TireSizesFinder

235/60R15 vs 255/45R17

255/45R17 is 0.07 in (1.7 mm) shorter than 235/60R15, a −0.26% diameter difference. With the speedometer set for 235/60R15, an indicated 60 mph is 59.8 mph on 255/45R17.

Is this a safe swap?

Diameter difference −0.26%: under 1%

By overall diameter alone, 255/45R17 is a near match for 235/60R15; 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: 235/60R15 (26.10 in) vs 255/45R17 (26.04 in)235/60R1526.10 in × 9.25 in255/45R1726.04 in × 10.04 in
Side profile and tread width, drawn to the same scale.
235/60R15 vs 255/45R17 differences
Measurement235/60R15255/45R17Difference% diff
Overall diameter26.10 in (663.0 mm)26.04 in (661.3 mm)−0.07 in (−1.7 mm)−0.26%
Sidewall height5.55 in (141.0 mm)4.52 in (114.8 mm)−1.03 in (−26.2 mm)−18.62%
Section width9.25 in (235.0 mm)10.04 in (255.0 mm)+0.79 in (+20.0 mm)+8.51%
Circumference82.00 in (2,082.9 mm)81.79 in (2,077.5 mm)−0.21 in (−5.3 mm)−0.26%
Revolutions per mile773775+2+0.26%
True speed with the speedometer calibrated for 235/60R15
IndicatedActual on 235/60R15Actual on 255/45R17Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.8 mph−0.2 mph

Ride-height change: 255/45R17 lowers the vehicle by 0.03 in (0.9 mm) at the axle (half the −1.7 mm diameter difference).

255/45R17 is 0.07 in shorter than 235/60R15 and 20 mm wider, a 0.26% difference in overall diameter.

With the speedometer calibrated for 235/60R15, an indicated 60 mph is actually 59.8 mph on 255/45R17, and revolutions per mile change from 773 to 775.

255/45R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 235/60R15.

Size pages

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