TireSizesFinder

255/70R16 vs 235/70R17

235/70R17 is 0.10 in (2.6 mm) shorter than 255/70R16, a −0.34% diameter difference. With the speedometer set for 255/70R16, an indicated 60 mph is 59.8 mph on 235/70R17.

Is this a safe swap?

Diameter difference −0.34%: under 1%

By overall diameter alone, 235/70R17 is a near match for 255/70R16; 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: 255/70R16 (30.06 in) vs 235/70R17 (29.95 in)255/70R1630.06 in × 10.04 in235/70R1729.95 in × 9.25 in
Side profile and tread width, drawn to the same scale.
255/70R16 vs 235/70R17 differences
Measurement255/70R16235/70R17Difference% diff
Overall diameter30.06 in (763.4 mm)29.95 in (760.8 mm)−0.10 in (−2.6 mm)−0.34%
Sidewall height7.03 in (178.5 mm)6.48 in (164.5 mm)−0.55 in (−14.0 mm)−7.84%
Section width10.04 in (255.0 mm)9.25 in (235.0 mm)−0.79 in (−20.0 mm)−7.84%
Circumference94.42 in (2,398.3 mm)94.10 in (2,390.1 mm)−0.32 in (−8.2 mm)−0.34%
Revolutions per mile671673+2+0.34%
True speed with the speedometer calibrated for 255/70R16
IndicatedActual on 255/70R16Actual on 235/70R17Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 235/70R17 lowers the vehicle by 0.05 in (1.3 mm) at the axle (half the −2.6 mm diameter difference).

235/70R17 is 0.10 in shorter than 255/70R16 and 20 mm narrower, a 0.34% difference in overall diameter.

With the speedometer calibrated for 255/70R16, an indicated 60 mph is actually 59.8 mph on 235/70R17, and revolutions per mile change from 671 to 673.

235/70R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 255/70R16.

Size pages

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