Shimano SG-8C20, CJ-8S20 Technical Service Instruction

General Safety Information

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WARNING

It is important to completely understand the
operation of your bicycle's brake system.
Improper use of your bicycle's brake system may
result in a loss of control or an accident, which
could lead to sever injury. Because each bicycle
may handle differently, be sure to learn the
proper braking technique (including bicycle
control characteristics) and operation of your
bicycle. This can be done by consulting your
professional bicycle dealer and the bicycle
owner's manual, and by practicing your riding and
braking technique.

When securing the brake arm to the frame, be
sure to use a brake arm clip that matches the
size of the chainstay, and securely tighten them
with the clip screw and clip nut to the specified
tightening torque.
Use a lock nut with a nylon insert (self-locking
nut) for the clip nut. It is recommended that
standard Shimano parts be used for the clip
screw, clip nut and brake arm clip. In addition,
use a brake arm clip that matches the size of the
chainstay.
If the clip nut comes off the brake arm, or if the
clip screw or brake arm clip becomes damaged,
the brake arm may rotate on the chainstay and
cause the handlebars to jerk suddenly, or the
bicycle wheel may lock and the bicycle may fall
over, causing serious injury.

When installing the hub to the frame, be sure to
install the correct non-turn washers to the left and
right sides, and securely tighten the hub nuts to
the specified torques. If the non-turn washers are
installed to one side only, or if the hub nuts are
not tightened sufficiently, the non-turn washer
may fall out, which could cause the hub axle to
rotate and the cassette joint to turn. This may
then cause the handlebars to be accidentally
pulled by the shifting cable, and an extremely
serious accident could result.

Obtain and read the service instructions carefully
prior to installing the parts. Loose, worn, or
damaged parts may cause serious injury to the
rider.
We strongly recommend only using genuine
Shimano replacement parts.

Check that the wheels are fastened securely
before riding the bicycle. If the wheels are loose
in any way, they may come off the bicycle and
serious injury may result.

Read these Technical Service Instructions
carefully, and keep them in a safe place for later
reference.

– To avoid serious
injuries:

CAUTION

Avoid continuous application of the brakes when
riding down long slopes, as this will cause the
internal brake parts to become very hot, and this
may weaken braking performance. It may also
cause a reduction in the amount of brake grease
inside the brake, and this can lead to problems
such as abnormally sudden braking.

Spin the wheel and confirm that the braking force
of the coaster brake is correct.

If the brakes are used frequently, the brake drum
may become hot. Do not touch the brake drum
for at least 30 minutes after you finish riding the
bicycle.

Brake drum

– To avoid serious
injuries:

NOTE:

You can shift gears while pedaling, but on rare
occasions the pawls and ratchet inside the hub
may produce some noise afterwards as part of
normal gear shifting operation.

The CJ-8S20 cassette joint should only be used
with sprockets from 16T to 23T.

If the wheel becomes stiff and difficult to turn, you
should replace the brake shoes or lubricate with
grease.

Do not apply any lubricant to the inside of the hub,
otherwise the grease will come out.

You should periodically wash the sprockets in a
neutral detergent and then lubricate them again.
In addition, cleaning the chain with neutral
detergent and lubricating it can be a effective way
of extending the useful life of the sprockets and
the chain.

If the chain keeps coming off the sprockets during
use, replace the sprockets and the chain.

Parts are not guaranteed against natural wear or
deterioration resulting from normal use.

For maximum performance we highly recommend
Shimano lubricants and maintenance products.

For any questions regarding methods of handling
or adjustment, please contact the place of
purchase.

SI-35P0A

Inter-8 Hub

SG-8C20
CJ-8S20

with Coaster Brake

Cassette Joint

Technical Service Instructions

Turn the cassette joint pulley in the direction of the

2.

arrow in the illustration to align the red marks on the
pulley and the bracket. With the cassette joint in this
condition, install it so that the red mark on the
cassette joint is aligned with the red mark on the right
side of the hub body.

Should be aligned

Pulley

Bracket

CJ-8S20

JAPAN

Cassette joint

Be sure to read these service instructions in
conjunction with the service instructions for the
Inter-8 shifting lever before use.

Installation of the cassette joint to
the hub

Install the driver cap to the driver on the right side of the

1.

hub body.

Driver cap

Driver

Driver cap

Note the
direction

CJ-8S20

JAPAN

Align the red
marks to install.

Align the red
marks to install.

Right side of
the hub body

1)

Secure the cassette joint to the hub with the cassette

3.

joint fixing ring. When installing the cassette joint
fixing ring, align the yellow mark with the yellow
mark on the cassette joint pulley.

Cassette joint fixing ring

LOCK

Align the
yellow marks
to install.

Cassette joint pulley

CJ-8S20

JAPAN

2)

After installing the cassette joint fixing ring, turn it 45
clockwise.

Turn 45

LOCK

CJ-8S20

JAPAN

Cassette joint fixing ring

Fit the cassette joint
bracket securely.