Is my indexed shifter compatible with my long cage derailleur?
Here's the situation: I have a folding bike that I'm cannibalizing for parts. It had an indexed shifter (six speed) and a short cage shimano derailleur. I put the indexed shifter on an 18 speed mountain bike that has a long cage derailleur.
The rear cassette on the mountain bike also has a bigger range than the cassette on the folding bike did.
I have it tuned now so it is working somewhat reasonably but not quite perfect. It lines up perfectly for gear 6, but as I move up it skips a gear somewhere so that when the shifter is at 2, the chain is all the way on one.
What I'm wondering is whether it's just a matter of more adjustment, or if this shifter only works properly with a short cage derailleur. If that's the case I can swap out the derailleur but then will I need to shorten the chain?