This started off a while back, when I discovered that the front dérailleur of my commuting steed had seized solid. Despite copious application of freeing agents no way that it would move at all. No surprise really as I almost never change to a smaller cog in commuting, but I like to be able to if, well, just "if". The only option was to strip it completely, grease and rebuild.
So far, so good. I even made a point of changing front cogs at least once per ride. I even remembered to do that for at least three weeks. Then a period went by when I left it, exacerbated by my commuting on the single speed folder. So when I rode on it last week I wasn't entirely surprised to find it had gone back to its old habits. Not quite as bad because if you kicked the mech, it would go to the middle ring. Not the granny ring, but who uses that anyway. Believing that repeated actions should free it, I kept changing down and kicking to get some movement.
So, last Thursday I was in the last mile of my 25 mile commute, within a mile of home. I then discover that if you misplace a kick, your heel can jam the wheel solid while forcing your foot into the mech. I really didn't want to do that, that was not my intention at all, interesting experiment though it was.
So a good few hours of my Sunday afternoon was spent trying to fix the dérailleur. I could adjust it so that the frame of the shifter was free of the chain on the big cog, and it will shift down to the second, but the frame fouled the chain and that was about it.
I don't like it when mechanical things aren't as they should be.