TireSizesFinder

31x10.50R15 vs 285/65R17

285/65R17 is 0.59 in (14.9 mm) taller than 31x10.50R15, a +1.89% diameter difference. With the speedometer set for 31x10.50R15, an indicated 60 mph is 61.1 mph on 285/65R17.

Is this a safe swap?

Diameter difference +1.89%: within the ±3% guideline

By overall diameter alone, 285/65R17 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 285/65R17 (31.59 in)31x10.50R1531.00 in × 10.50 in285/65R1731.59 in × 11.22 in
Side profile and tread width, drawn to the same scale.
31x10.50R15 vs 285/65R17 differences
Measurement31x10.50R15285/65R17Difference% diff
Overall diameter31.00 in (787.4 mm)31.59 in (802.3 mm)+0.59 in (+14.9 mm)+1.89%
Sidewall height8.00 in (203.2 mm)7.29 in (185.3 mm)−0.71 in (−17.9 mm)−8.83%
Section width10.50 in (266.7 mm)11.22 in (285.0 mm)+0.72 in (+18.3 mm)+6.86%
Circumference97.39 in (2,473.7 mm)99.23 in (2,520.5 mm)+1.84 in (+46.8 mm)+1.89%
Revolutions per mile651639−12−1.86%
True speed with the speedometer calibrated for 31x10.50R15
IndicatedActual on 31x10.50R15Actual on 285/65R17Difference
30 mph30.0 mph30.6 mph+0.6 mph
60 mph60.0 mph61.1 mph+1.1 mph
75 mph75.0 mph76.4 mph+1.4 mph

Ride-height change: 285/65R17 raises the vehicle by 0.29 in (7.4 mm) at the axle (half the +14.9 mm diameter difference).

285/65R17 is 0.59 in taller than 31x10.50R15 and 18 mm wider, a 1.89% difference in overall diameter.

With the speedometer calibrated for 31x10.50R15, an indicated 60 mph is actually 61.1 mph on 285/65R17, and revolutions per mile change from 651 to 639.

285/65R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 31x10.50R15.

Size pages

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