Figure 1:
Cable clamp bolt for rear derailleur
Chapter 3: inspection, adjustment, and lubrication
Derailleur adjustment should be done with the bicycle held firmly in a workstand, or with someone holding the rear wheel off the ground such that the drivetrain and shift system can be operated while the bicycle remains stationary.
1. Shift the chain onto the smallest rear cog and the largest front chainring.
2. Loosen the cable clamp bolt (Figure 1) until the cable is free.
3. Stand behind the bicycle to see that the smallest rear cog, the chain, and the two derailleur pulleys are in line.
4. If they are not aligned, turn the high gear adjusting screw (usually marked “H”, Figure 2) until this line is established.
5. While pulling on the cable, up-shift until the shifter is in the small cog position.
6. Turn the adjusting barrel on the shifter, or down tube, all the way clockwise. Turn the adjusting barrel on the rear derailleur all the way clockwise, and then one turn counter-clockwise.
7. Insert the cable into the clamp bolt groove on the rear derailleur, pull the shift cable taut, and clamp the cable to the torque specifications.
|
|
Figure 1: Cable clamp bolt for rear derailleur |
|
|
Figure 2: Inner limiting screw affects low gear |
1. Turn the low gear adjusting screw on the rear derailleur (usually marked “L”, Figure 3) far enough counter-clockwise so that it will not restrict the movement of the derailleur.
2. Carefully shift the chain onto the smallest front chainring and the largest rear cog.
Do not over-shift the rear derailleur, or the chain may wedge between the large cog and the spokes.
3. Position the rear derailleur pulleys in line with the largest cog.
4. Turn the low gear adjusting screw clockwise until it meets resistance.
If you have turned it too far, the derailleur will move toward the outside of the bicycle.
5. Go through the various gear combinations to make sure the chain does not fall off when you shift.
|
|
Figure 3: Outer limiting screw affects high gear |
1. Shift the chain onto the largest front chainring and the smallest rear cog.
2. Shift one click with the rear shifter.
3. Check if the chain moves smoothly to the next gear.
4. If the chain makes excessive noise or does not shift, turn the barrel-adjuster counter-clockwise in small increments and check again for a smooth shift.
If instead, the chain moves to the third smallest cog, turn the barrel adjuster clockwise until alignment with the derailleur pulleys and the second smallest cog is achieved.
5. Go through the various gear combinations to ensure the chain smoothly lines up with all the rear cogs.
If the derailleur cannot be adjusted in this manner, the derailleur hanger may be out of alignment; take the bicycle to your Trek dealer for service.
