245/75R15 vs 235/65R17

235/65R17 is 0.44 in (11.2 mm) shorter than 245/75R15, a −1.50% diameter difference. With the speedometer set for 245/75R15, an indicated 60 mph is 59.1 mph on 235/65R17.

Is this a safe swap?

Diameter difference −1.50%: within the ±3% guideline

By overall diameter alone, 235/65R17 falls inside the ±3% range commonly used as a guideline when replacing 245/75R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

245/75R15 vs 235/65R17 differences
Measurement	245/75R15	235/65R17	Difference	% diff
Overall diameter	29.47 in (748.5 mm)	29.03 in (737.3 mm)	−0.44 in (−11.2 mm)	−1.50%
Sidewall height	7.23 in (183.8 mm)	6.01 in (152.8 mm)	−1.22 in (−31.0 mm)	−16.87%
Section width	9.65 in (245.0 mm)	9.25 in (235.0 mm)	−0.39 in (−10.0 mm)	−4.08%
Circumference	92.58 in (2,351.5 mm)	91.19 in (2,316.3 mm)	−1.39 in (−35.2 mm)	−1.50%
Revolutions per mile	684	695	+10	+1.52%

True speed with the speedometer calibrated for 245/75R15
Indicated	Actual on 245/75R15	Actual on 235/65R17	Difference
30 mph	30.0 mph	29.6 mph	−0.4 mph
60 mph	60.0 mph	59.1 mph	−0.9 mph
75 mph	75.0 mph	73.9 mph	−1.1 mph

Ride-height change: 235/65R17 lowers the vehicle by 0.22 in (5.6 mm) at the axle (half the −11.2 mm diameter difference).

235/65R17 is 0.44 in shorter than 245/75R15 and 10 mm narrower, a 1.50% difference in overall diameter.

With the speedometer calibrated for 245/75R15, an indicated 60 mph is actually 59.1 mph on 235/65R17, and revolutions per mile change from 684 to 695.

235/65R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 245/75R15.

Size pages

Other comparisons with 245/75R15

Other comparisons with 235/65R17

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.