I need a new front derailleur for my Shimano Acera T3000 gear shift. I have to choose between:
They differ only in the chain stay angle they are made for. The info I find on what the "chain stay angle" is seems partly contradictory or unclear. So I want to make sure I got this:
The chain stay angle is the angle between chain stay and seat tube - is that correct?
Or more precise the angle between AB and AC with:
- A: bottom bracket axis
- B: axis of rear wheel
- C: "middle point" at the top of the seat tube
Here's my frame with measured angles:
of the angles in question only the one between seat tube and chain stay (68°) falls into the interval [63,69] ... so, it has to be that one, I suppose. From my mechanical, geometrical intuition I don't see why that angle is relevant for the FD. It should be ∠(KK',KC) in my opinion!?