22:45 Oct 20 

those "V" treads on tractors had to go a particular way round. As you intimate though, bus tyres may well not be radials.

22:42 Oct 20 

But I wonder if bus tyres actually are radials, even in this day and age?

I know that some tractor wheels are made symmetrical, so all you have to do is simply turn the wheels round, instead of going to all the effort of removing and refitting the actual tyres.

19:23 Oct 20 

Radials should not be turned so as to rotate the other way.

16:57 Oct 20 

Your own reference below actually explains it:

« Le retour sur jante consiste à démonter le pneu et à le retourner sur SA ROUE »

BUT 'return' doesn't mean 'return' here, but 'turn' — it's common practice (or was, till 'handed' tyres came in!) to turn tyres round on their rims in order to even out side-to-side wear.

Your ref. actually says that "turning on the rim means removing the tyre and turning it round on its wheel"; there would be little point in going to all the trouble of removing the tyre if you then simply fitted it back on again!