235/75R15 vs 245/75R15

245/75R15 is 0.59 in (15.0 mm) taller than 235/75R15, a +2.04% diameter difference. With the speedometer set for 235/75R15, an indicated 60 mph is 61.2 mph on 245/75R15.

Is this a safe swap?

Diameter difference +2.04%: within the ±3% guideline

By overall diameter alone, 245/75R15 falls inside the ±3% range commonly used as a guideline when replacing 235/75R15. 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.

235/75R15 vs 245/75R15 differences
Measurement	235/75R15	245/75R15	Difference	% diff
Overall diameter	28.88 in (733.5 mm)	29.47 in (748.5 mm)	+0.59 in (+15.0 mm)	+2.04%
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	90.72 in (2,304.4 mm)	92.58 in (2,351.5 mm)	+1.86 in (+47.1 mm)	+2.04%
Revolutions per mile	698	684	−14	−2.00%

True speed with the speedometer calibrated for 235/75R15
Indicated	Actual on 235/75R15	Actual on 245/75R15	Difference
30 mph	30.0 mph	30.6 mph	+0.6 mph
60 mph	60.0 mph	61.2 mph	+1.2 mph
75 mph	75.0 mph	76.5 mph	+1.5 mph

Ride-height change: 245/75R15 raises the vehicle by 0.30 in (7.5 mm) at the axle (half the +15.0 mm diameter difference).

245/75R15 is 0.59 in taller than 235/75R15 and 10 mm wider, a 2.04% difference in overall diameter.

With the speedometer calibrated for 235/75R15, an indicated 60 mph is actually 61.2 mph on 245/75R15, and revolutions per mile change from 698 to 684.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 235/75R15

Other comparisons with 245/75R15

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