155/80R14 vs 225/50R15

225/50R15 is 0.09 in (2.4 mm) taller than 155/80R14, a +0.40% diameter difference. With the speedometer set for 155/80R14, an indicated 60 mph is 60.2 mph on 225/50R15.

Is this a safe swap?

Diameter difference +0.40%: under 1%

By overall diameter alone, 225/50R15 is a near match for 155/80R14; 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.

155/80R14 vs 225/50R15 differences
Measurement	155/80R14	225/50R15	Difference	% diff
Overall diameter	23.76 in (603.6 mm)	23.86 in (606.0 mm)	+0.09 in (+2.4 mm)	+0.40%
Sidewall height	4.88 in (124.0 mm)	4.43 in (112.5 mm)	−0.45 in (−11.5 mm)	−9.27%
Section width	6.10 in (155.0 mm)	8.86 in (225.0 mm)	+2.76 in (+70.0 mm)	+45.16%
Circumference	74.66 in (1,896.3 mm)	74.95 in (1,903.8 mm)	+0.30 in (+7.5 mm)	+0.40%
Revolutions per mile	849	845	−3	−0.40%

True speed with the speedometer calibrated for 155/80R14
Indicated	Actual on 155/80R14	Actual on 225/50R15	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.2 mph	+0.2 mph
75 mph	75.0 mph	75.3 mph	+0.3 mph

Ride-height change: 225/50R15 raises the vehicle by 0.05 in (1.2 mm) at the axle (half the +2.4 mm diameter difference).

225/50R15 is 0.09 in taller than 155/80R14 and 70 mm wider, a 0.40% difference in overall diameter.

With the speedometer calibrated for 155/80R14, an indicated 60 mph is actually 60.2 mph on 225/50R15, and revolutions per mile change from 849 to 845.

225/50R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 155/80R14.

Size pages

Other comparisons with 155/80R14

Other comparisons with 225/50R15

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