175/70R14 vs 185/60R15

185/60R15 is 0.09 in (2.4 mm) taller than 175/70R14, a +0.40% diameter difference. With the speedometer set for 175/70R14, an indicated 60 mph is 60.2 mph on 185/60R15.

Is this a safe swap?

Diameter difference +0.40%: under 1%

By overall diameter alone, 185/60R15 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 185/60R15 differences
Measurement	175/70R14	185/60R15	Difference	% diff
Overall diameter	23.65 in (600.6 mm)	23.74 in (603.0 mm)	+0.09 in (+2.4 mm)	+0.40%
Sidewall height	4.82 in (122.5 mm)	4.37 in (111.0 mm)	−0.45 in (−11.5 mm)	−9.39%
Section width	6.89 in (175.0 mm)	7.28 in (185.0 mm)	+0.39 in (+10.0 mm)	+5.71%
Circumference	74.29 in (1,886.8 mm)	74.58 in (1,894.4 mm)	+0.30 in (+7.5 mm)	+0.40%
Revolutions per mile	853	850	−3	−0.40%

True speed with the speedometer calibrated for 175/70R14
Indicated	Actual on 175/70R14	Actual on 185/60R15	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: 185/60R15 raises the vehicle by 0.05 in (1.2 mm) at the axle (half the +2.4 mm diameter difference).

185/60R15 is 0.09 in taller than 175/70R14 and 10 mm wider, a 0.40% difference in overall diameter.

With the speedometer calibrated for 175/70R14, an indicated 60 mph is actually 60.2 mph on 185/60R15, and revolutions per mile change from 853 to 850.

185/60R15 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 185/60R15

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