epicyclo – Member
If it’s disk brake, check your pads.
The little retainer spring can sometimes get caught on debris and bent out if the pads are worn enough for it to be close to the surface.
It will make an irritating noise like you have described and be very difficult to trace because it doesn’t appear to emanate from the disk.
I thought I had a spoke coming adrift…
I’ve had that.
I’ve also had the end of a cable tie that was holding on a chainstay protector rubbing my shoe as I pedalled. Drove me mad, because when I got off the bike to check what it was, it wasn’t happening. Get back on, it was back.