185/70R13 vs 195/50R15

195/50R15 is 0.52 in (13.2 mm) shorter than 185/70R13, a −2.24% diameter difference. With the speedometer set for 185/70R13, an indicated 60 mph is 58.7 mph on 195/50R15.

Is this a safe swap?

Diameter difference −2.24%: within the ±3% guideline

By overall diameter alone, 195/50R15 falls inside the ±3% range commonly used as a guideline when replacing 185/70R13. 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.

185/70R13 vs 195/50R15 differences
Measurement	185/70R13	195/50R15	Difference	% diff
Overall diameter	23.20 in (589.2 mm)	22.68 in (576.0 mm)	−0.52 in (−13.2 mm)	−2.24%
Sidewall height	5.10 in (129.5 mm)	3.84 in (97.5 mm)	−1.26 in (−32.0 mm)	−24.71%
Section width	7.28 in (185.0 mm)	7.68 in (195.0 mm)	+0.39 in (+10.0 mm)	+5.41%
Circumference	72.88 in (1,851.0 mm)	71.24 in (1,809.6 mm)	−1.63 in (−41.5 mm)	−2.24%
Revolutions per mile	869	889	+20	+2.29%

True speed with the speedometer calibrated for 185/70R13
Indicated	Actual on 185/70R13	Actual on 195/50R15	Difference
30 mph	30.0 mph	29.3 mph	−0.7 mph
60 mph	60.0 mph	58.7 mph	−1.3 mph
75 mph	75.0 mph	73.3 mph	−1.7 mph

Ride-height change: 195/50R15 lowers the vehicle by 0.26 in (6.6 mm) at the axle (half the −13.2 mm diameter difference).

195/50R15 is 0.52 in shorter than 185/70R13 and 10 mm wider, a 2.24% difference in overall diameter.

With the speedometer calibrated for 185/70R13, an indicated 60 mph is actually 58.7 mph on 195/50R15, and revolutions per mile change from 869 to 889.

195/50R15 mounts on a 15-inch wheel, a plus-2 fitment from the 13-inch wheel of 185/70R13.

Size pages

Other comparisons with 185/70R13

Other comparisons with 195/50R15

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