It's the jargon, you see. It eludes you every time.
Last time I bought bike tyres I'm pretty sure I went up to a big rack of them, chose the ones I wanted, found the inner tubes and swanned off with them. I didn't have to worry about anything. It was self-service in the megamarket.
This time it was different. Still clutching my new carte de séjour I entered the pneuerie.
"Hallo, I need to buy two pneus."
"Hi. OK, what size?"
(Aha - I had looked this up, so I knew, and because the numbers were odd I had stored them on my phone)
"Let me look : it's 47 x 559."
The pneumonger rubbed his chin and frowned.
"We haven't got that. What sort of bike is it?"
I described the bike.
"This might be close."
He got down a 26" x 1.75". There, embossed on the side was ... 47 x 559.
"Oh! There we go! It's this one."
"We don't use metric?"
"No, we use inches."
"I also need the chambres."
"No problem." Out came two lovely inner tubes in nice Michelin boxes.
"What about the ruban?" (This one I was guessing.)
"Sorry, we don't have that. We have this kind of self-adhesive tape now, but you can't sell it, it comes in huge rolls."
"But that's what it's called, right?"
"No, it's called the fond de jant. If I were you I'd just look it over and if it's OK leave it."
"You know what? By next time I need some I'll have forgotten fond de jant and I'll call it the ruban again."
"It's not a problem. Anyone would know what you meant."