175/55R15 vs 195/50R15

195/50R15 is 0.10 in (2.5 mm) taller than 175/55R15, a +0.44% diameter difference. With the speedometer set for 175/55R15, an indicated 60 mph is 60.3 mph on 195/50R15.

Is this a safe swap?

Diameter difference +0.44%: under 1%

By overall diameter alone, 195/50R15 is a near match for 175/55R15; 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.

175/55R15 vs 195/50R15 differences
Measurement	175/55R15	195/50R15	Difference	% diff
Overall diameter	22.58 in (573.5 mm)	22.68 in (576.0 mm)	+0.10 in (+2.5 mm)	+0.44%
Sidewall height	3.79 in (96.3 mm)	3.84 in (97.5 mm)	+0.05 in (+1.3 mm)	+1.30%
Section width	6.89 in (175.0 mm)	7.68 in (195.0 mm)	+0.79 in (+20.0 mm)	+11.43%
Circumference	70.93 in (1,801.7 mm)	71.24 in (1,809.6 mm)	+0.31 in (+7.9 mm)	+0.44%
Revolutions per mile	893	889	−4	−0.43%

True speed with the speedometer calibrated for 175/55R15
Indicated	Actual on 175/55R15	Actual on 195/50R15	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.3 mph	+0.3 mph
75 mph	75.0 mph	75.3 mph	+0.3 mph

Ride-height change: 195/50R15 raises the vehicle by 0.05 in (1.3 mm) at the axle (half the +2.5 mm diameter difference).

195/50R15 is 0.10 in taller than 175/55R15 and 20 mm wider, a 0.44% difference in overall diameter.

With the speedometer calibrated for 175/55R15, an indicated 60 mph is actually 60.3 mph on 195/50R15, and revolutions per mile change from 893 to 889.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 175/55R15

Other comparisons with 195/50R15

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