TireSizesFinder

31x10.50R15 vs 215/85R16

215/85R16 is 0.61 in (15.5 mm) shorter than 31x10.50R15, a −1.97% diameter difference. With the speedometer set for 31x10.50R15, an indicated 60 mph is 58.8 mph on 215/85R16.

Is this a safe swap?

Diameter difference −1.97%: within the ±3% guideline

By overall diameter alone, 215/85R16 falls inside the ±3% range commonly used as a guideline when replacing 31x10.50R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 31x10.50R15 (31.00 in) vs 215/85R16 (30.39 in)31x10.50R1531.00 in × 10.50 in215/85R1630.39 in × 8.46 in
Side profile and tread width, drawn to the same scale.
31x10.50R15 vs 215/85R16 differences
Measurement31x10.50R15215/85R16Difference% diff
Overall diameter31.00 in (787.4 mm)30.39 in (771.9 mm)−0.61 in (−15.5 mm)−1.97%
Sidewall height8.00 in (203.2 mm)7.19 in (182.8 mm)−0.81 in (−20.4 mm)−10.06%
Section width10.50 in (266.7 mm)8.46 in (215.0 mm)−2.04 in (−51.7 mm)−19.39%
Circumference97.39 in (2,473.7 mm)95.47 in (2,425.0 mm)−1.92 in (−48.7 mm)−1.97%
Revolutions per mile651664+13+2.01%
True speed with the speedometer calibrated for 31x10.50R15
IndicatedActual on 31x10.50R15Actual on 215/85R16Difference
30 mph30.0 mph29.4 mph−0.6 mph
60 mph60.0 mph58.8 mph−1.2 mph
75 mph75.0 mph73.5 mph−1.5 mph

Ride-height change: 215/85R16 lowers the vehicle by 0.31 in (7.8 mm) at the axle (half the −15.5 mm diameter difference).

215/85R16 is 0.61 in shorter than 31x10.50R15 and 52 mm narrower, a 1.97% difference in overall diameter.

With the speedometer calibrated for 31x10.50R15, an indicated 60 mph is actually 58.8 mph on 215/85R16, and revolutions per mile change from 651 to 664.

215/85R16 mounts on a 16-inch wheel, a plus-1 fitment from the 15-inch wheel of 31x10.50R15.

Size pages

Other comparisons with 31x10.50R15

Other comparisons with 215/85R16

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