i have a cheap road bike thats rear wheel is completely unusable. i bought a new wheal and cassette for it, and one of the gears on the cassette broke. So i went to my local bike shop and bought a new cassette, there they told me a lot of things that i dont quite understand and want to make sure i do before i install this new cassette.
the chain thats on there now came with the bike and what was on that was a 7 gear freewheel, along with a shimano index system rear derailer. now this cassette im putting on is a 9 speed shimano.
I dont quite understand all the differences between chain and stuff so i just want to know if it will ruin anything? or do i need a new chain and derailer. just dont want to brake anything else.. thanks