TireSizesFinder

225/50R15 vs 205/55R15

205/55R15 is 0.02 in (0.5 mm) taller than 225/50R15, a +0.08% diameter difference. With the speedometer set for 225/50R15, an indicated 60 mph is 60.0 mph on 205/55R15.

Is this a safe swap?

Diameter difference +0.08%: under 1%

By overall diameter alone, 205/55R15 is a near match for 225/50R15; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 225/50R15 (23.86 in) vs 205/55R15 (23.88 in)225/50R1523.86 in × 8.86 in205/55R1523.88 in × 8.07 in
Side profile and tread width, drawn to the same scale.
225/50R15 vs 205/55R15 differences
Measurement225/50R15205/55R15Difference% diff
Overall diameter23.86 in (606.0 mm)23.88 in (606.5 mm)+0.02 in (+0.5 mm)+0.08%
Sidewall height4.43 in (112.5 mm)4.44 in (112.8 mm)+0.01 in (+0.3 mm)+0.22%
Section width8.86 in (225.0 mm)8.07 in (205.0 mm)−0.79 in (−20.0 mm)−8.89%
Circumference74.95 in (1,903.8 mm)75.01 in (1,905.4 mm)+0.06 in (+1.6 mm)+0.08%
Revolutions per mile845845−1−0.08%
True speed with the speedometer calibrated for 225/50R15
IndicatedActual on 225/50R15Actual on 205/55R15Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.1 mph+0.1 mph

Ride-height change: 205/55R15 raises the vehicle by 0.01 in (0.3 mm) at the axle (half the +0.5 mm diameter difference).

205/55R15 is 0.02 in taller than 225/50R15 and 20 mm narrower, a 0.08% difference in overall diameter.

With the speedometer calibrated for 225/50R15, an indicated 60 mph is actually 60.0 mph on 205/55R15, and revolutions per mile change from 845 to 845.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 225/50R15

Other comparisons with 205/55R15

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.