hi, sorry for the stupid question.....
i am a newbie on bikes, and have 2 problems...
when i change to the middle chain ring on my mountain bike it rattles and struggles to get in...any ideas?
also on the back sprocket i cant select the biggest cog, it says i'm in first on the gearshift on the handlebars, but wont go in at all?
again sorry for the really basic questions
thanks in advance
bike is 21 speed mtb