Hey guys, I am new to cycling and I bought a used Diamondback Sorrento. I dont know what year it is but its a few years old. I LOVE the bike, I ride it through the trails around my school and all throughout campus and the local area around Orlando/Oviedo FL. I don't know much about bicycle repair but I would like to learn. I am having trouble with my chain slipping here and there in the lower gears. I want to get a new cassette and chain, but I don't know what kind to buy. Does anyone have any ideas? I would also like to order it online. Do you know any good sites?