275/65R17 vs 245/75R17

245/75R17 is 0.39 in (10.0 mm) taller than 275/65R17, a +1.27% diameter difference. With the speedometer set for 275/65R17, an indicated 60 mph is 60.8 mph on 245/75R17.

Is this a safe swap?

Diameter difference +1.27%: within the ±3% guideline

By overall diameter alone, 245/75R17 falls inside the ±3% range commonly used as a guideline when replacing 275/65R17. 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.

275/65R17 vs 245/75R17 differences
Measurement	275/65R17	245/75R17	Difference	% diff
Overall diameter	31.07 in (789.3 mm)	31.47 in (799.3 mm)	+0.39 in (+10.0 mm)	+1.27%
Sidewall height	7.04 in (178.8 mm)	7.23 in (183.8 mm)	+0.20 in (+5.0 mm)	+2.80%
Section width	10.83 in (275.0 mm)	9.65 in (245.0 mm)	−1.18 in (−30.0 mm)	−10.91%
Circumference	97.62 in (2,479.7 mm)	98.86 in (2,511.1 mm)	+1.24 in (+31.4 mm)	+1.27%
Revolutions per mile	649	641	−8	−1.25%

True speed with the speedometer calibrated for 275/65R17
Indicated	Actual on 275/65R17	Actual on 245/75R17	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.8 mph	+0.8 mph
75 mph	75.0 mph	76.0 mph	+1.0 mph

Ride-height change: 245/75R17 raises the vehicle by 0.20 in (5.0 mm) at the axle (half the +10.0 mm diameter difference).

245/75R17 is 0.39 in taller than 275/65R17 and 30 mm narrower, a 1.27% difference in overall diameter.

With the speedometer calibrated for 275/65R17, an indicated 60 mph is actually 60.8 mph on 245/75R17, and revolutions per mile change from 649 to 641.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 275/65R17

Other comparisons with 245/75R17

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