I found a thin plastic tool, about 5cm long. It is engraved with the number 5. I believe it to be a bike tool. What is it?

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  • 1
    somthing to do with brake pads ?
    – Max
    Jan 16, 2020 at 15:23
  • 1
    @Max Correct, it's a spacer to be inserted between the brake pads while the wheel is removed.
    – linac
    Jan 16, 2020 at 15:28

2 Answers 2


As linac said: "It's a spacer to be inserted between the brake pads while the wheel is removed"

Andy P has explained why the spacer is needed.

There are a variety of spacers made to work for different disk brake designs.
Here are two examples:

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Here is a picture of the spacer being used
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  • This is a good answer - would you like to post it on the duplicate as well? Its easy to find the parent question from the dupe, but not very easy to go the other way, and reposting this higher up the tree will help.
    – Criggie
    Jan 17, 2020 at 1:29

It is a brake pad spacer.

It is designed to go between the brake pads when the wheel (and hence rotor) is removed.

This is because most hydraulic disc brakes are self adjusting, and if the lever is squeezed accidentally with no rotor/spacer in place, then the pistons will extend too far and then not retract far enough. This then causes problems with rubbing brakes, or in bad cases, makes it impossible to re-fit the wheel.

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