Originally Posted by
Storm Knight
Rear derailleur is Shimano 105. Rear cassette is a 9 speed. Front derailleur and brakes/shifters are Tiagra. Don't know model of front chainring (which is a triple), as there is nothing on it to indicate brand/model that I can see.
As someone else mentioned, those are quality components and chances are something is just out of adjustment or maybe worn. If the derailleurs are properly adjusted, probably need to replace the chain, maybe the cassette and/or chainrings.