TireSizesFinder

35x12.50R17 vs 285/75R18

285/75R18 is 0.17 in (4.3 mm) shorter than 35x12.50R17, a −0.48% diameter difference. With the speedometer set for 35x12.50R17, an indicated 60 mph is 59.7 mph on 285/75R18.

Is this a safe swap?

Diameter difference −0.48%: under 1%

By overall diameter alone, 285/75R18 is a near match for 35x12.50R17; 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: 35x12.50R17 (35.00 in) vs 285/75R18 (34.83 in)35x12.50R1735.00 in × 12.50 in285/75R1834.83 in × 11.22 in
Side profile and tread width, drawn to the same scale.
35x12.50R17 vs 285/75R18 differences
Measurement35x12.50R17285/75R18Difference% diff
Overall diameter35.00 in (889.0 mm)34.83 in (884.7 mm)−0.17 in (−4.3 mm)−0.48%
Sidewall height9.00 in (228.6 mm)8.42 in (213.8 mm)−0.58 in (−14.8 mm)−6.50%
Section width12.50 in (317.5 mm)11.22 in (285.0 mm)−1.28 in (−32.5 mm)−10.24%
Circumference109.96 in (2,792.9 mm)109.42 in (2,779.4 mm)−0.53 in (−13.5 mm)−0.48%
Revolutions per mile576579+3+0.49%
True speed with the speedometer calibrated for 35x12.50R17
IndicatedActual on 35x12.50R17Actual on 285/75R18Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.7 mph−0.3 mph
75 mph75.0 mph74.6 mph−0.4 mph

Ride-height change: 285/75R18 lowers the vehicle by 0.08 in (2.1 mm) at the axle (half the −4.3 mm diameter difference).

285/75R18 is 0.17 in shorter than 35x12.50R17 and 33 mm narrower, a 0.48% difference in overall diameter.

With the speedometer calibrated for 35x12.50R17, an indicated 60 mph is actually 59.7 mph on 285/75R18, and revolutions per mile change from 576 to 579.

285/75R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 35x12.50R17.

Size pages

Other comparisons with 35x12.50R17

Other comparisons with 285/75R18

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