275/60R20 vs 33x12.50R20

33x12.50R20 is 0.01 in (0.2 mm) taller than 275/60R20, a +0.02% diameter difference. With the speedometer set for 275/60R20, an indicated 60 mph is 60.0 mph on 33x12.50R20.

Is this a safe swap?

Diameter difference +0.02%: under 1%

By overall diameter alone, 33x12.50R20 is a near match for 275/60R20; 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.

275/60R20 vs 33x12.50R20 differences
Measurement	275/60R20	33x12.50R20	Difference	% diff
Overall diameter	32.99 in (838.0 mm)	33.00 in (838.2 mm)	+0.01 in (+0.2 mm)	+0.02%
Sidewall height	6.50 in (165.0 mm)	6.50 in (165.1 mm)	0.00 in (+0.1 mm)	+0.06%
Section width	10.83 in (275.0 mm)	12.50 in (317.5 mm)	+1.67 in (+42.5 mm)	+15.45%
Circumference	103.65 in (2,632.7 mm)	103.67 in (2,633.3 mm)	+0.02 in (+0.6 mm)	+0.02%
Revolutions per mile	611	611	0	−0.02%

True speed with the speedometer calibrated for 275/60R20
Indicated	Actual on 275/60R20	Actual on 33x12.50R20
30 mph	30.0 mph	30.0 mph
60 mph	60.0 mph	60.0 mph
75 mph	75.0 mph	75.0 mph

Ride-height change: 33x12.50R20 raises the vehicle by 0.00 in (0.1 mm) at the axle (half the +0.2 mm diameter difference).

33x12.50R20 is 0.01 in taller than 275/60R20 and 43 mm wider, a 0.02% difference in overall diameter.

With the speedometer calibrated for 275/60R20, an indicated 60 mph is actually 60.0 mph on 33x12.50R20, and revolutions per mile change from 611 to 611.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 275/60R20

Other comparisons with 33x12.50R20

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