TireSizesFinder

31x10.50R16 vs 235/85R16

235/85R16 is 0.73 in (18.5 mm) taller than 31x10.50R16, a +2.35% diameter difference. With the speedometer set for 31x10.50R16, an indicated 60 mph is 61.4 mph on 235/85R16.

Is this a safe swap?

Diameter difference +2.35%: within the ±3% guideline

By overall diameter alone, 235/85R16 falls inside the ±3% range commonly used as a guideline when replacing 31x10.50R16. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 31x10.50R16 (31.00 in) vs 235/85R16 (31.73 in)31x10.50R1631.00 in × 10.50 in235/85R1631.73 in × 9.25 in
Side profile and tread width, drawn to the same scale.
31x10.50R16 vs 235/85R16 differences
Measurement31x10.50R16235/85R16Difference% diff
Overall diameter31.00 in (787.4 mm)31.73 in (805.9 mm)+0.73 in (+18.5 mm)+2.35%
Sidewall height7.50 in (190.5 mm)7.86 in (199.8 mm)+0.36 in (+9.3 mm)+4.86%
Section width10.50 in (266.7 mm)9.25 in (235.0 mm)−1.25 in (−31.7 mm)−11.89%
Circumference97.39 in (2,473.7 mm)99.68 in (2,531.8 mm)+2.29 in (+58.1 mm)+2.35%
Revolutions per mile651636−15−2.30%
True speed with the speedometer calibrated for 31x10.50R16
IndicatedActual on 31x10.50R16Actual on 235/85R16Difference
30 mph30.0 mph30.7 mph+0.7 mph
60 mph60.0 mph61.4 mph+1.4 mph
75 mph75.0 mph76.8 mph+1.8 mph

Ride-height change: 235/85R16 raises the vehicle by 0.36 in (9.3 mm) at the axle (half the +18.5 mm diameter difference).

235/85R16 is 0.73 in taller than 31x10.50R16 and 32 mm narrower, a 2.35% difference in overall diameter.

With the speedometer calibrated for 31x10.50R16, an indicated 60 mph is actually 61.4 mph on 235/85R16, and revolutions per mile change from 651 to 636.

Both sizes mount on 16-inch wheels.

Size pages

Other comparisons with 31x10.50R16

Other comparisons with 235/85R16

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