Replacing the Rear Derailleur |
You're riding along, sprinting up the trail, when you suck a stick into the
rear derailleur. POW! Your derailleur is toast. Believe it or not, it's
not difficult to replace the rear derailleur yourself. Before replacing a
"bent derailleur" make sure it's not just the derailleur
hanger!
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First, remove the idler pulley --
that's the bottom pulley of the derailleur. This pulley holds the chain
inside the derailleur mechanism. Without it, the derailleur can slide
backwards away from the chain.
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Unscrew the derailleur from the derailleur hanger by
inserting a hex wrench and turning counter-clockwise.
The derailleur will now come away from the hanger. |
Remove the derailleur cable by loosening the hex bolt on the
cable retaining clamp. Take the end cap off the cable, and draw the cable
through the derailleur.
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Put the new derailleur into position, holding it up and back
(clockwise) from its usual position, so the tension adjusting screw is
above the notch on the hanger.
Thread the mounting bolt into the hanger. |
Route the chain through the derailleur. If you took the
idler pulley off, put it above the chain, then bring the chain down and
back into the cage of the derailleur. Now attach the idler pulley.
If you split the chain, route it by hand. It goes forward ABOVE the top
pulley, down in FRONT of the pulley, around the BACK of the lower pulley,
then forward BELOW the bottom pulley. Fix the
chain. |

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Back off any cable-tension adjusters (usually found where
the cable enters the derailleur and sometimes at the shifter) so you've
got room to adjust the tightness of the cable when it's time to tune up
the shifting.
Push the derailleur cable through the receptacle on the back
of the derailleur. Pull the cable hard to remove any obvious slack. Then
relax your pull on the cable and thread it through the cable clamp. Screw
in the cable clamp bolt to tighten it down onto the cable. |
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