I'm transforming a hybrid into a cross bike, and my next step is the bars. Before I can take it to my LBS for drops, I need to get some shifters, which I simply can't afford new (wish I could). The bike I have is a TREK 7.5 FX, which has Shimano components. It is a Triple front, 9 rear setup, and I see all kinds of options on eBay for slightly used and new shifters, but I want to make sure I get the best I can get, that will be compatible, for the best price.
Can someone help me understand the difference between:
Is one model better, or just a newer series? Better materials, or more durable? I may have even seen a 5501? Which should I get if I have the option? Are all compatible if I see one that is just way cheaper?
What about Dura Ace and "FlightDeck" compatible?
Do I have to get a 9 speed shifter, or will a 10 speed shifter work with a 9 speed rear cassette?
If you run 9-speed, get the 9-speed shifters. Shimano 105 is 55xx, any will work, double or trouble. Shimano 10-speed is 56xx, any will work with 10-speed cassette, and 10-speed chain. Flight Deck shifters have buttons and wires to work with their proprietary computer with gear combination display. Dura-Ace components are the top-of-the-line Shimano. D-A shifters are double/triple specific, the double shifters won't work with a triple.