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• If routing the casing upward:

(The chain should be on the largest chainring and on the
largest sprocket.)
Add 10 mm to the length of the outer casing from the end
that is inserted into the outer casing holder to the end
which is inserted into the link.

• If routing the casing downward:

(The chain should be on the largest chainring and on the largest sprocket.)
Set the length of the outer casing so that it describes a smooth arc, and so that the
link stops in a position where there is a small gap between the link and the link stop.

Rear derailleur

Adjustment Method 

RD-TX70 / RD-TX50 / RD-TX30

Technical Service Instructions

SI-5V80A

Loosen the outer casing adjustment
barrel until the chain touches the 3rd
sprocket and makes noise. (counter
clockwise)

Tighten the outer cable adjusting barrel
until the chain returns to the 2nd
sprocket. (clockwise)

Best setting

The best setting is when the shifting lever is operated just enough to
take up the play and the chain touches the 3rd sprocket and makes
noise.
* Return the lever to its original position (the position where the lever

is at the 2nd sprocket setting and it has been released) and then turn
the crank arm clockwise. If the chain is touching the 3rd sprocket
and making noise, turn the outer casing adjustment barrel clockwise
slightly to tighten it until the noise stops and the chain runs smoothly.

Mount the chain on the smallest chainring
and the largest sprocket, and turn the crank
arm backward.  Then turn the B-tension
adjustment screw to adjust the guide pulley
as close to the sprocket as possible but not
so close that it touches.  Next, set the chain
to the smallest sprocket and repeat the
above to make sure that the pulley does not
touch the sprocket.

1

2

1

2

2

1

Operate the shifting lever several times to move the chain to the
2nd sprocket. Then, while pressing the lever just enough to take
up the play in the lever, turn the crank arm.

SIS Adjustment

B-tension 

ajustment screw

Largest sprocket

Smallest sprocket

1

2

1

2

Guide pulley

Largest
sprocket

Pull

Groove

Note: Be sure that the cable is

securely in the groove.

Tightening torque: 

5 - 7 N·m {44 - 60 in. lbs.}

2. Connection and securing of cable

Connect the cable to the rear derailleur and, after taking up the initial slack in the
cable, reattach to the rear derailleur as shown in the illustration.
Secure the cable by pulling it with pliers with a force of 5 - 10 kg.

3. Low adjustment

Turn the low adjustment screw so that the
guide pulley moves to a position directly
below the 

largest sprocket.

4. How to use the B-tension adjustment screw

For the best SIS performance, periodically lubricate all power-transmission parts.

When shifting to 3rd

Play

When no sound at all is
heard

Chain length

Add 2 links (with the chain on both the largest
sprocket and the largest chainring)

Chain

Large

chainring

Largest

sprocket

Cable securing and stroke adjustment

Installation of the rear derailleur

Push in and

tighten

Tightening torque:

8 - 10 N·m {70 - 86 in. lbs.}

5 mm Allen Key

Place the outer casing so that it does not touch the basket and mudguard, otherwise it
may cause a problem with the performance of the derailleur.

Set the outer casing (RD-TX70/RD-TX50) so that its length is as follows.

Outer casing holder

Link

Largest

sprocket

Largest

chainring 

Link stop

Link

Chain position

Largest

sprocket

Largest

chainring 

Chain position

L

Connect the inner cable to the derailleur as shown in the
illustration.

Inner cable

1. Top adjustment

Turn the top adjustment screw to adjust so
that the guide pulley is below the outer line
of the smallest sprocket when looking from
the rear.

max. 
angle

max. 
angle

®

One Holland, Irvine, California 92618, U.S.A.  Phone: +1-949-951-5003

Industrieweg 24, 8071 CT Nunspeet, The Netherlands  Phone: +31-341-272222

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

Please note: specifications are subject to change for improvement without notice. (English)  
© Apr. 2003 by Shimano Inc.  XBC SZK Printed in Singapore

This service instruction explains 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.

1

2

1

2

Guide pulley

Outer line of smallest 
sprocket

Top 
adjustment 
screw

Low adjustment
screw

adjustment
barrel

RD-TX70
RD-TX50

RD-TX30

adjustment
barrel

RD-TX70
RD-TX50

RD-TX30

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