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SI-5X20A-005-00
General Safety Information
WARNING
"Maintenance interval depends on the usage and riding circumstances. Clean regularly the
chain with an appropriate chaincleaner. Never use alkali based or acid based solvents such as
rust cleaners. If those solvent be used chain might break and cause serious injury."
• In order to obtain good gear shifting performance, the CN-7901 has a forward side and a reverse side,
and the sides are marked so that the CN-7901 will face the correct way when installed. The proper design
performance will be obtained when the CN-7901 is installed so that it faces the correct way. If it is
installed so that it faces the opposite way, the chain may come off and the bicycle may fall over and
serious injury may occur as a result.
• Use the reinforced connecting pin only for connecting the narrow type of chain.
• If connecting pins other than reinforced
Reinforced
Chain
connecting pins are used, or if a reinforced
connecting pin
connecting pin or tool which is not
with
suitable for the type of chain is used,
10-speed
groove (3)
sufficient connection force may not be
super narrow chain
obtained, which could cause the chain to
such as CN-7901
with
groove (2)
break or fall off.
• Make sure that the connecting pin is aligned with the outer
link surface from the side that the pin is inserted. It should
feel smooth and flush when you run your finger over it. The
pin will protrude slightly on the backside after the break
off pin is removed.
• If it is necessary to adjust the length of the chain due to a
Reinforced Connecting Pin
change in the number of sprocket teeth, make the cut at
some other place than the place where the chain has been
joined using a reinforced connecting pin. The chain will be
damaged if it is cut at a place where it has been joined with
a reinforced connecting pin.
Link Pin
• Check that the tension of the chain is correct and that the
chain is not damaged. If the tension is too weak or the chain is damaged, the chain should be replaced. If
this is not done, the chain may break and cause serious injury.
• Obtain and read the service instructions carefully prior to installing the parts. Loose, worn or damaged
parts may cause the bicycle to fall over and serious injury may occur as a result. We strongly recommend
only using genuine Shimano replacement parts.
• Obtain and read the service instructions carefully prior to installing the parts. If adjustments are not
carried out correctly, the chain may come off and this may cause you to fall off the bicycle which could
result in serious injury.
• Read these Technical Service Instructions carefully, and keep them in a safe place for later reference.
Note
<RD-7970 / RD-7970-A>
• Be sure to adjust the top adjustment bolt and the low adjustment bolt by following the procedures in
the Service Instructions. If these bolts are not adjusted, the chain may become clamped between the
spokes and the largest sprocket and the wheel may lock, or the chain may slip onto the smallest sprocket.
• If the amount of looseness in the links is so great that adjustment is not possible, you should replace the derailleur.
• Periodically clean the derailleur and lubricate all moving parts and pulleys.
• If gear shifting adjustment cannot be carried out, check the degree of parallelism at the rear end of the bicycle.
• If you hear abnormal noise as a result of looseness in a pulley, you should replace the pulley.
• The tension pulley has a mark which indicates the direction of rotation. The side with the arrow is the front side.
• Be sure to use the following tools when removing cables.
RD-7970:TL-EW01
RD-7970-A:TL-EW02
• Be careful not to let water get into the terminal.
• For any questions regarding methods of installation, adjustment, maintenance or operation, please
contact a professional bicycle dealer.
• 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.
<SM-RD79-A>
Be sure to also inform users of the following:
• This is a small waterproof connector. Do not repeat connecting and disconnecting it. It may impair the function.
• Be careful not to let water get into the terminal.
• The components are designed to be fully waterproofed to withstand wet weather riding conditions;
however, do not deliberately place them into water.
• Do not clean the bicycle in a high-pressure wash. If water gets into any of the components, operating
problems or rusting may result.
• Handle the products carefully, and avoid subjecting them to any strong shocks.
• Do not use thinners or similar substances to clean the products. Such substances may damage the surfaces.
• Do not leave the product in an area exposed to strong sunlight for an extended period of time.
• Do not disassemble the product as it cannot be reassembled.
• When cleaning the product, use a cloth moistened with a diluted neutral detergent.
• Be sure to use the Shimano original tools TL-EW01 and TL-EW02 when removing electric wires.
• Be sure to use the specified electric wire.
• Secure the electric wires with plastic tape so that they do not interfere with the chainrings, sprockets and tires.
• Before riding check that the rubber band is not cracked or damaged. If the rubber band is cracked or
damaged use a new one.
• If the double-sided tape on SM-RD79-A peels off, replace it with a new one.
• 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.
Notes when reinstalling and replacing components
• When installing to the bicycle, do not forcibly bend the electric wire plug. It may result in a poor contact.
The actual product may differ from the illustration because this manual is intended chiefly to explain
the procedures for using the product.
Please note: specifications are subject to change for improvement without notice. (English) © Apr. 2016 by Shimano Inc. HTR
Technical Service Instructions
RD-7970 / RD-7970-A / SM-RD79-A
Rear derailleur
In order to realize the best performance, we recommend that the following
combination be used.
