TireSizesFinder

30x9.50R15 vs 225/75R17

225/75R17 is 0.29 in (7.3 mm) taller than 30x9.50R15, a +0.96% diameter difference. With the speedometer set for 30x9.50R15, an indicated 60 mph is 60.6 mph on 225/75R17.

Is this a safe swap?

Diameter difference +0.96%: under 1%

By overall diameter alone, 225/75R17 is a near match for 30x9.50R15; 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: 30x9.50R15 (30.00 in) vs 225/75R17 (30.29 in)30x9.50R1530.00 in × 9.50 in225/75R1730.29 in × 8.86 in
Side profile and tread width, drawn to the same scale.
30x9.50R15 vs 225/75R17 differences
Measurement30x9.50R15225/75R17Difference% diff
Overall diameter30.00 in (762.0 mm)30.29 in (769.3 mm)+0.29 in (+7.3 mm)+0.96%
Sidewall height7.50 in (190.5 mm)6.64 in (168.8 mm)−0.86 in (−21.7 mm)−11.42%
Section width9.50 in (241.3 mm)8.86 in (225.0 mm)−0.64 in (−16.3 mm)−6.76%
Circumference94.25 in (2,393.9 mm)95.15 in (2,416.8 mm)+0.90 in (+22.9 mm)+0.96%
Revolutions per mile672666−6−0.95%
True speed with the speedometer calibrated for 30x9.50R15
IndicatedActual on 30x9.50R15Actual on 225/75R17Difference
30 mph30.0 mph30.3 mph+0.3 mph
60 mph60.0 mph60.6 mph+0.6 mph
75 mph75.0 mph75.7 mph+0.7 mph

Ride-height change: 225/75R17 raises the vehicle by 0.14 in (3.6 mm) at the axle (half the +7.3 mm diameter difference).

225/75R17 is 0.29 in taller than 30x9.50R15 and 16 mm narrower, a 0.96% difference in overall diameter.

With the speedometer calibrated for 30x9.50R15, an indicated 60 mph is actually 60.6 mph on 225/75R17, and revolutions per mile change from 672 to 666.

225/75R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 30x9.50R15.

Size pages

Other comparisons with 30x9.50R15

Other comparisons with 225/75R17

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