On my Day One Alfine, which has probably only done roughly 1500 miles, the chain seems very "loose". I'm assuming its worn. It flexes over an inch up/down easily. The chain tensioners have been adjusted as far as possible.
Is a 9spd chain wear checker a valid tool for checking it? Rough measurement shows 12 full links is about 12inches and 1 16th.
So. Is it replacement time, or can I just remove a link and bring the tensioners back in? Sprockets look OK, but I've no idea really.
I used to get a similar problem but I had tight spots on the chain too. I eventually narrowed it down to a faulty rear sprocket. It was slightly elliptical. I found the chain tugs system to be fiddly and annoying so I switched dropouts and use a conventional tensioner and have had no problems since.
I doubt it's worn already. Try checking everything is how it should be. Maybe it's just stretched a little and needs shortening.
