155/70R13 vs 185/60R13

185/60R13 is 0.20 in (5.0 mm) taller than 155/70R13, a +0.91% diameter difference. With the speedometer set for 155/70R13, an indicated 60 mph is 60.5 mph on 185/60R13.

Is this a safe swap?

Diameter difference +0.91%: under 1%

By overall diameter alone, 185/60R13 is a near match for 155/70R13; 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.

155/70R13 vs 185/60R13 differences
Measurement	155/70R13	185/60R13	Difference	% diff
Overall diameter	21.54 in (547.2 mm)	21.74 in (552.2 mm)	+0.20 in (+5.0 mm)	+0.91%
Sidewall height	4.27 in (108.5 mm)	4.37 in (111.0 mm)	+0.10 in (+2.5 mm)	+2.30%
Section width	6.10 in (155.0 mm)	7.28 in (185.0 mm)	+1.18 in (+30.0 mm)	+19.35%
Circumference	67.68 in (1,719.1 mm)	68.30 in (1,734.8 mm)	+0.62 in (+15.7 mm)	+0.91%
Revolutions per mile	936	928	−8	−0.91%

True speed with the speedometer calibrated for 155/70R13
Indicated	Actual on 155/70R13	Actual on 185/60R13	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.7 mph	+0.7 mph

Ride-height change: 185/60R13 raises the vehicle by 0.10 in (2.5 mm) at the axle (half the +5.0 mm diameter difference).

185/60R13 is 0.20 in taller than 155/70R13 and 30 mm wider, a 0.91% difference in overall diameter.

With the speedometer calibrated for 155/70R13, an indicated 60 mph is actually 60.5 mph on 185/60R13, and revolutions per mile change from 936 to 928.

Both sizes mount on 13-inch wheels.

Size pages

Other comparisons with 155/70R13

Other comparisons with 185/60R13

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