Expander nut for mounting front bike fender

thingiverse

Mounting the Decathlon's front bike fender requires a specialized nut-expander. The standard stock nuts-expanders are designed for tubes measuring 19-24mm and 29-35mm, but my tube is narrower at 17mm. To secure it in place, you'll need to use an M5 nut paired with a screw that's at least 35mm long, both of which come included with the fender.