First confirm the mounting bolt is not bottoming out before the mirror base is secured—a bolt can feel fully tight while the mirror stays loose. This usually means the bolt is longer than the available threaded depth.
Check the thread depth of your handlebar and compare the supplied bolt lengths. Use the length that secures the mirror base without reaching the end of the threaded hole.
For a step-by-step walkthrough, see our Bar-End Mirror Fitment Check guide, or read a documented Triumph Street Scrambler case where a shorter M6 × 20 mm bolt solved exactly this problem.
