What derailleur and chain shall I get?

Hello, I have a question.

A couple of weeks ago my chain begun to get very stiff and because of that it took effect on the rear derailleur. I have a Trek 1.2 series bike(I am a beginner) and I was wondering what rear derailleur and chain would suit this bike. Thanks for the help.

 

Not to hijack, but are rear derailleurs all that specific? Though transferring to 10-speed, I plan to keep the Shimano RD from my 7-speed.

 

Yes. There's the possibility that the amount of cable pull the derailleur is intended to work with could be different, causing shifting issues. If the new derailleur doesn't move the same amount per shift lever accuation as the old derailleur, you're going to have problems.

http://sheldonbrown.com/drivetrain-mixing.shtml

 

Thank you AyeYo.

 

In the Shimano lineup, all road rear derailleurs made for 8-, 9-. and 10-speed indexing have the same pull rate. All MTB rear derailleurs made for 7-, 8-, and 9-speed indexing have the same pull rate, which is the same rate as for the above-mentioned road systems. Road 11 and MTB 10 are systems unto themselves. Regarding front derailleurs, it's best to match the unit to the chain (7-8, 9, 10, or 11). And mixing road and MTB front derailleurs with crankset and shifters is an ugly can of worms that I'd rather never touch again for as long as I live. At least while I'm on the clock or somebody is waiting for it.

 

Thanks AyeYo and oldbobcat!

 

Minor correction: Old Dura-Ace 7- and 8-speed is not compatible with the newer stuff (Ultegra 8-speed, Dura-Ace 9-speed, and up). Your old 7-speed Shimano derailleurs most likely will not work. Try and see, but don't stay up all night.