185/70R13 vs 165/80R13

165/80R13 is 0.20 in (5.0 mm) taller than 185/70R13, a +0.85% diameter difference. With the speedometer set for 185/70R13, an indicated 60 mph is 60.5 mph on 165/80R13.

Is this a safe swap?

Diameter difference +0.85%: under 1%

By overall diameter alone, 165/80R13 is a near match for 185/70R13; 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.

185/70R13 vs 165/80R13 differences
Measurement	185/70R13	165/80R13	Difference	% diff
Overall diameter	23.20 in (589.2 mm)	23.39 in (594.2 mm)	+0.20 in (+5.0 mm)	+0.85%
Sidewall height	5.10 in (129.5 mm)	5.20 in (132.0 mm)	+0.10 in (+2.5 mm)	+1.93%
Section width	7.28 in (185.0 mm)	6.50 in (165.0 mm)	−0.79 in (−20.0 mm)	−10.81%
Circumference	72.88 in (1,851.0 mm)	73.49 in (1,866.7 mm)	+0.62 in (+15.7 mm)	+0.85%
Revolutions per mile	869	862	−7	−0.84%

True speed with the speedometer calibrated for 185/70R13
Indicated	Actual on 185/70R13	Actual on 165/80R13	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	75.6 mph	+0.6 mph

Ride-height change: 165/80R13 raises the vehicle by 0.10 in (2.5 mm) at the axle (half the +5.0 mm diameter difference).

165/80R13 is 0.20 in taller than 185/70R13 and 20 mm narrower, a 0.85% difference in overall diameter.

With the speedometer calibrated for 185/70R13, an indicated 60 mph is actually 60.5 mph on 165/80R13, and revolutions per mile change from 869 to 862.

Both sizes mount on 13-inch wheels.

Size pages

Other comparisons with 185/70R13

Other comparisons with 165/80R13

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