175/70R14 vs 225/50R15

225/50R15 is 0.21 in (5.4 mm) taller than 175/70R14, a +0.90% diameter difference. With the speedometer set for 175/70R14, an indicated 60 mph is 60.5 mph on 225/50R15.

Is this a safe swap?

Diameter difference +0.90%: under 1%

By overall diameter alone, 225/50R15 is a near match for 175/70R14; 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.

175/70R14 vs 225/50R15 differences
Measurement	175/70R14	225/50R15	Difference	% diff
Overall diameter	23.65 in (600.6 mm)	23.86 in (606.0 mm)	+0.21 in (+5.4 mm)	+0.90%
Sidewall height	4.82 in (122.5 mm)	4.43 in (112.5 mm)	−0.39 in (−10.0 mm)	−8.16%
Section width	6.89 in (175.0 mm)	8.86 in (225.0 mm)	+1.97 in (+50.0 mm)	+28.57%
Circumference	74.29 in (1,886.8 mm)	74.95 in (1,903.8 mm)	+0.67 in (+17.0 mm)	+0.90%
Revolutions per mile	853	845	−8	−0.89%

True speed with the speedometer calibrated for 175/70R14
Indicated	Actual on 175/70R14	Actual on 225/50R15	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.7 mph	+0.7 mph

Ride-height change: 225/50R15 raises the vehicle by 0.11 in (2.7 mm) at the axle (half the +5.4 mm diameter difference).

225/50R15 is 0.21 in taller than 175/70R14 and 50 mm wider, a 0.90% difference in overall diameter.

With the speedometer calibrated for 175/70R14, an indicated 60 mph is actually 60.5 mph on 225/50R15, and revolutions per mile change from 853 to 845.

225/50R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 175/70R14.

Size pages

Other comparisons with 175/70R14

Other comparisons with 225/50R15

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