right now i have a pretty basic mountain with a 24 speed, which i like for climping up mountains, yet i cant seem to find online when looking up bikes i would like to buy a new full suspension mountain bike for doing single track. i want a good gear ration so i can do climb as well . but im not sure what i need when i try to look up bikes all i come up with is Rear Cogs, 9-speed things like that . what does that mean and what would be best for me. thanx