255/70R15 vs 225/65R17

225/65R17 is 0.54 in (13.7 mm) shorter than 255/70R15, a −1.86% diameter difference. With the speedometer set for 255/70R15, an indicated 60 mph is 58.9 mph on 225/65R17.

Is this a safe swap?

Diameter difference −1.86%: within the ±3% guideline

By overall diameter alone, 225/65R17 falls inside the ±3% range commonly used as a guideline when replacing 255/70R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

255/70R15 vs 225/65R17 differences
Measurement	255/70R15	225/65R17	Difference	% diff
Overall diameter	29.06 in (738.0 mm)	28.52 in (724.3 mm)	−0.54 in (−13.7 mm)	−1.86%
Sidewall height	7.03 in (178.5 mm)	5.76 in (146.3 mm)	−1.27 in (−32.2 mm)	−18.07%
Section width	10.04 in (255.0 mm)	8.86 in (225.0 mm)	−1.18 in (−30.0 mm)	−11.76%
Circumference	91.28 in (2,318.5 mm)	89.58 in (2,275.5 mm)	−1.69 in (−43.0 mm)	−1.86%
Revolutions per mile	694	707	+13	+1.89%

True speed with the speedometer calibrated for 255/70R15
Indicated	Actual on 255/70R15	Actual on 225/65R17	Difference
30 mph	30.0 mph	29.4 mph	−0.6 mph
60 mph	60.0 mph	58.9 mph	−1.1 mph
75 mph	75.0 mph	73.6 mph	−1.4 mph

Ride-height change: 225/65R17 lowers the vehicle by 0.27 in (6.9 mm) at the axle (half the −13.7 mm diameter difference).

225/65R17 is 0.54 in shorter than 255/70R15 and 30 mm narrower, a 1.86% difference in overall diameter.

With the speedometer calibrated for 255/70R15, an indicated 60 mph is actually 58.9 mph on 225/65R17, and revolutions per mile change from 694 to 707.

225/65R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 255/70R15.

Size pages

Other comparisons with 255/70R15

Other comparisons with 225/65R17

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.