265/75R15 vs 245/70R17

245/70R17 is 0.15 in (3.7 mm) shorter than 265/75R15, a −0.48% diameter difference. With the speedometer set for 265/75R15, an indicated 60 mph is 59.7 mph on 245/70R17.

Is this a safe swap?

Diameter difference −0.48%: under 1%

By overall diameter alone, 245/70R17 is a near match for 265/75R15; the speedometer changes by less than 1%. 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.

265/75R15 vs 245/70R17 differences
Measurement	265/75R15	245/70R17	Difference	% diff
Overall diameter	30.65 in (778.5 mm)	30.50 in (774.8 mm)	−0.15 in (−3.7 mm)	−0.48%
Sidewall height	7.82 in (198.8 mm)	6.75 in (171.5 mm)	−1.07 in (−27.2 mm)	−13.71%
Section width	10.43 in (265.0 mm)	9.65 in (245.0 mm)	−0.79 in (−20.0 mm)	−7.55%
Circumference	96.29 in (2,445.7 mm)	95.83 in (2,434.1 mm)	−0.46 in (−11.6 mm)	−0.48%
Revolutions per mile	658	661	+3	+0.48%

True speed with the speedometer calibrated for 265/75R15
Indicated	Actual on 265/75R15	Actual on 245/70R17	Difference
30 mph	30.0 mph	29.9 mph	−0.1 mph
60 mph	60.0 mph	59.7 mph	−0.3 mph
75 mph	75.0 mph	74.6 mph	−0.4 mph

Ride-height change: 245/70R17 lowers the vehicle by 0.07 in (1.9 mm) at the axle (half the −3.7 mm diameter difference).

245/70R17 is 0.15 in shorter than 265/75R15 and 20 mm narrower, a 0.48% difference in overall diameter.

With the speedometer calibrated for 265/75R15, an indicated 60 mph is actually 59.7 mph on 245/70R17, and revolutions per mile change from 658 to 661.

245/70R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 265/75R15.

Size pages

Other comparisons with 265/75R15

Other comparisons with 245/70R17

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