TireSizesFinder

255/70R15 vs 235/65R17

235/65R17 is 0.03 in (0.7 mm) shorter than 255/70R15, a −0.09% diameter difference. With the speedometer set for 255/70R15, an indicated 60 mph is 59.9 mph on 235/65R17.

Is this a safe swap?

Diameter difference −0.09%: under 1%

By overall diameter alone, 235/65R17 is a near match for 255/70R15; 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: 255/70R15 (29.06 in) vs 235/65R17 (29.03 in)255/70R1529.06 in × 10.04 in235/65R1729.03 in × 9.25 in
Side profile and tread width, drawn to the same scale.
255/70R15 vs 235/65R17 differences
Measurement255/70R15235/65R17Difference% diff
Overall diameter29.06 in (738.0 mm)29.03 in (737.3 mm)−0.03 in (−0.7 mm)−0.09%
Sidewall height7.03 in (178.5 mm)6.01 in (152.8 mm)−1.01 in (−25.7 mm)−14.43%
Section width10.04 in (255.0 mm)9.25 in (235.0 mm)−0.79 in (−20.0 mm)−7.84%
Circumference91.28 in (2,318.5 mm)91.19 in (2,316.3 mm)−0.09 in (−2.2 mm)−0.09%
Revolutions per mile694695+1+0.09%
True speed with the speedometer calibrated for 255/70R15
IndicatedActual on 255/70R15Actual on 235/65R17Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 235/65R17 lowers the vehicle by 0.01 in (0.4 mm) at the axle (half the −0.7 mm diameter difference).

235/65R17 is 0.03 in shorter than 255/70R15 and 20 mm narrower, a 0.09% difference in overall diameter.

With the speedometer calibrated for 255/70R15, an indicated 60 mph is actually 59.9 mph on 235/65R17, and revolutions per mile change from 694 to 695.

235/65R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 255/70R15.

Size pages

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