Shimano FH-M640, FH-M645, FH-M648, FH-M820, FH-M825 User's Manual

(English)

User's Manual

UM-3TS0A-004

Rear Freehub (for

Downhill / Freeride)

https://si.shimano.com

Contents

IMPORTANT NOTICE........................................................................................ 3

Important safety information........................................................................ 4

Notice............................................................................................................... 5

Regular inspections before riding the bicycle .............................................. 6

Names of parts................................................................................................ 7

2

IMPORTANT NOTICE

IMPORTANT NOTICE

Contact the place of purchase or a distributor for information on installation, adjustment, and replacement of
the products which are not found in the user's manual. A dealer's manual for professional and experienced
bicycle mechanics is available on our website ( https://si.shimano.com ).

For safety, be sure to read this user's manual thoroughly before use, follow it for correct use, and store it so
that it can be referenced at any time.

The following instructions must be observed at all times in order to prevent personal injury and physical damage
to equipment and surroundings. The instructions are classified according to the degree of danger or damage
which may occur if the product is used incorrectly.

DANGER

WARNING

CAUTION

Failure to follow the instructions will result in death or serious injury.

Failure to follow the instructions could result in death or serious injury.

Failure to follow the instructions could cause personal injury or physical damage to
equipment and surroundings.

3

Important safety information

Important safety information

Do not disassemble or modify the product. This may cause the product to not operate correctly, and you
may suddenly fall and be seriously injured.

Downhill bicycle riding and freeriding are inherently dangerous activities. It is strongly recommended that
riders wear protective head and body gear and perform thorough safety checks of their bicycles before
riding. Please remember that you are riding at your own risk and that you have to consider your
experience and your skills very carefully. There is a risk of being involved in an accident that can result in
a serious injury or even death.

Check that the wheels are fastened securely before riding the bicycle. You may fall or collide and be
seriously injured.

Before riding the bicycle, you should carefully check your hubs to make sure that there are no cracks in the
axles, and if you find any unusual conditions, DO NOT use the bicycle. This free hub is designed for
downhill bicycle riding and freeriding. However, depending on the riding conditions, the hub axle could
develop cracks that result in the failure of the axle. This can lead to an accident that could result in serious
injury or even death.

When installing the rear wheel to the frame, always be sure to follow the instructions given in the manual
for the frame. The securing method and tightening torque for the rear wheel both vary depending on the
type of frame being used. Improper handling may cause the rear wheel to fall off and lead to serious
injury.

4

Notice

Notice

Do not oil the internal parts of the hub. Otherwise, the grease will flow out.

Use a neutral detergent when cleaning hubs. Other cleaners may damage the hubs. Do not clean any areas
that have been instructed not to be cleaned.

Do not clean the hub areas with a high-pressure wash. Water may get inside the hubs, which can degrade
performance.

Products are not guaranteed against natural wear and deterioration from normal use and aging.

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

5

Regular inspections before riding the bicycle

Regular inspections before riding
the bicycle

Before riding the bicycle, check the following items. If any problems are found, consult your place of purchase or
a distributor.

Are the wheels secure?

Is it hard to rotate the wheels?

Are there any abnormal noises?

6

Freehub

Hub axle

Names of parts

Names of parts

7

One Holl and, Irvine, California 92 618, U.S.A. Ph one: [phone]

High Tec h Campus 92, 5656 AG Eindho ven, The Neth erlands Phone : [phone]

3-77 Oim atsu-cho, Sak ai-ku, Sakai City, Osaka 59 0-8577, Japan

Please note: specifications are subject to change for improvement without notice. (English)
© Sep. 2024 by SHIMANO INC. ITP