Shimano Nexus SG-8C20 Service Manual
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Shimano Nexus SG-8C20 Service Manual

Shimano Nexus SG-8C20 Service Manual

Inter-8 coaster hub
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SHIMANO NEXUS INTER-8 COASTER HUB
S S G G - - 8 8 C C 2 2 0 0
SERVICE MANUAL
1
vol.

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Summary of Contents for Shimano Nexus SG-8C20

  • Page 1 SHIMANO NEXUS INTER-8 COASTER HUB S S G G - - 8 8 C C 2 2 0 0 SERVICE MANUAL vol.

  • Page 3: Table Of Contents

    Contents The new standard in internal geared hubs Technical Service Instructions SG-8C20, CJ-8S20, SL-8S20, BL-IM65 Troubleshooting Chart Replacement of the internal unit Disassembly of the internal unit Assembly of the INTER-8 coaster hub Cassette Joint & Measurement tool NEXUS non-turn washers Hub dimensions (O.L.D.

  • Page 4: The New Standard In Internal Geared Hubs

    Many technical advances have been achieved, like incorporating Shimano’s unique gear change support mechanism that makes a real low effort shifting.
  • Page 5 • Gear Change Support Mechanism in combination with a seperate brake system such as V-Brakes. Shimano’s gear change support mechanism uses pedaling power to aid down-shifting. The result is fast and accurate down-shifting with an exep- tionally light feeling. Mechanical shifting resist-...

  • Page 6: Technical Service Instructions

    Use a lock nut with a nylon insert (self- direction locking nut) for the clip nut. It is re- commended that standard Shimano parts Driver 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.
  • Page 7 Non-turn washer 1) Secure the cassette joint to the hub (for left side) with the cassette joint fixing ring. When installing the cassette joint fixing Cassette joint ring, align the yellow ● mark with the yellow ● mark on the cassette joint Groove of fork end pulley.
  • Page 8 Brakes. Install the lever as shown in the illustra- Groove in cable guide tion. V position Hole in winder unit In case of using Shimano Leave a gap CJ-8S20 half grip, the straight of 0.5 mm JAPAN • V-Brakes section of the handlebar...
  • Page 9 Adjusting the cassette joint Pass the inner cable through the Turn the cable 60º counterclockwise SIS-SP40 outer casing through the and attach it to the hook. ➃ ➃ Set the Revo-shift lever to end with the plastic cap. Check to be sure that the yellow setting Hook lines on the cassette joint bracket and pulley are aligned at this time.
  • Page 10 5L/Brown provided with the INTER-8 shifting lever. cassette joint. case) • For maximum performance we highly ■ Cassette joint side recommend Shimano lubricants and maintenance products. ➀ Mark Set the shifting lever to • Parts are not guaranteed against natural wear or deterioration resulting from normal ➀...
  • Page 11 3) Push the outer casing on so that it securely Attach the inner cable to the pulley as shown in touches the outer casing holder. the illustration, pass the part of the inner cable which has the rubber bellows attached through the slit in the cassette joint bracket, and then Inner cable Outer casing holder...

  • Page 12: Troubleshooting Chart

    Troubleshooting Chart SHIMANO NEXUS INTER-8 Coaster Hub SG-8C20 Internal Hub Grease (For coaster brake also) CJ-8S20 Internal Assembly 20 21 22 23 24 TL-8S30 15 16 17 18 TL-8S20 TL-8S11 Same treatment of 8R20 Trouble condition Remedy Abnormal noise Cable is incorrectly Set the shift lever to 4th.
  • Page 13 Troubleshooting Chart Trouble condition Remedy Gear shift Cable is incorrectly Set the shift lever to 4th. Then turn the is not adjusted. cable adjusting barrel to align the red possible. setting lines on the cassette joint bracket and pulley. Remove the wheel Gear shifting is Replace the shifting lever.

