I bought a used 14 speed trek 5200 oclv(7speed shifter). Need to know if i can upgrade that to an 18 speed(9speed shifter). Do you know what year model this bike came out ? Has the shimano 600 components in it. Thanks a lot for your help.

You will need 9 speed shifters, 9 speed rear derailleur, 9 speed compat. chain, 9 speed cassette. I have actually heard that you need a 9 speed specific inner chainring to make it shift flawlessly.

That would be a first generation OCLV frame. The early ones also had aluminum forks. Switch to carbon was in the '95 time frame starting from the 5500 and then migrating to the 5000 OCLV in '96. If you can time when
Shimano intro the 8spd system that would give you an recent limit. Steve