Quote from: RadMichi on June 23, 2021, 02:30:53 AMWhen starting I have every time a rather loud clack. This clacking noise always comes when the chain is not under full tension, so if I do not fully pedal. Also when loosely pedaling it often clacks.
Are you in the lowest gears (1 or 2) when this happens? My Mini ST2 sometimes clicks, noticeably but not loudly, in the very lowest gears - my bike shop guy and I both think it's due to the chain being at a pretty severe angle to the front and rear sprockets in the lowest gears because the distance between them is so short (it's easy to see if you leave it in first gear and look down from above). So the chain is trying (and usually failing) to slip off the rear sprocket to a higher gear. I'm only rarely in 1st or 2nd gear; once I upshift the noise is gone as the chain angle straightens out.
It's just the bike's geometry and nothing to be done about it, if your issue is the same as mine, and it shouldn't be a problem. If it happens a lot, perhaps your derailleur needs a bit of adjustment.