I got a bike from free cycle that I am cleaning up for a student of mine who is in desparate need of transportation. It's an old huffy mtn bike that has been kept inside except for last winter . They said it needs new tubes. The back tube is pulled somewhat out of the back tire, which leads me to believe maybe they didn't understand that you have to actually remove the wheel from the bike to change the tube! There is a little rust on the wheels and chain. I am going to attempt cleaning both but I may replace the chain. Other than that, a quick clean and lube and it should be good to go. I only have changed a chain on a single speed. It was raining when I brought the bike home. I know it is 18 speed sram. How do I know what size chain to get? I am off to garage sale for a back rack. Hopefully when I get back, I will have some chain answers!