“Only when pedaling” Have you checked to see if you still hear it when pedaling out of the saddle? If it doesn’t, then I would also check the seat clamp (and maybe the seat post too). Take the seat completely off the clamp, check for, and clean the seat rails and clamp. A small bit of corrosion in there can cause the connection to become ever-so-slightly loose. As your body slightly weight shifts side-to-side when pedaling, it makes the seat move just enough to produce a ‘noise’ from there. If it makes the noise when you’re pedaling out of the saddle…check the headset, handlebar connections.

Dan
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