  • Page 14: Replacement Of The Internal Unit

    Replacement of the internal unit SG-8C20 Note: Unit parts should never be disassembled. If they are, problems may result. When replacing parts, replace the whole internal assembly or whole unit part. Tools Note: c: TL-8S20 Unit parts should never be Right Hand Cone Installation Tool Part No.
  • Page 15 Remove the brake arm unit and ball retainer B from the hub axle. Brake arm unit Ball retainer B Remove the hub shell. Hub shell Internal assembly Now it can be replaced with the new internal assembly. Disassembly and assembly can be carried out quickly.

  • Page 16: Disassembly Of The Internal Unit

    Disassembly of the internal unit Remove the brake shoe unit. Brake shoe unit Carefully remove the stop ring Screwdriver with a screwdriver. Because the stop ring will tend to come off with some force, use a piece of cloth to prevent Stop ring (Y-33Y 19000) loss.
  • Page 17 Remove ball retainer O (3/16"X26) while pushing pawls B. Ball retainer O (Y-34R 98030) Pawls B Reverse axle unit in vice to access the drive side cone assembly. Remove the locknut with a 17mm hub spanner. Right hand locknut (Y-33Z 07020) Remove the stop washer.
  • Page 18 Remove the lock washer. Lock washer (Y-34R 98090) Remove the driver plate. Driver plate (Y-34R 12000) Support the driver assembly on the vice, as shown. Set cone removal tool (TL-8S11) into the groove such that the pawl A is contacting the notch in the tool, see detail.
  • Page 19 Reverse the right hand cone. Right hand cone (Y-34R 98080) Remove the ball retainer P (3/16"X13). Ball retainer P (Y-34R 98070) Remove the driver unit. Driver unit (Y-35P 98070) Remove the return spring A. Return spring A (Y-34R 21000)
  • Page 20 Remove the clutch unit by turning it counterclockwise and aligning the two teeth to the two grooves, as shown. Clutch unit (Y-35P 98060) This completes the disassembly of the INTER-8 coaster hub.

  • Page 21: Assembly Of The Inter-8 Coaster Hub

    Assembly of the INTER-8 coaster hub NOTE: With the hub axle unit mount- During the assembly procedures ed in a vice, align the two coat all seals, gears and pawl teeth on the clutch unit with assemblies with a thin coat of the two notches in the hub Nexus specific grease.
  • Page 22 Install the ball retainer P (3/16"X13). Ball retainer P (Y-34R 98070) (Y-041020800) When installing the right hand cone, align the two serrations with the grooves in the axle, as shown. Set the cone instal- Right hand cone (Y-34R 98080) lation tool (TL-8S20) and strike it until it comes to a stop.
  • Page 23 Install the lock washer. Lock washer (Y-34R 98090) When installing the stop washer, align the two teeth with the two grooves of the lock washer. Stop washer (Y-34R 09000) Tightening torque: . Install the right hand locknut 25 - 30 N·m {218 - 261 in.lbs} with a 17mm hub spanner.
  • Page 24 Install the ball retainer O (3/16“ X 26) while pushing pawls B one by one. Be careful not to displace pawls B on the driver unit. Pawls B Ball retainer O (Y-34R 98030) (Y-041 20800) How to align the three planetary gears and install the ring gear.
  • Page 25 Align the internal tooth on the ring gear and carrier unit with the groove in the hub axle unit. Install ring gear and carrier unit slowly. (Y-041020800) (Y-041 20600) NOTE: Be careful to fit A to A and B to B of the driver unit and the hub axle unit as shown in the picture.
  • Page 26 Insert the stop ring. Stop ring NOTE: (Y-33Y 19000) If there is no visible groove to receive the stop ring, it is likely that the ring gear and carrier unit are not properly assembled, (Y-041020800) return to assembly step 13. Install the brake shoe unit.
  • Page 27 Place the brake arm unit onto the hub axle and turn it Brake arm unit (Y-35P 98080) to the left and right so that Brake shoe unit (Y-35 98020) the serrations of the brake Serrations shoe and brake arm unit engage with each other.

