235/75R17 vs 245/75R17

245/75R17 is 0.59 in (15.0 mm) taller than 235/75R17, a +1.91% diameter difference. With the speedometer set for 235/75R17, an indicated 60 mph is 61.1 mph on 245/75R17.

Is this a safe swap?

Diameter difference +1.91%: within the ±3% guideline

By overall diameter alone, 245/75R17 falls inside the ±3% range commonly used as a guideline when replacing 235/75R17. 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.

235/75R17 vs 245/75R17 differences
Measurement	235/75R17	245/75R17	Difference	% diff
Overall diameter	30.88 in (784.3 mm)	31.47 in (799.3 mm)	+0.59 in (+15.0 mm)	+1.91%
Sidewall height	6.94 in (176.3 mm)	7.23 in (183.8 mm)	+0.30 in (+7.5 mm)	+4.26%
Section width	9.25 in (235.0 mm)	9.65 in (245.0 mm)	+0.39 in (+10.0 mm)	+4.26%
Circumference	97.01 in (2,464.0 mm)	98.86 in (2,511.1 mm)	+1.86 in (+47.1 mm)	+1.91%
Revolutions per mile	653	641	−12	−1.88%

True speed with the speedometer calibrated for 235/75R17
Indicated	Actual on 235/75R17	Actual on 245/75R17	Difference
30 mph	30.0 mph	30.6 mph	+0.6 mph
60 mph	60.0 mph	61.1 mph	+1.1 mph
75 mph	75.0 mph	76.4 mph	+1.4 mph

Ride-height change: 245/75R17 raises the vehicle by 0.30 in (7.5 mm) at the axle (half the +15.0 mm diameter difference).

245/75R17 is 0.59 in taller than 235/75R17 and 10 mm wider, a 1.91% difference in overall diameter.

With the speedometer calibrated for 235/75R17, an indicated 60 mph is actually 61.1 mph on 245/75R17, and revolutions per mile change from 653 to 641.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 235/75R17

Other comparisons with 245/75R17

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