155/70R12
Overall diameter 521.8 mm
155/70R12 — 521.8 mm tall, and what it swaps with
155/70R12 is 155 mm wide with a 70% sidewall on a 12-inch wheel. That sidewall is 108.5 mm, so the tyre stands 521.8 mm tall and turns 610 times per kilometre.
- Section width
- 155 mm
- Aspect ratio
- 70 %
- Wheel size
- 12 in (304.8 mm)
- Sidewall height
- 108.5 mm
- Overall diameter
- 521.8 mm (20.54 in)
- Circumference
- 1639.3 mm
- Turns per km
- 610
Sizes you can swap to
Only sizes whose overall diameter stays within 3% are listed. A different diameter covers a different distance per turn, and that gap becomes speedometer error.
Other sizes for this wheel
12-inch wheels
How the code reads
The 205 is millimetres, the 55 is a percentage of that width, and only the 16 is inches. The R stands for radial construction.
How to read this
- The first three digits are the width in mm, the middle two are the aspect ratio in percent, the last two the wheel in inches.
- Sidewall height = width × aspect ÷ 100. For 205/55 that is 112.75 mm.
- Overall diameter = wheel diameter + twice the sidewall. A 16-inch wheel is 406.4 mm.
- Once the diameter shifts by more than 3%, the speedometer and odometer drift by the same amount.
Frequently asked questions
Q. What is the overall diameter of 155/70R12?
521.8 mm — the 304.8 mm wheel plus the 108.5 mm sidewall at top and bottom.
Q. How many turns per kilometre does 155/70R12 make?
Its circumference is 1639.3 mm, so 610 turns.
Q. What can I swap it for?
Nothing in this table comes close enough.
Q. Why is the sidewall 108.5 mm?
Because it is 70% of the 155 mm width. The aspect ratio is a proportion of the width, not a length.