Series
DURA-ACE
Dual control lever
ST-7970
Gears
10
Electric cable
EW-7970 / SM-EW79A
Chain tool
Battery
SM-BTR1
RD-7970
Rear derailleur
TL-CN32
RD-7970-A / SM-RD79-A
TL-CN23
SS
Type
TL-CN27
FH-7900
Freehub
CS-7900 (Except for 11-28T)
Cassette sprocket
CN-7901
Chain
Specifications
SS
Type
32 teeth or less
Refer to the Service Instructions for
Total capacity
27 T
the electric cable when connecting
Largest sprocket
11 T
and routing the electric cable.
Smallest sprocket
Link Pin
16 teeth or less
Front chainwheel tooth difference
Installation of the rear derailleur
When installing the rear derailleur, make sure that the B-tension adjustment bolt does not touch the fork of
the dropout and cause it to bend.
Fork of dropout
B-tension adjustment bolt
Pulley cage
* Guide pulley / tension pulley tightening
torque:
2.5 - 3 N·m
Chain length
Note:
In order to obtain good gear shifting performance, the CN-7901
has a forward side and a reverse side, and the sides are marked
Guide
so that the CN-7901 will face the correct way when installed.
pulley
Forward
(outer side)
Tension
The side with the mark shown in the illustration is the
pulley
forward side (outer side).
Right angle to the ground
Reverse
(inner side)
About RD Protection
* Rotate the front chainwheel when activating RD Protection Reset.
If the bicycle receives a strong impact, the RD Protection operates and the connection between the motor
and the link is momentarily severed so that the rear derailleur will no longer operate. If this happens, hold
down the rear derailleur adjustment button on junction (A) of SM-EW79A for 5 seconds or longer to activate
RD Protection Reset, which will restore the connection between the motor and the link. If RD Protection
Reset does not activate, manual recovery is also possible. Consult with a distributor in advance.
Junction (A)
Rear derailleur
adjustment button
Button held
Illuminates (red)
Flashes (red)
down
Approx. 5-second period
When the red LED on junction (A) is illuminated, the rear derailleur cannot shift gears. Press the rear
derailleur adjustment button until the red LED turns off.
Installation of RD-7970-A / SM-RD79-A
SI-5X20A-005
LIST OF TOOLS TO BE USED:
• Tool used when connecting/removing the electric wire to/from RD-7970: TL-EW01
• Tool used when connecting/removing the provided 200mm electric wire: TL-EW02
Attach SM-RD79-A to the seat stay of the bicycle frame.
* Not compatible with seat stays with a cross-sectional width greatly exceeding the width of SM-RD79-A.
SM-RD79-A
EW-7970
EW-SD50
RD-7970-A
Note: Use SM-RD79-A in combination with RD-7970-A.
Use the provided 200mm electric wire (EW-SD50) to connect SM-RD79-A and RD-7970-A.
RD-7970-A / SM-RD79-A are not compatible with E-TUBE PROJECT.
1. Shift to the largest front chainring and to the smallest rear sprocket.
Wipe the dirt and dust off the frame, and if the frame is wet, dry it well before attaching.
5 mm Allen key
2. There are two types of rubber sheet.
Choose the rubber sheet that fits the frame.
Peel the rubber sheet from its release liner and attach
it to SM-RD79-A.
Be careful about the orientation of the rubber sheet.
Attach it with its wider side facing the connector.
After attaching the rubber sheet, hold down the
entire surface with your finger for approximately 1
minute.
Bracket tightening torque:
8 - 10 N·m
3. Provisionally attach SM-RD79-A to the frame using
the rubber band.
Connect the rubber band to one of the hooks, pull it
around and then attach it to the other hook.
Smallest
Largest
sprocket
chainring
Chain
90°
4. Remove the electric wire from RD-7970 using the
Shimano original tool TL-EW01.
Remove RD-7970 and attach RD-7970-A.
Illuminates (red)
RD protection
Complete
reset
5. Pass the electric wire through the provided Shimano
original tool TL-EW02.
Set so that the projection on the connector is aligned
with the groove on the narrow end.
TL-EW02
Plug
* When installing the electric wire, do not forcibly bend the plug. It may result in a poor contact.
When connecting the electric wire, push it in until it clicks in place.
SM-RD79-A
6. Connect the following 2 electric wires to SM-RD79-A:
• Electric wire disconnected from RD-7970
• Provided 200mm electric wire (EW-SD50)
* Hold the wireless unit in your hand when
connecting or disconnecting the electric wire from
SM-RD79-A.
SM-RD79-A
7. Connect the electric wire to RD-7970-A.
8. Check the excess length of the electric wire. (Push up the rear derailleur until it makes contact with the
Rubber Sheet
frame and keep it in that position when checking the electric wires.) If the electric wire does not have
(Y7G998010)
enough slack, make some fine adjustments to the height of SM-RD79-A.
Hook
Frame
9. Secure SM-RD79-A to the frame.
Rubber Band
(Y7G900050)
10. Secure the electric wire to the frame.
* If the electric wire is too long, it may interfere with
the cassette sprocket or chain. Use plastic tape, etc.
to secure the slack electric wire to the frame.
* Refer to the Service instructions for the ST-7970 for details on stroke adjustment.
When inserting the electric
wire removed from RD-7970,
align the marks on
SM-RD79-A and the plug.
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