TireSizesFinder

35x12.50R18 vs 35x12.50R20

35x12.50R20 is 0.00 in (0.0 mm) taller than 35x12.50R18, a 0.00% diameter difference. With the speedometer set for 35x12.50R18, an indicated 60 mph is 60.0 mph on 35x12.50R20.

Is this a safe swap?

Diameter difference 0.00%: under 1%

By overall diameter alone, 35x12.50R20 is a near match for 35x12.50R18; 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: 35x12.50R18 (35.00 in) vs 35x12.50R20 (35.00 in)35x12.50R1835.00 in × 12.50 in35x12.50R2035.00 in × 12.50 in
Side profile and tread width, drawn to the same scale.
35x12.50R18 vs 35x12.50R20 differences
Measurement35x12.50R1835x12.50R20Difference% diff
Overall diameter35.00 in (889.0 mm)35.00 in (889.0 mm)0.00 in (0.0 mm)0.00%
Sidewall height8.50 in (215.9 mm)7.50 in (190.5 mm)−1.00 in (−25.4 mm)−11.76%
Section width12.50 in (317.5 mm)12.50 in (317.5 mm)0.00 in (0.0 mm)0.00%
Circumference109.96 in (2,792.9 mm)109.96 in (2,792.9 mm)0.00 in (0.0 mm)0.00%
Revolutions per mile57657600.00%
True speed with the speedometer calibrated for 35x12.50R18
IndicatedActual on 35x12.50R18Actual on 35x12.50R20Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.0 mph0.0 mph

Ride-height change: 35x12.50R20 does not change the vehicle at the axle (half the 0.0 mm diameter difference).

35x12.50R20 is the same height as 35x12.50R18 and the same width, a 0.00% difference in overall diameter.

With the speedometer calibrated for 35x12.50R18, an indicated 60 mph is actually 60.0 mph on 35x12.50R20, and revolutions per mile change from 576 to 576.

35x12.50R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 35x12.50R18.

Size pages

Other comparisons with 35x12.50R18

Other comparisons with 35x12.50R20

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