225/75R14 vs 225/70R15

225/70R15 is 0.11 in (2.9 mm) taller than 225/75R14, a +0.42% diameter difference. With the speedometer set for 225/75R14, an indicated 60 mph is 60.3 mph on 225/70R15.

Is this a safe swap?

Diameter difference +0.42%: under 1%

By overall diameter alone, 225/70R15 is a near match for 225/75R14; the speedometer changes by less than 1%. 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 225/70R15 differences
Measurement	225/75R14	225/70R15	Difference	% diff
Overall diameter	27.29 in (693.1 mm)	27.40 in (696.0 mm)	+0.11 in (+2.9 mm)	+0.42%
Sidewall height	6.64 in (168.8 mm)	6.20 in (157.5 mm)	−0.44 in (−11.2 mm)	−6.67%
Section width	8.86 in (225.0 mm)	8.86 in (225.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	85.73 in (2,177.4 mm)	86.08 in (2,186.5 mm)	+0.36 in (+9.1 mm)	+0.42%
Revolutions per mile	739	736	−3	−0.42%

True speed with the speedometer calibrated for 225/75R14
Indicated	Actual on 225/75R14	Actual on 225/70R15	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.3 mph	+0.3 mph
75 mph	75.0 mph	75.3 mph	+0.3 mph

Ride-height change: 225/70R15 raises the vehicle by 0.06 in (1.5 mm) at the axle (half the +2.9 mm diameter difference).

225/70R15 is 0.11 in taller than 225/75R14 and the same width, a 0.42% difference in overall diameter.

With the speedometer calibrated for 225/75R14, an indicated 60 mph is actually 60.3 mph on 225/70R15, and revolutions per mile change from 739 to 736.

225/70R15 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 225/70R15

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