I am a new member of this forum
The reason that I joined is I want to learn how to repair/replace parts in my bicycle
Anyway, so my bike model is Schwinn Solution FS AL and I bought it on 2006 so it's pretty old
So I am thinking about replacing gear and also chain because my chain is too rusty
My gear model is "Top Swing SIS 050 Shimano" and it's
I was searching around and I don't think I can really get the same gear
So I was wondering if I can use another gear instead of the one I have?
If so, could you suggest me the gear I can use?
Also, is that gonna be hard to replace the gear?

I am very new about replacing/repairing my bike so sorry about a lot of questions.

Thank you so much