TireSizesFinder

225/65R15 vs 255/45R17

255/45R17 is 0.48 in (12.2 mm) shorter than 225/65R15, a −1.81% diameter difference. With the speedometer set for 225/65R15, an indicated 60 mph is 58.9 mph on 255/45R17.

Is this a safe swap?

Diameter difference −1.81%: within the ±3% guideline

By overall diameter alone, 255/45R17 falls inside the ±3% range commonly used as a guideline when replacing 225/65R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 225/65R15 (26.52 in) vs 255/45R17 (26.04 in)225/65R1526.52 in × 8.86 in255/45R1726.04 in × 10.04 in
Side profile and tread width, drawn to the same scale.
225/65R15 vs 255/45R17 differences
Measurement225/65R15255/45R17Difference% diff
Overall diameter26.52 in (673.5 mm)26.04 in (661.3 mm)−0.48 in (−12.2 mm)−1.81%
Sidewall height5.76 in (146.3 mm)4.52 in (114.8 mm)−1.24 in (−31.5 mm)−21.54%
Section width8.86 in (225.0 mm)10.04 in (255.0 mm)+1.18 in (+30.0 mm)+13.33%
Circumference83.30 in (2,115.9 mm)81.79 in (2,077.5 mm)−1.51 in (−38.3 mm)−1.81%
Revolutions per mile761775+14+1.84%
True speed with the speedometer calibrated for 225/65R15
IndicatedActual on 225/65R15Actual on 255/45R17Difference
30 mph30.0 mph29.5 mph−0.5 mph
60 mph60.0 mph58.9 mph−1.1 mph
75 mph75.0 mph73.6 mph−1.4 mph

Ride-height change: 255/45R17 lowers the vehicle by 0.24 in (6.1 mm) at the axle (half the −12.2 mm diameter difference).

255/45R17 is 0.48 in shorter than 225/65R15 and 30 mm wider, a 1.81% difference in overall diameter.

With the speedometer calibrated for 225/65R15, an indicated 60 mph is actually 58.9 mph on 255/45R17, and revolutions per mile change from 761 to 775.

255/45R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 225/65R15.

Size pages

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