Changes to inner wire tension are made at the adjusting barrel. Adjusting barrels may be located either at the rear derailleur or at the shift lever. The goal of adjusting the indexing is to find the tightest inner wire tension setting that will allow good shifting to the gears normally used. This will allow the longest lasting indexing adjustment as the system wears and the cable system stretches with use. To find the tightest inner wire setting, you will purposely make the setting too tight then relax tension slightly. There are two basic symptoms for a "too tight" inner wire. These are a rattling noise from the chain rubbing against the next cog inward, and a slow or hesitant outward shift. These are symptoms for rear derailleurs that sit outward when inner wire tension is released.
1. Set limit screws (if not already done).
2. Shift chain to outermost rear sprocket (smallest). Shift chain to outermost (largest) chainring in front.
3. Test initial inner wire tension. Pedal a normal cadence and shift rear derailleur with one click on lever. Use care to only move lever one position. If derailleur moves one sprocket, tension is adequate.
4. If derailleur fails to shift one sprocket, inner wire may be too slack. Turn barrel adjuster fully into derailleur body (or shift lever) then turn counter clockwise two turns to allow for index adjustments. Loosen inner wire pinch bolt and gently pull on inner wire with fourth hand tool or pliers to remove slack. Tighten inner wire pinch bolt.
5. If derailleur will not shift one sprocket after removing slack in "d", return lever back to outermost sprocket position and increase inner wire tension by turning barrel adjuster counter-clockwise 1/4 turn and attempt shift again.
6. Shift to second sprocket in rear. Pedal and increase inner wire tension by continuing to turn adjusting barrel counter-clockwise until a definite rattling is heard. Rattle is from chain scrapping against next sprocket.
7. Once a too-tight rattle is achieved, turn barrel adjuster 1/4 turn clockwise, to release inner wire tension, and pedal again. Listen and look for signs of scraping or rattling. Continue turning barrel adjuster 1/4 turn clockwise at a time until rattle disappears.
8. Shift derailleur one sprocket inward at a time, listening for signs of rattle, indicating a too tight inner wire. Turn adjusting barrel 1/4 turn clockwise to eliminate rattle. Note: Do not attempt shift to largest rear sprocket while in largest front sprocket. This gear is normally not used and adjusting tension to this shift may compromise other commonly used gears.
9. Shift to innermost (smallest) chainring and check gears again. If no rattling is present, index adjustment is done.