Last night after a short ride with my wife, she was complaining that her shifting was "just not right." Her bike is probably about 8 years old and I don't think it's ever had a tune-up. I've been wanting to practice some mechanic skills for awhile, and she gave me the green light to put on new cables and adjust the derailleurs.

For my first time doing all of this all was going fine, until I was making the final adjustments to the rear derailleur. Here's what's happening: the shifting seems fine - the chain runs the range of the cassette without a problem, and without wanting to jump either up or down. Front derailleur seems to be fine too - no rubbing on either the high or low chainring. The problem, however, is that as I turn the crank by hand there is quite a good amount of noise coming from the rear cassette area. Plus, the crank doesn't turn smoothly - it has a very noticeable hitch as I pedal it forward by hand, and it feels almost as if the links in the chain aren't matching up with the teeth in either the pulleys or the cogs.

It's a triple chainring configuration and the parts are 8 speed Sora.

Please help!

Thanks!