205/75R15 vs 225/70R15

225/70R15 is 0.30 in (7.5 mm) taller than 205/75R15, a +1.09% diameter difference. With the speedometer set for 205/75R15, an indicated 60 mph is 60.7 mph on 225/70R15.

Is this a safe swap?

Diameter difference +1.09%: within the ±3% guideline

By overall diameter alone, 225/70R15 falls inside the ±3% range commonly used as a guideline when replacing 205/75R15. 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.

205/75R15 vs 225/70R15 differences
Measurement	205/75R15	225/70R15	Difference	% diff
Overall diameter	27.11 in (688.5 mm)	27.40 in (696.0 mm)	+0.30 in (+7.5 mm)	+1.09%
Sidewall height	6.05 in (153.8 mm)	6.20 in (157.5 mm)	+0.15 in (+3.8 mm)	+2.44%
Section width	8.07 in (205.0 mm)	8.86 in (225.0 mm)	+0.79 in (+20.0 mm)	+9.76%
Circumference	85.16 in (2,163.0 mm)	86.08 in (2,186.5 mm)	+0.93 in (+23.6 mm)	+1.09%
Revolutions per mile	744	736	−8	−1.08%

True speed with the speedometer calibrated for 205/75R15
Indicated	Actual on 205/75R15	Actual on 225/70R15	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.7 mph	+0.7 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 225/70R15 raises the vehicle by 0.15 in (3.8 mm) at the axle (half the +7.5 mm diameter difference).

225/70R15 is 0.30 in taller than 205/75R15 and 20 mm wider, a 1.09% difference in overall diameter.

With the speedometer calibrated for 205/75R15, an indicated 60 mph is actually 60.7 mph on 225/70R15, and revolutions per mile change from 744 to 736.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 205/75R15

Other comparisons with 225/70R15

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