i just bought a 21 gear mtb and the chain is quite rusty so i need a new one. but when i go to ebay im just getting confused because it says things like shimano 5,6,7,9 or 10 speed chain. so i dont know which one i need
This is where bypassing a bike shop fails you.. they will sell you the right chain and dissolve
your ignorance of common terminology, and for a modest cost even put it on for you.
but the basics, math, 21 is what? 7x3, right? do you count 7 cogs
stacked up on the back wheel..?
your first hint...