I'm a about to install a Shimano Ultegra groupset on my road bike, but I have found a little rounded plate with a sticky band on it, and I don't have any idea of what it is and where to put it.

Plate 1

Plate 2

How and where can I use it?


1 Answer 1


This part is called a backup plate and is used in conjunction with the front derailleur. The backup plate is mounted on the frame where the support bolt is located. Consult the Shimano installation instructions for more information.

  • 2
    that's it! thank you for giving me the direction. found a full explanation here
    – yesh
    Commented Jul 26, 2023 at 16:06
  • Indeed it is. Besides the obvious mount point for the front derailleur, on this model FD there is a screw that is driven toward the seat tube until it rests on it (or slightly flexing the FD away from the seat tube). This provides a much more solid indexing point that will not flex due to different amounts of cable pull. However, it is a small contact point, and using the backup plate (the flat or curved one, depending on the shape of the seat tube) allows the support bolt to push against the plate, and not dig into the frame. @yesh - that is a nice video you linked there, very thorough.
    – Ted Hohl
    Commented Jul 27, 2023 at 2:38
  • @TedHohl It also prevents damage to the frame (especially for carbon).
    – MaplePanda
    Commented Jul 27, 2023 at 6:30

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