Question 1

Which tire is taller, 155/70 R13 or 145/70 R13?

Accepted Answer

155/70 R13 is taller by 14.0 mm (2.56%) compared with 145/70 R13.

Question 2

What is the diameter difference between 155/70 R13 and 145/70 R13?

Accepted Answer

155/70 R13 measures 547 mm overall diameter, 145/70 R13 measures 533 mm — a difference of 14.0 mm (2.56%).

Question 3

How much speedometer error does this change create?

Accepted Answer

Switching from 155/70 R13 to 145/70 R13 changes the speedometer reading by -2.56%. At an indicated 100 km/h, your true speed becomes about 97.4 km/h.

Question 4

Is 145/70 R13 a safe replacement for 155/70 R13?

Accepted Answer

Within ±3% diameter — generally considered a safe replacement from a speedometer-error standpoint, provided wheel offset, rim width and clearance also match your vehicle.

Question 5

What else should I check before changing tire size?

Accepted Answer

Beyond diameter and speedometer error, verify wheel offset (ET), rim width, hub bore, load index, brake and suspension clearance, and your vehicle's manufacturer specification. Local regulations may also limit how far you can deviate from OEM.

Metric	155/70 R13	145/70 R13	Difference
Overall diameter	547.2 mm	533.2 mm	-14.0 mm (-2.56%)
Sidewall height	108.5 mm	101.5 mm	-7.0 mm
Circumference	1.719 m	1.675 m	-44.0 mm
Revs / km	581.7	597.0	+15.3
Ground clearance	reference	-7.0 mm	-7.0 mm
Speedometer @ 100 km/h	100.0 km/h	97.4 km/h	-2.56 km/h

155/70 R13 vs 145/70 R13

Detailed comparison

Verdict: excellent

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