Shimano DH-3N20, DH-3N30 Service Instructions

General Safety Information

WARNING

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.

Check that the lamp illuminates normally when riding at nighttime.

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

CAUTION

The hub dynamo generates an extremely high voltage. Never touch the connection
terminal of the hub dynamo directly while riding the bicycle or while the wheel is
spinning. Touching the dynamo terminal may cause an electric shock.

NOTE:

According to German regulations (StVZO), a hub dynamo in Germany requires
overvoltage protection. This hub dynamo does not have overvoltage protection inside
the hub itself. Use an external overvoltage protector with a symbol to show that it
complies with the German regulations (Shimano SM-DH10 overvoltage protector or
similar product).

Check the degree of parallel of the front fork end. If the front fork end is severely out of
parallel, deformation of the hub axle may cause noise from an obstruction inside the
hub dynamo to be generated.

Install the hub dynamo to the front fork so that the side with the connection terminal is
on the right when facing toward the front of the bicycle. If the side with the connection
terminal is facing toward the left, the hub dynamo may not turn properly while riding.

Check that the hub dynamo connection terminal is securely connected before using the
hub dynamo.

Use a 6 V/ 2.4 W bulb for the front lamp and a 6 V/ 0.6 W bulb for the taillamp.

If the bulb of either the front lamp or taillamp blows, excessive voltage will be applied to
the remaining lamp and shorten the operating life of the bulb, so any blown bulbs
should be replaced as soon as possible.

If the lamp is frequently turned on when riding at high speed ranges, it will shorten the
operating life of the bulbs.

Do not disassemble the internal hub mechanism.

Do not apply any lubricant to the inside of the hub, otherwise the grease will come out
and it may cause problems with conductivity.

The hub dynamo will cause the turning of the wheel to become slightly heavier
because of the magnet inside the hub.

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

DH-3N30

– To avoid serious injuries:

Hub Dynamo

DH-3N20

Technical Service Instructions

SI-25V0G

Connection of the cables

Connect the cables as shown in the illustration below.

Frame connection
terminal

Lamp connection
terminal

Lamp cable

Approx. 16 mm

Connector cap (gray)

Connector cover (black)

Note:

Set so that it faces the
right way.

Press in until you hear
a click.

Lamp connection terminal

Note:

Secure the cable to the front fork or the basket stay so that it will not
get caught in the spokes or any other parts while riding. If the
position of the hub dynamo may change with respect to the lamp
while riding, for example when using a suspension fork, make sure
that the cable is connected so that it will not be too loose or too tight
at any point within the range of movement.

Connect so that the current from the hub dynamo flows through the
cable from the lamp connection terminal of the hub dynamo to the
frame connection terminal.

To disconnect the lamp from the hub dynamo, remove the connector
cover.

Do not ride the bicycle while the connector cover is removed, otherwise the cable might
get caught in the bicycle wheel.

When removing the bicycle wheel, first remove the connector cover. If the cables are
pulled strongly, it may break the cable wires or cause poor contacts. Furthermore, when
installing the wheel, first secure the wheel to the front forks and then connect the
connector cover.

Note:

Do not switch over the frame cable and the lamp cable
by mistake. If the cables are connected incorrectly, the
lamp will not illuminate.

Twist the cable wires before connecting them so that
they stay together.

Recommended wire specifications

Type

Wire

Insulation

Approx.
16 mm

Wire

Stranded
Size (AWG) 22

Diameter approx. 0.8 mm
Diameter 1.8 – 2 mm

Frame cable

Note:

Bend the cable wires and run them
along the grooves.

Insulation

Insert

Groove

Do not allow the cable wires to
touch each other.

Hub dynamo connection terminal

Frame connection terminal

Bend

Remove

Connector
cover

Installation of the front wheel

Install the wheel so that the side with the hub dynamo connection terminal is on the
right side when looking toward the front of the bicycle, and so that the hub
connection terminal is aligned with the front fork or with the basket stay. Then
install by following the procedure shown in the illustration below so that the
connection terminal is facing upward. Do not force the connection terminal to turn
after the quick release nut or the cap nut has been secured.

For quick release type

Front fork

Connection
terminal

Mudguard stay

Quick release nut

Note:

Do not use the toothed axle washer with a quick release type.

Connect the two wires to ensure that the current flows smoothly.

For nut type

Basket stay

Front fork

Connection
terminal

Mudguard stay

Quick release nut

Mudguard stay

Connection terminal

Front fork

Volute spring

Connection terminal

Front fork

Connector cover

Connect

Checking the lamp illumination

Rotate the front wheel and check that the lamp illuminates.

Cable

Front fork

Mudguard stay

Tightening torque:
20 N·m {174 in. lbs.}

Cap nut (M9)

Note:

When tightening the cap nuts, tighten the
nuts alternately on both sides and do not
concentrate all of the effort for tightening
and loosening the cap nut on one side of
the wheel only, otherwise the hub axle
may turn, which could excessively tighten
or loosen the lock nuts.

Toothed axle washer

Basket stay

Washer

Note:

If the cable connected to the ground
terminal is not properly grounded,
check that the toothed axle washer
perforates the paint surface of the front
fork. If the toothed axle washer is not
perforating the paint surface, the lamp
will not illuminate properly, so scrape
away a small amount of paint from the
front fork.

It is recommended that you connect the
two wires to ensure that the current
flows smoothly.

These service instructions explain how to use and maintain the Shimano bicycle parts which have been
used on your new bicycle. For any questions regarding your bicycle or other matters which are not
related to Shimano parts‚ please contact the place of purchase or the bicycle manufacturer.

Please note: Specifications are subject to change for improvement without notice. (English)

One Holland, Irvine, California 92618, U.S.A. Phone: [phone]

Industrieweg 24, 8071 CT Nunspeet, The Netherlands Phone: [phone]

3-77 Oimatsu-cho, Sakai-ku, Sakai, Osaka 590-8577, Japan

C

Jul. 2006 by Shimano Inc. PIT. SZK. Printed in Singapore