Originally Posted by Retro Grouch
I'm thinking that, once you get everything else right, 100% of shifting problems can be attributed to cable tension.
In your case I'm pretty sure that a 1/4 turn adjustment on your low limit screw will keep your bike from auto-shifting. Your derailleur hanger may be tweaked a bit too.
Uh-uh. I lowered the cable tension, and presto! It is perfect now. The problem was that the cable tension was simply too high in the first gear, and this caused the shifter to snap itself into second gear. Giving it a tad bit of slack kept the shifting crisp, but avoided tensioning the cable so much in first gear.
It's like there was so much tension, I was BARELY able to get into first, but the shifter would not hold it there.
The low limit screw may be an issue, but I was having trouble with the der. rubbing the spokes, so I think it's set up properly now. And the deralleur hanger tweaked? I doubt it. I did ahve a crash, but that was on the other side of the bike. Plus, on my frame, it is integrated into the frame, and the hanger is 7mm thick titanium. The der. bolt would snap before bending the hanger.