185/60-R15
People saying they don't understand metric units does remind me a little of the English (sic) tourist shouting ever more loudly in English at the foreign shop keeper.
Many years ago in my first proper job I had to work out moments of inertia of engineering assemblies, and the manager wanted it in imperial units.
"Slug.ft squared" anyone? No, I didn't think so.
(1 Slug = 32.2 lbs mass .................. don't ask ...............)
I have to confess, however, that I still think of small clearances in "thous", I know what 2 thou clearance is like, I still have to think twice about 50 microns.
Fuel consumption is an interesting one. It depends whether you want to know how far you can go on the fuel you have, or whether you want to know how much fuel you need to get where you want to go.