Sorry no, this not true anymore here in Europe since more than 25 years! We used to employ tires with inches numbers, but now all tyres, both for cars and motorbikes, are in mm..Tires are also in inches world wide as well.
There was a time in the early 80s they tried to make an all metric tire, Michelin TRX comes to mind. It didn't work and inches are still the standard for tire sizes.
In fact, I own several vintage motorbikes, and finding tires with proper measures in inches is quite difficult nowadays; here my bikes:
Fantic Motor Photo Gallery
Yamaha Photo Gallery
For both collections the early ones are in inches, the last two of each collection are already in mm.
So the year it changed is 1991, more or less.