[ is it displays? ] -yes-> [ inches ]
↓ no
[ is it screws? ] -yes-> [ inches ]
↓ no
[ is it tires? ] -yes-> [ inches ]
↓ no
[is if flight altitude? ] -yes-> [ feet ]
↓ no
[ metric ]
Even in the US we use metric tire sizing apart from a select few offload tires, which is annoying because its not even actual dimensions but more of a ratio or percentage of the overall width of the tire (in addition to the wheel size being in inches as you mentioned).
[ is it displays? ] -yes-> [ inches ] ↓ no [ is it screws? ] -yes-> [ inches ] ↓ no [ is it tires? ] -yes-> [ inches ] ↓ no [is if flight altitude? ] -yes-> [ feet ] ↓ no [ metric ]FTFY
both for car and light truck tires. inches for wheel diameter, millimeters for tread width,
Even in the US we use metric tire sizing apart from a select few offload tires, which is annoying because its not even actual dimensions but more of a ratio or percentage of the overall width of the tire (in addition to the wheel size being in inches as you mentioned).
Also, floppy disks.
Road bike tires? Metric. Mtb tires? Imperial. Car tire inner diameter? Imperial. Car tire width? Metric.
Car tire height? Neither. Fun fact.
I agree on the tires, but at least in Germany, we measure flight altitude in meters.
And if you don’t know for sure you can always default to a “Saarlands”