Please help me (re-)adjust my .Shimano 105 9x rear derailleur of my ancient Shimano 105 3x9 gruppo. It's a RD-5501, as my research seems to support.
The prequel: After working fine for many kilometers, the pulley cable came loose. I re-installed the cable, of course.
But ever since, the rear derailleur seems to shift randomly into a neighbouring gear without me moving the shift levers. It seems to happen mostly when the chain is on the "middle" cogs; when I shift into the largest or smallest gear, the chain stays on its cog just fine.
The last procedure I tried was as follows:
- Loosen cable
- Chain on greatest sprocket in front, smallest cog in the rear; 2.1. turn the crank and loosen "high" screw until the chain starts rattling 2.2. tighten the "high" screw until the rattling stops
- Turn cable tensioner to most-"loose" position
- Install pulley cable
- Chain on middle (!) sprocket in front, largest cog in the rear; 5.1. tighten "low" screw until rattling starts 5.2. loosen "low" screw until rattling stops
- Try out all other cogs - all gears seem to shift nicely.
Still, when I ride only a short distance, once the chain is on a middle-ish cog, 4th to 6th, it jumps to the next cog intermittantly.
What am I doing wrong?