  • Page 28: Cassette Joint & Measurement Tool

    Cassette Joint CJ-8S20 CJ-8S40 for 8 speed for 8 speed Measurement Tool 101mm TL-CJ10 for CJ-8S20 101mm TL-CJ40 for CJ-8S20 127mm TL-CJ40 for CJ-8S40...
  • Page 29 Interchangeability 8R20 type Ring gear 2 Red Line 8R25/45 type Ring gear 2 SG-8R20 SG-8R25 SG-8R45 Hub Shell + Internal Unit CHAIN DRIVE SG-8R20 SG-8R25 SG-8R45 SG-8R20 Mass production Possible not recommended standard & replacement Mass production SG-8R25 Internal Premium Unit Replacement (8R20 type Ring gear 2)

  • Page 30: Nexus Non-Turn Washers

    NEXUS non-turn washers NEXUS non-turn washers NEXUS non-turn washer application chart For right For left Reversed fork end Standard fork end hand side hand side 5R/L 5R:Yellow 5L:Brown 5R/L Good Good 6R/L 6R/L 6R:Silver 6L:White Good 7R/L 7R/L 7R:Black 7L:Gray Good Good NR: not recommend...

  • Page 31: Hub Dimensions (O.l.d. And Axle)

    Hub dimensions (Over Locknut Dimension and Axle) 25.7 132.3 66.15 66.15 C.L. 47.85 2.55 C.L. 42.85 58.3 29.15 29.15 DRIVER CAP JOINT NUT BC3/8 26 TPI BC3/8 26 TPI NON TURN WASHER NON TURN WASHER SPEC MARKING COLOR SPEC MARKING COLOR FOR REVERSED FORK END AND FULL...

  • Page 32: Spare Parts List (Sg-8C20)

    Spare parts list SHIMANO NEXUS INTER-8 Coaster Hub SG-8C20 Internal Hub Grease (For coaster brake also) CJ-8S20 Internal Assembly 20 21 22 23 24 TL-8S30 15 16 17 18 TL-8S20 TL-8S11 ITEM SHIMANO DESCRIPTION CODE NO. Y-35P 98010 Internal Assembly (Axle Length 184 mm)

  • Page 33: Spare Parts List (Sl-8S20)

    Spare parts list SHIMANO NEXUS 8-speed Revo-Shift Lever SL-8S20 ITEM SHIMANO DESCRIPTION CODE NO. Y-6FD 98010 Bracket Cover & Fixing Screw Y-6F0 04000 Cover Fixing Screw Y-61W 98030 Cable Adjusting Bolt Unit Y-6F4 09000 Clamp Screw (M4 x 23.5)

  • Page 34: Spare Parts List (Cj-8S40)

    Spare parts list SHIMANO NEXUS Cassette Joint CJ-8S40 - 8 S ITEM SHIMANO DESCRIPTION Q'TY CODE NO. Y-74Y 98160 Outer Casing Holder Unit Y-74Y 27000 Rubber Cover Y-74Y 28000 Outer Casing Holder Y-74Y 30200 Rubber Bellows Y-74Y 98140 Cassette Joint Unit...

  • Page 35: Spare Parts List (Bl-Im65)

    Spare parts list SHIMANO NEXUS Brake Lever BL-IM65 For Left Hand / 3-Finger ITEM SHIMANO DESCRIPTION Q'TY CODE NO. Y-8TS 98020 L.H. Adjustment Block & Screw Y-6JB 98040 Cable Adjusting Bolt (M10 x 19) & Nut Y-89E 05010 Reach Adjusting Screw (M4 x 10.8)
  • Page 36 Phone +358 20 1550 800 +358 20 1550 801 MACARIO LLORENTE, S.A. Spain Phone +34 91 329 5070 +34 91 329 2594 / 91 329 2039 Specifications are subject to change for improvement without notice. MA34RA © February 2005 Shimano Inc.

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