Metric System in Canada

DrewE wrote:
Aren't you glad that modern tires are sized using one metric measurement (the tread width), one imperial measurement (the wheel diameter), and one unitless quantity (the aspect ratio)? Otherwise, you'd have to change the tires when you change the air; putting metric air in inch tires would cause all sorts of problems.

Aspect ratio is not unitless its just that a ratio. its the sidewall height based on a percentage of the tires width.