Hi all. So I was commuting to school as usual... I shifted into first on the rear... when all of a sudden I was free pedaling. I checked my rear derailleur and found out that the chain fell out of place from the tallest cog.
My rear cassette somehow moved away from the plastic flywheel. The The chain gotten looser as well. If I shifted to a higher speed (rear), the chain would not have enough tension, and so it would begin slipping among the cassette teeth.
So, my rear cassette is loose (The tallest cog actually freely wobbles and turns in place). I have no idea on what might have happened. I guess something of the sort needs to be tightened... but what?
2008 Novara Randonee - love it. Would have more bikes if I had time to ride them all. Previous bikes: 1968 Motobecane Mirage, 1972 Moto Grand Jubilee (my fav), Jackson Rake 16, 1983 C'dale ST500.
In my opinion you need to take this to a shop. The cassette has nothing to do with chain slack not being taken up when on the smaller rear cogs - that's a function of the rear derailleur - so you have at least two things wrong, possibly some sort of damage that occured just before that ride.