Servicing the Derailleur Pulleys
Derailleur pulleys should be kept free of crud. Sometimes, a problem with the
rear derailleur will be due to a bit of grass and mud wrapped around the base of
a pulley. Clean the pulleys thoroughly, carefully checking the area between the
cage and the pulley. A degreasing solution helps.
Derailleur pulleys can be damaged if the rear shifting is out of adjustment
(the chain sits slightly off center, scraping the pulley), or due to mud- and
sand-riding. Or, the bearings may freeze up from crud, rust, or wear.
||Inspect the pulleys. If they don't spin freely, or if the
teeth are gouged or worn down, replace them. Use pulleys specific to your
derailleur: the top pulley for a grip shift (or friction shift) system
usually has no side-to-side play, while an index-shifter (rapid-fire) may
have 1/8-inch of side to side motion.
||Note the position of the chain relative to the pulley you're
replacing -- it's easy to get "lost." If the bike is upside-down
with the wheel off, the top side of the chain goes around the most distant
pulley, then over-top of the pulley closer to the frame.
Remove the pulley by unscrewing the hex-head bolt.
||Slide the new pulley into position.
||Apply a thread-locking compound ("Loctite") to the
Now insert the bolt and tighten it into place.
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