225/75R15 vs 235/75R15

235/75R15 is 0.59 in (15.0 mm) taller than 225/75R15, a +2.09% diameter difference. With the speedometer set for 225/75R15, an indicated 60 mph is 61.3 mph on 235/75R15.

Is this a safe swap?

Diameter difference +2.09%: within the ±3% guideline

By overall diameter alone, 235/75R15 falls inside the ±3% range commonly used as a guideline when replacing 225/75R15. 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.

225/75R15 vs 235/75R15 differences
Measurement	225/75R15	235/75R15	Difference	% diff
Overall diameter	28.29 in (718.5 mm)	28.88 in (733.5 mm)	+0.59 in (+15.0 mm)	+2.09%
Sidewall height	6.64 in (168.8 mm)	6.94 in (176.3 mm)	+0.30 in (+7.5 mm)	+4.44%
Section width	8.86 in (225.0 mm)	9.25 in (235.0 mm)	+0.39 in (+10.0 mm)	+4.44%
Circumference	88.87 in (2,257.2 mm)	90.72 in (2,304.4 mm)	+1.86 in (+47.1 mm)	+2.09%
Revolutions per mile	713	698	−15	−2.04%

True speed with the speedometer calibrated for 225/75R15
Indicated	Actual on 225/75R15	Actual on 235/75R15	Difference
30 mph	30.0 mph	30.6 mph	+0.6 mph
60 mph	60.0 mph	61.3 mph	+1.3 mph
75 mph	75.0 mph	76.6 mph	+1.6 mph

Ride-height change: 235/75R15 raises the vehicle by 0.30 in (7.5 mm) at the axle (half the +15.0 mm diameter difference).

235/75R15 is 0.59 in taller than 225/75R15 and 10 mm wider, a 2.09% difference in overall diameter.

With the speedometer calibrated for 225/75R15, an indicated 60 mph is actually 61.3 mph on 235/75R15, and revolutions per mile change from 713 to 698.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 225/75R15

Other comparisons with 235/75R15

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