TireSizesFinder

33x12.50R18 vs 295/55R20

295/55R20 is 0.22 in (5.7 mm) shorter than 33x12.50R18, a −0.68% diameter difference. With the speedometer set for 33x12.50R18, an indicated 60 mph is 59.6 mph on 295/55R20.

Is this a safe swap?

Diameter difference −0.68%: under 1%

By overall diameter alone, 295/55R20 is a near match for 33x12.50R18; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 33x12.50R18 (33.00 in) vs 295/55R20 (32.78 in)33x12.50R1833.00 in × 12.50 in295/55R2032.78 in × 11.61 in
Side profile and tread width, drawn to the same scale.
33x12.50R18 vs 295/55R20 differences
Measurement33x12.50R18295/55R20Difference% diff
Overall diameter33.00 in (838.2 mm)32.78 in (832.5 mm)−0.22 in (−5.7 mm)−0.68%
Sidewall height7.50 in (190.5 mm)6.39 in (162.3 mm)−1.11 in (−28.2 mm)−14.83%
Section width12.50 in (317.5 mm)11.61 in (295.0 mm)−0.89 in (−22.5 mm)−7.09%
Circumference103.67 in (2,633.3 mm)102.97 in (2,615.4 mm)−0.71 in (−17.9 mm)−0.68%
Revolutions per mile611615+4+0.68%
True speed with the speedometer calibrated for 33x12.50R18
IndicatedActual on 33x12.50R18Actual on 295/55R20Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.5 mph−0.5 mph

Ride-height change: 295/55R20 lowers the vehicle by 0.11 in (2.9 mm) at the axle (half the −5.7 mm diameter difference).

295/55R20 is 0.22 in shorter than 33x12.50R18 and 23 mm narrower, a 0.68% difference in overall diameter.

With the speedometer calibrated for 33x12.50R18, an indicated 60 mph is actually 59.6 mph on 295/55R20, and revolutions per mile change from 611 to 615.

295/55R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 33x12.50R18.

Size pages

Other comparisons with 33x12.50R18

Other comparisons with 295/55R20

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.