TireSizesFinder

33x12.50R17 vs 265/70R18

265/70R18 is 0.39 in (10.0 mm) shorter than 33x12.50R17, a −1.19% diameter difference. With the speedometer set for 33x12.50R17, an indicated 60 mph is 59.3 mph on 265/70R18.

Is this a safe swap?

Diameter difference −1.19%: within the ±3% guideline

By overall diameter alone, 265/70R18 falls inside the ±3% range commonly used as a guideline when replacing 33x12.50R17. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 33x12.50R17 (33.00 in) vs 265/70R18 (32.61 in)33x12.50R1733.00 in × 12.50 in265/70R1832.61 in × 10.43 in
Side profile and tread width, drawn to the same scale.
33x12.50R17 vs 265/70R18 differences
Measurement33x12.50R17265/70R18Difference% diff
Overall diameter33.00 in (838.2 mm)32.61 in (828.2 mm)−0.39 in (−10.0 mm)−1.19%
Sidewall height8.00 in (203.2 mm)7.30 in (185.5 mm)−0.70 in (−17.7 mm)−8.71%
Section width12.50 in (317.5 mm)10.43 in (265.0 mm)−2.07 in (−52.5 mm)−16.54%
Circumference103.67 in (2,633.3 mm)102.44 in (2,601.9 mm)−1.24 in (−31.4 mm)−1.19%
Revolutions per mile611619+7+1.21%
True speed with the speedometer calibrated for 33x12.50R17
IndicatedActual on 33x12.50R17Actual on 265/70R18Difference
30 mph30.0 mph29.6 mph−0.4 mph
60 mph60.0 mph59.3 mph−0.7 mph
75 mph75.0 mph74.1 mph−0.9 mph

Ride-height change: 265/70R18 lowers the vehicle by 0.20 in (5.0 mm) at the axle (half the −10.0 mm diameter difference).

265/70R18 is 0.39 in shorter than 33x12.50R17 and 53 mm narrower, a 1.19% difference in overall diameter.

With the speedometer calibrated for 33x12.50R17, an indicated 60 mph is actually 59.3 mph on 265/70R18, and revolutions per mile change from 611 to 619.

265/70R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 33x12.50R17.

Size pages

Other comparisons with 33x12.50R17

Other comparisons with 265/70R18

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