TireSizesFinder

30x9.50R15 vs 215/85R16

215/85R16 is 0.39 in (9.9 mm) taller than 30x9.50R15, a +1.30% diameter difference. With the speedometer set for 30x9.50R15, an indicated 60 mph is 60.8 mph on 215/85R16.

Is this a safe swap?

Diameter difference +1.30%: within the ±3% guideline

By overall diameter alone, 215/85R16 falls inside the ±3% range commonly used as a guideline when replacing 30x9.50R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 30x9.50R15 (30.00 in) vs 215/85R16 (30.39 in)30x9.50R1530.00 in × 9.50 in215/85R1630.39 in × 8.46 in
Side profile and tread width, drawn to the same scale.
30x9.50R15 vs 215/85R16 differences
Measurement30x9.50R15215/85R16Difference% diff
Overall diameter30.00 in (762.0 mm)30.39 in (771.9 mm)+0.39 in (+9.9 mm)+1.30%
Sidewall height7.50 in (190.5 mm)7.19 in (182.8 mm)−0.31 in (−7.7 mm)−4.07%
Section width9.50 in (241.3 mm)8.46 in (215.0 mm)−1.04 in (−26.3 mm)−10.90%
Circumference94.25 in (2,393.9 mm)95.47 in (2,425.0 mm)+1.22 in (+31.1 mm)+1.30%
Revolutions per mile672664−9−1.28%
True speed with the speedometer calibrated for 30x9.50R15
IndicatedActual on 30x9.50R15Actual on 215/85R16Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.8 mph+0.8 mph
75 mph75.0 mph76.0 mph+1.0 mph

Ride-height change: 215/85R16 raises the vehicle by 0.19 in (4.9 mm) at the axle (half the +9.9 mm diameter difference).

215/85R16 is 0.39 in taller than 30x9.50R15 and 26 mm narrower, a 1.30% difference in overall diameter.

With the speedometer calibrated for 30x9.50R15, an indicated 60 mph is actually 60.8 mph on 215/85R16, and revolutions per mile change from 672 to 664.

215/85R16 mounts on a 16-inch wheel, a plus-1 fitment from the 15-inch wheel of 30x9.50R15.

Size pages

Other comparisons with 30x9.50R15

Other comparisons with 215/85R16

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