Hello all. I'm hoping someone might be able to suggest where the problem with my rear shifting system lies. I've tinkered with the whole system for hours, followed setup advice in books (limit screws, indexing, B screw, etc.) and taken the bike to a mechanic, only to have the shifting fall apart a few blocks afterward.
I've replaced the following parts with brand new items:
1. Rear derailleur itself (Altus for Deore)
2. Derailleur hanger
5. Chain (length was determined using a few online calculators)
Whether it's the old Altus or the new Deore; the new or old chain, the problem is this: the cable has to be set so loose at the smallest rear cog that it almost strikes the chain in order for me to be able to shift upwards at all. By the time I'm close to the larger rear cogs it is almost impossible to push the shifting lever (and I wouldn't try). The cable by this time has become way too tight.
If I try to readjust and loosen the cable a tiny bit, then shifting around the smaller cogs is completely useless - the rear derailleur doesn't move at all because the cable is so loose.