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repair rear mudguard bracket fitting

  • 29-01-2023 1:35pm
    Registered Users Posts: 14

    Hey, the rear mudguard on my mountain bike has been loose for ages but I could not tighten the nut as the actual screw fitting on the frame is blown. The screwnut came apart from the frame/holder part. Of course this is supposed to be one fitting but I wonder what it is called and if a replacement can be found?

    This is a picture of the little thing;


  • Registered Users Posts: 167 ✭✭Al Wright

    Probably an M5 (5mm thread) 'Rivnut' or 'pop nut'. It is inserted into a 7mm dia (approx) hole and then tightened up using a dedicated tool. Local bike shop or car repair shop may have them and the fitting tool.

    They can also be fitted using HT or stainless steel bolt & nut and a few washers as illustrated in attached sketch.

  • Registered Users Posts: 934 ✭✭✭nicksnikita

    Yep looks like a rivnut. Nice DIY job if you're that way inclined

    Also, if any other rivnuts on the bike are loose (bottle cages or other mudguard mounts for example), you can use the above assembly to tighten them up in situ.