What does 205/55R16 mean?
It's three measurements in one code: 205 mm wide, sidewall 55% of that width, on a 16-inch rim. Total wheel diameter: about 63.2 cm. Here's each part.
The code, piece by piece
| Part | Meaning | In this tire |
|---|---|---|
| 205 | Tire width in mm | 205 mm (20.5 cm) |
| 55 | Aspect ratio: sidewall height as % of width | 55% of 205 = 112.8 mm |
| R | Radial construction (virtually all modern tires) | Radial |
| 16 | Rim diameter in inches | 16" (40.6 cm) |
What that adds up to
Total diameter = rim + two sidewalls = 406.4 mm + 2 × 112.8 mm = 631.9 mm (63.2 cm). That diameter is what matters when changing sizes — it drives your speedometer, gearing and clearance.
After the size you'll see more codes, like 91V: 91 is the load index (615 kg per tire) and V the speed rating (up to 240 km/h). When replacing tires, match or exceed both — it's a legal and insurance requirement in many countries.
Frequently asked questions
What does the 205 mean in a tire size?
The tire's width in millimetres — 205 mm, about 20.5 cm.
What does the 55 mean in 205/55R16?
The aspect ratio: the sidewall height is 55% of the width, so 112.8 mm.
What does the R mean in tire sizes?
Radial construction — the standard for virtually all modern car tires.