system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Car tire dimensions, why oh why 205/55/16.

Why is a tire's dimension described using inches, millimeters and percentage? Is it to annoy ppl or to make the believers of the imperial and metric system happy, all at once?
gpt
It's basically because early on the US dominated auto manufacturing so wheels got to be measured in inches.

Later on Europe dominated tire manufacturing, cause of the introduction of radial tires from Michelin.

One hitch was added in because the US ended up requiring inch rim sizes in different regulations so to sell in the US tires had to be marked with the inch sizing.

The aspect ratio seems like it's thrown in to mess with you even more. However the aspect ratio is meant to convey performance changes from wider tires. This doesn't scale with an absolute width though. The same width in a small tire performs different than that of a big tire. So we get a ratio instead.


And so now we have different measurements and no one really wants to bother having two systems in place for like a decade of transition to make it more consistent.