Originally Posted by
cyclezealot
It's in the teeth , look for rounded edges.. I just had to replace my rear cluster. Before it was changed, I had a constant problem with the chain falling off the smallest cog and getting jammed between the quick release and the cluster...
That sounds like more of a derailleur problem than a cassette problem... A properly set up derailleur wont let a chain fall off a cog. Your cassette would have to be worn down so much that there were hardly teeth left on it, for that to happen!
OP: time for a new freewheel and the two largest chainrings. If you can find out what the BCD (bolt center diameter) is, you can easily find new chain rings for it! The smallest ring looks fine, to me, but It probably wouldn't cost much more to replace that, too. The crank looks fine, just needs new chainrings.