225/75R14 vs 235/70R15

235/70R15 is 0.67 in (16.9 mm) taller than 225/75R14, a +2.44% diameter difference. With the speedometer set for 225/75R14, an indicated 60 mph is 61.5 mph on 235/70R15.

Is this a safe swap?

Diameter difference +2.44%: within the ±3% guideline

By overall diameter alone, 235/70R15 falls inside the ±3% range commonly used as a guideline when replacing 225/75R14. 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.

225/75R14 vs 235/70R15 differences
Measurement	225/75R14	235/70R15	Difference	% diff
Overall diameter	27.29 in (693.1 mm)	27.95 in (710.0 mm)	+0.67 in (+16.9 mm)	+2.44%
Sidewall height	6.64 in (168.8 mm)	6.48 in (164.5 mm)	−0.17 in (−4.2 mm)	−2.52%
Section width	8.86 in (225.0 mm)	9.25 in (235.0 mm)	+0.39 in (+10.0 mm)	+4.44%
Circumference	85.73 in (2,177.4 mm)	87.82 in (2,230.5 mm)	+2.09 in (+53.1 mm)	+2.44%
Revolutions per mile	739	722	−18	−2.38%

True speed with the speedometer calibrated for 225/75R14
Indicated	Actual on 225/75R14	Actual on 235/70R15	Difference
30 mph	30.0 mph	30.7 mph	+0.7 mph
60 mph	60.0 mph	61.5 mph	+1.5 mph
75 mph	75.0 mph	76.8 mph	+1.8 mph

Ride-height change: 235/70R15 raises the vehicle by 0.33 in (8.5 mm) at the axle (half the +16.9 mm diameter difference).

235/70R15 is 0.67 in taller than 225/75R14 and 10 mm wider, a 2.44% difference in overall diameter.

With the speedometer calibrated for 225/75R14, an indicated 60 mph is actually 61.5 mph on 235/70R15, and revolutions per mile change from 739 to 722.

235/70R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 225/75R14.

Size pages

Other comparisons with 225/75R14

Other comparisons with 235/70R15

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