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

Tyres started in SAE sizing, then as said, Michelin got into the act. One gets used to anomilies as time goes on. The imperial size is Diameter, not radius, by the way. Its the diameter of the theoretical contact area of tyre to rim.