Originally Posted by
Drew Eckhardt
1)
To speculate on how this leads to load dependent shifting: maybe your rear triangle moves a bit under heavy load and the derailleur spring is stiffer than the weakened shifter detent mechanism so the shifter is moving a cog smaller instead of the derailleur briefing pushing the chain towards a larger cog.
Ok this seems to be the issue. From other people I talked to it sounds like the spring is wearing out (or some other part in there). Taking it into the shop.
Also, when the shift occurs I've "felt" it in my right hand, kind of like if I gripped hoods too hard it would cause a shift (fingers OFF the lever). But it happened in the drops too, so I originally ruled that out. So I'm fairly confident that it's a shifter issue now.
Thanks for the help!