145/70R12 tire size

A 145/70R12 tire is 19.99 inches (507.8 mm) tall, 5.71 in (145 mm) wide and fits a 12-inch wheel. In inch notation it is roughly a 20.0x5.7R12.

Compare 145/70R12 with another size

Current size

New size

Speed in mphkm/h

−0.51%

60 mph on the speedometer = 59.7 mph actual

Within the ±3 % diameter range most tire fitters accept.

145/70R12 175/50R13

	Current	New	Difference	%
Diameter	19.99 in	19.89 in	−0.10 in	−0.51%
Diameter	507.8 mm	505.2 mm	−2.6 mm	−0.51%
Width	5.71 in	6.89 in	+1.18 in	+20.69%
Width	145.0 mm	175.0 mm	+30.0 mm	+20.69%
Sidewall	4.00 in	3.44 in	−0.55 in	−13.79%
Sidewall	101.5 mm	87.5 mm	−14.0 mm	−13.79%
Circumference	62.81 in	62.49 in	−0.32 in	−0.51%
Revs per mile	1,008.8	1,014.0	+5.2	+0.51%

Size	Wheel	Diameter	Difference
175/50R13	Plus 1 (13 in)	19.89 in	−0.51%
165/55R13	Plus 1 (13 in)	20.15 in	+0.77%
175/55R13	Plus 1 (13 in)	20.58 in	+2.93%

145 — section width in millimetres (5.71 in).
70 — aspect ratio: the sidewall is 70 % of the width, 101.5 mm.
R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
12 — fits a 12-inch diameter wheel.

The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.