175/70R14 vs 205/55R15

205/55R15 is 0.23 in (5.9 mm) taller than 175/70R14, a +0.98% diameter difference. With the speedometer set for 175/70R14, an indicated 60 mph is 60.6 mph on 205/55R15.

Is this a safe swap?

Diameter difference +0.98%: under 1%

By overall diameter alone, 205/55R15 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 205/55R15 differences
Measurement	175/70R14	205/55R15	Difference	% diff
Overall diameter	23.65 in (600.6 mm)	23.88 in (606.5 mm)	+0.23 in (+5.9 mm)	+0.98%
Sidewall height	4.82 in (122.5 mm)	4.44 in (112.8 mm)	−0.38 in (−9.7 mm)	−7.96%
Section width	6.89 in (175.0 mm)	8.07 in (205.0 mm)	+1.18 in (+30.0 mm)	+17.14%
Circumference	74.29 in (1,886.8 mm)	75.01 in (1,905.4 mm)	+0.73 in (+18.5 mm)	+0.98%
Revolutions per mile	853	845	−8	−0.97%

True speed with the speedometer calibrated for 175/70R14
Indicated	Actual on 175/70R14	Actual on 205/55R15	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.6 mph	+0.6 mph
75 mph	75.0 mph	75.7 mph	+0.7 mph

Ride-height change: 205/55R15 raises the vehicle by 0.12 in (3.0 mm) at the axle (half the +5.9 mm diameter difference).

205/55R15 is 0.23 in taller than 175/70R14 and 30 mm wider, a 0.98% difference in overall diameter.

With the speedometer calibrated for 175/70R14, an indicated 60 mph is actually 60.6 mph on 205/55R15, and revolutions per mile change from 853 to 845.

205/55R15 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 205/55R15

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