TSB-001 torque support arm on postmount frame

Date Page(s) Components/parts Markets Name Version
24/04/24 1-2

MTB torque support arm TSA-000U-A00-A-00


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OEM Global


1.0 2024



1. Subject

Notification of correct installation of the MTB torque support arm and application of the frame protection plate on postmount frames.


2. Affected components

Below specified torque support arms on postmount frames with the ETS 142 and ETS 148 Classified Powershift hub.


Product name Article number Internal reference Classified
Torque Support Arm - ETS Only: MTB TSA-000U-A00-A-00 029_071_04


3. Situation

Context reason

We have seen cases of paint or frame damage that are linked to not following the installation procedure.


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After installing the Classified Powershift hub on a bike with postmount brakes, the torque support arm should not touch the frame directly. To prevent frame damage, a frame protection plate should be installed in between the torque support arm and frame to protect the frame.


For frames with a drain hole or suspension pivot point in the chain stay, extra caution is necessary. The torque support arm should not be close to these points.


4. Procedure

  1. Check how much room is available at the frame dropout of the non-drive side. I.e., make sure there are no obstructions such as drain holes, suspension pivot points, … in this space.
  2. Check that the Powershift hub has been fully assembled and attached in the hubshell.
  3. Slide the torque support arm onto the Powershift hub.
  4. Clean the frame dropout of the non-drive side rear fork with degreaser or alcohol wipes.
  5. Mount the wheel in the frame. Gently tighten the smart thru axle such that the wheel is fixed in place while the torque support can rotate freely. 
  6. Rotate the torque support arm until it touches the frame, to locate the area where you want to mount the frame protection plate.
  7. Remove the paper backing from the protective tape.
  8. Stick the protective tape onto the frame at the place where the torque support could touch the frame.
  9. Press on the protective tape for 30 seconds to ensure good adhesion. 

    WARNING: The protective tape is subject to wear and tear. We recommend checking the protective tape for wear and tear after each ride, while cleaning your bike. Loosen the thru axle and remove the torque support arm from the frame to inspect the protective tape. If the protective tape is worn through, replace it. 

  10. Double-check by repeating this procedure to confirm that you installed the torque support arm correctly.
      • If the torque support arm touches the frame protection plate, then it has been installed succesfully.
      • If the torque support arm is blocked or is close to an obstruction (drain hole or pivot point), it has not been installed successfully. Please contact Classified Cycling.


5. Identification method of postmount brake callipers 


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Beschrijving automatisch gegenereerd met gemiddelde betrouwbaarheid


  1. Look at the frame from the back, at the level of the frame dropout. 
  2. Check how the brake callipers are installed:

    A. Postmount frame: The brake calliper is attached with screws through the top of the frame. Always use a frame protection plate between the torque support arm and the frame as explained under paragraph 4.

    B. Flatmount frame: The brake calliper is attached with screws through the underside of the frame. No frame protection plate is needed.


NOTE: this technical service bulletin is only applicable for postmount frames. These instructions are not meant for flatmount frames.


Classified cycling general terms and conditions and warranty policy apply.

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