Detailed Maintenance
Detailed Maintenance
Lubrication
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Derailleur Systems
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Lubrication
Remove any accumulated dirt from the freewheel with a brush and a
degreaser. Disassembly of the freewheel is a complicated procedure
requiring special tools, and should be left to a specialist. Apply oil to the
freewheel whenever you lubricate that chain, taking care to wipe off any
excess.
COASTER HUB
Many BMX style and other children’s bicycles are fitted with a coaster
hub brake in the rear wheel. This type of brake offers the advantages
of reliability and easy operation. The brake is operated by applying back
pedal pressure and allows the rider the ‘coast’ without pedaling, if desired.
There are several models of coaster hubs available, and the internal
mechanisms are very complex. They require infrequent attention as far
as lubrication, adjustment or replacement of internal parts; if needed, this
should be left to a specialist.
Keep the coaster hub sprocket clean and oil it along with the chain.
Make sure the brake arm is correctly attached to the
chainstay with the brake arm clip. The brake will not
operate otherwise.
Brake Arm Clip
Brake Arm
Sprocket
DERAILLEUR SYSTEMS
The derailleur system includes the front and rear derailleurs, the shift levers, and the derailleur control cables, all of which must function
correctly for smooth gear shifting to occur. There are several different types of derailleur systems but all operate using similar principles.
Your new bicycle may be fitted with a standard ‘friction’ type system where you will need to feel each gear shift into position. It may be
fitted with an ‘index’ system (e.g. SIS) which links each different gear position to a positive click mechanism in the shifter, and makes
shifter, and makes shifting very simple and precise. A further development of SIS is the fully integrated system (e.g. STI) where the shift
lever and brake lever mechanisms from an integrated unit with the system allowing both gear shifting and braking to occur at the same
time.
Inspection
The operation of the derailleur system should be checked at least every
month. Check the operation of the rear derailleur first, then the front. The
rear derailleur should shift the chain cleanly form on cog to the next without
hesitation. On SIS equipped bicycles, each notched position in the shifter
must equate to a new gear position. After shifting, the rear derailleur should
not rub on the chain. The derailleur should never cause the chain to fall off
the inner or outer freewheel cogs.
The front derailleur should also shift the chain cleanly and equipped with
front SIS, then each click or stop in the shifter should equate exactly to
a new gear position. When the chain has been positioned onto a new
chainring, it should not rub on the front derailleur. The chain should not fall
off a chainring at any time. Derailleur control cables are a critical component
that must be well maintained for accurate shifting performance.
Check them for any sign of rust, fraying, kinks, broken strands, and any
damage to the cable housing. If you find any problems, the cables may need
replacing before you ride.
Pre-stretch the derailleur
cables to remove slack
Stretch
Summary of Contents for BMX BICYCLES
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