TireSizesFinder

255/70R16 vs 245/70R17

245/70R17 is 0.45 in (11.4 mm) taller than 255/70R16, a +1.49% diameter difference. With the speedometer set for 255/70R16, an indicated 60 mph is 60.9 mph on 245/70R17.

Is this a safe swap?

Diameter difference +1.49%: within the ±3% guideline

By overall diameter alone, 245/70R17 falls inside the ±3% range commonly used as a guideline when replacing 255/70R16. 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 245/70R17 (30.50 in)255/70R1630.06 in × 10.04 in245/70R1730.50 in × 9.65 in
Side profile and tread width, drawn to the same scale.
255/70R16 vs 245/70R17 differences
Measurement255/70R16245/70R17Difference% diff
Overall diameter30.06 in (763.4 mm)30.50 in (774.8 mm)+0.45 in (+11.4 mm)+1.49%
Sidewall height7.03 in (178.5 mm)6.75 in (171.5 mm)−0.28 in (−7.0 mm)−3.92%
Section width10.04 in (255.0 mm)9.65 in (245.0 mm)−0.39 in (−10.0 mm)−3.92%
Circumference94.42 in (2,398.3 mm)95.83 in (2,434.1 mm)+1.41 in (+35.8 mm)+1.49%
Revolutions per mile671661−10−1.47%
True speed with the speedometer calibrated for 255/70R16
IndicatedActual on 255/70R16Actual on 245/70R17Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.9 mph+0.9 mph
75 mph75.0 mph76.1 mph+1.1 mph

Ride-height change: 245/70R17 raises the vehicle by 0.22 in (5.7 mm) at the axle (half the +11.4 mm diameter difference).

245/70R17 is 0.45 in taller than 255/70R16 and 10 mm narrower, a 1.49% difference in overall diameter.

With the speedometer calibrated for 255/70R16, an indicated 60 mph is actually 60.9 mph on 245/70R17, and revolutions per mile change from 671 to 661.

245/70R17 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.