.7 mm) taller than 295/55R20, a +0.68% diameter difference. With the speedometer set for 295/55R20, an indicated 60 mph is 60.4 mph on 33x12.50R20.

Is this a safe swap?

Diameter difference +0.68%: under 1%

By overall diameter alone, 33x12.50R20 is a near match for 295/55R20; 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.

295/55R20 vs 33x12.50R20 differences
Measurement	295/55R20	33x12.50R20	Difference	% diff
Overall diameter	32.78 in (832.5 mm)	33.00 in (838.2 mm)	+0.22 in (+5.7 mm)	+0.68%
Sidewall height	6.39 in (162.3 mm)	6.50 in (165.1 mm)	+0.11 in (+2.8 mm)	+1.76%
Section width	11.61 in (295.0 mm)	12.50 in (317.5 mm)	+0.89 in (+22.5 mm)	+7.63%
Circumference	102.97 in (2,615.4 mm)	103.67 in (2,633.3 mm)	+0.71 in (+17.9 mm)	+0.68%
Revolutions per mile	615	611	−4	−0.68%

True speed with the speedometer calibrated for 295/55R20
Indicated	Actual on 295/55R20	Actual on 33x12.50R20	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.4 mph	+0.4 mph
75 mph	75.0 mph	75.5 mph	+0.5 mph

Ride-height change: 33x12.50R20 raises the vehicle by 0.11 in (2.9 mm) at the axle (half the +5.7 mm diameter difference).

33x12.50R20 is 0.22 in taller than 295/55R20 and 23 mm wider, a 0.68% difference in overall diameter.

With the speedometer calibrated for 295/55R20, an indicated 60 mph is actually 60.4 mph on 33x12.50R20, and revolutions per mile change from 615 to 611.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 295/55R20

Other comparisons with 33x12.50R20

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