It really makes you wonder when the head of the RCTA can not tell the difference between a nut and a bolt.
Terminology in that piece is used correctly, but it's terse because it's an exact copy of the anonymous note that was sent round the bike industry a few days previously - so the assumption is that those reading would be familiar with the equipment in question, recent double-pivot caliper brakes for road racing bikes.
I tried to explain it a bit more extensively in my piece on Cyclingnews; I'm happy to learn that I seem to have managed to do so.
