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Chapter 3: Inspection and adjustment
Derailleurs
A derailleur shifts gears by pushing the chain
from one cog or chainring to the next. These
instructions are written for standard, cable
operated derailleurs. For electronic systems,
visit the manufacturer’s website.
Front derailleur
With bicycles that have more than one
chainring, the front derailleur moves the chain to
change gears.
Each month, or after any adjustment, check the
front derailleur. Change gears to all the gear
combinations and check these items:
• The chain should not come off .
• The chain should line up smoothly with each
chainring and not rub the chain.
•The derailleur cage should not rub
the crankarm.
To adjust the small chainring position
1. Move the chain to the smallest front chainring
and the largest rear cog.
2. Loosen the cable clamp bolt (Figure 3.10)
until the cable is free.
3. Turn the low gear limit screw (identified with an
“L”) until the inner chain guide of the derailleur
is approximately 0.5 mm from the chain.
4. If there is a barrel adjuster on the shift lever
or the down tube of the frame, turn the barrel
adjuster fully clockwise.
5. Pull on the cable end, and move the left shift
lever to the small chainring position.
6. Put the cable in the groove found near the
cable clamp bolt. Pull the cable tight and
tighten the clamp bolt to 35-53 lb•in
(4-6 Nm).
To adjust the large chainring position
1. Move the rear derailleur to the smallest rear
cog.
2. Turn the high-gear limit-screw (identified with
an “H”) counterclockwise until it can not stop
the movement of the derailleur.
3. Turn the crankarms with your hand. Use the
shift lever to carefully move the chain to the
outside chainring.
4. Move the outer chain-guide so that it is
approximately 0.5 mm from the chain.
5. Tighten the high-gear limit-screw until it
resists. If you have turned the screw too far,
the front derailleur will rub on the chain or
move the chain to a smaller chainring.
To adjust the middle-gear position
(with three chainrings)
1. Move the chain to the largest front chainring
and the smallest rear cog.
2. Turn the cable barrel-adjuster (on the down
tube, the cable housing, or on the lever) to
change the cable tension and align the inner
cage of the derailleur until it touches the
chain.
Rear derailleur
On bicycles with more than one cog on the rear
wheel, the rear derailleur moves the chain to
change gears.
Each month, or after any adjustment, check
the rear derailleur. Change gears to all the gear
combinations to make sure the chain smoothly
lines up with each of the rear cogs. Make sure the
chain does not come off when you change gears.
To adjust the small-cog position
1. Move the chain to the smallest rear cog and
the largest front chainring.
2. Loosen the cable-clamp bolt (Figure 3.11) until
the cable is free.
FIGURE 3.11
Rear derailleur
1. Limit-screws
2. Barrel-adjuster
3. Cable-clamp bolt
4. Cable
1
4
2
3
FIGURE 3.10
Front derailleur
1. Cable
2. Limit-screws
3. Cable-clamp bolt
1
2
3
