Originally Posted by
alcjphil
Out of curiosity, where did you get the information that your shifters are the ST-5600 series? If it came from the original specs for the bike, there is no guarantee that the information is correct. Buying a bike is a learning experience. It is very unlikely that the bike shop would have been able to get a 9 speed cassette to shift properly if you have 10 speed shifters.
I pulled aside the rubber cover of the shifters (the hood I think). It was on the outer side of the shifters. I'm not exactly sure what happened so I trusted that the mechanic. And I'm not blaming him for anything as it is my fault for not doing any research.