165/70R13 vs 145/80R13

145/80R13 is 0.04 in (1.0 mm) taller than 165/70R13, a +0.18% diameter difference. With the speedometer set for 165/70R13, an indicated 60 mph is 60.1 mph on 145/80R13.

Is this a safe swap?

Diameter difference +0.18%: under 1%

By overall diameter alone, 145/80R13 is a near match for 165/70R13; 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.

165/70R13 vs 145/80R13 differences
Measurement	165/70R13	145/80R13	Difference	% diff
Overall diameter	22.09 in (561.2 mm)	22.13 in (562.2 mm)	+0.04 in (+1.0 mm)	+0.18%
Sidewall height	4.55 in (115.5 mm)	4.57 in (116.0 mm)	+0.02 in (+0.5 mm)	+0.43%
Section width	6.50 in (165.0 mm)	5.71 in (145.0 mm)	−0.79 in (−20.0 mm)	−12.12%
Circumference	69.41 in (1,763.1 mm)	69.54 in (1,766.2 mm)	+0.12 in (+3.1 mm)	+0.18%
Revolutions per mile	913	911	−2	−0.18%

True speed with the speedometer calibrated for 165/70R13
Indicated	Actual on 165/70R13	Actual on 145/80R13	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.1 mph	+0.1 mph
75 mph	75.0 mph	75.1 mph	+0.1 mph

Ride-height change: 145/80R13 raises the vehicle by 0.02 in (0.5 mm) at the axle (half the +1.0 mm diameter difference).

145/80R13 is 0.04 in taller than 165/70R13 and 20 mm narrower, a 0.18% difference in overall diameter.

With the speedometer calibrated for 165/70R13, an indicated 60 mph is actually 60.1 mph on 145/80R13, and revolutions per mile change from 913 to 911.

Both sizes mount on 13-inch wheels.

Size pages

Other comparisons with 165/70R13

Other comparisons with 145/80R13

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