Eli5: how come tires use marking from different measurement system. Metric for the width, imperial for radius and percentage for height? (like 205/50 R16)

Question

Eli5: how come tires use marking from different measurement system. Metric for the width, imperial for radius and percentage for height? (like 205/50 R16)

In: 422

Answer 1

R16 refers to the 16″ wheel size, not the tire’s radius. The ***/50 is the ratio of the sidewall height to the tread width. A 205/50 has a sidewall height of 102.5mm.