295/70R17 vs 33x12.50R18

33x12.50R18 is 0.26 in (6.6 mm) shorter than 295/70R17, a −0.78% diameter difference. With the speedometer set for 295/70R17, an indicated 60 mph is 59.5 mph on 33x12.50R18.

Is this a safe swap?

Diameter difference −0.78%: under 1%

By overall diameter alone, 33x12.50R18 is a near match for 295/70R17; 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: 295/70R17 (33.26 in) vs 33x12.50R18 (33.00 in)295/70R1733.26 in × 11.61 in33x12.50R1833.00 in × 12.50 in
Side profile and tread width, drawn to the same scale.
295/70R17 vs 33x12.50R18 differences
Measurement295/70R1733x12.50R18Difference% diff
Overall diameter33.26 in (844.8 mm)33.00 in (838.2 mm)−0.26 in (−6.6 mm)−0.78%
Sidewall height8.13 in (206.5 mm)7.50 in (190.5 mm)−0.63 in (−16.0 mm)−7.75%
Section width11.61 in (295.0 mm)12.50 in (317.5 mm)+0.89 in (+22.5 mm)+7.63%
Circumference104.49 in (2,654.0 mm)103.67 in (2,633.3 mm)−0.82 in (−20.7 mm)−0.78%
Revolutions per mile606611+5+0.79%
True speed with the speedometer calibrated for 295/70R17
IndicatedActual on 295/70R17Actual on 33x12.50R18Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.5 mph−0.5 mph
75 mph75.0 mph74.4 mph−0.6 mph

Ride-height change: 33x12.50R18 lowers the vehicle by 0.13 in (3.3 mm) at the axle (half the −6.6 mm diameter difference).

33x12.50R18 is 0.26 in shorter than 295/70R17 and 23 mm wider, a 0.78% difference in overall diameter.

With the speedometer calibrated for 295/70R17, an indicated 60 mph is actually 59.5 mph on 33x12.50R18, and revolutions per mile change from 606 to 611.

33x12.50R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 295/70R17.

Size pages

Other comparisons with 295/70R17

Other comparisons with 33x12.50R18

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