Just over a year ago I bought a new bike (a Giant Escape 3) with a trigger gear system - my previous one had a grip-twist to change gears.
After riding and experimenting for a while, I was able to determine that the trigger down didn't shift a single gear - it changed down two. This behaviour is consistent as far as I can tell: it does it every single time I've thought to check, whatever gear I'm in. The trigger up does increment a single gear as expected.
It's just something I've learned to ride with: it's not entirely inconvenient in traffic when you're stopping frequently at lights. But lately, I got to wondering whether it was, in fact, a "feature" or a "bug"?
If it is a fault, how can I fix it?