I am trying to figure out what is wrong with my bike, i dont know if its the derailleur or if its the shifter. I assume its the spring in the rear derail. Ok here is the deal, my rear derailleur will shift from the small cogs up to the biggest ones just fine, now if i want to go back down into the smaller cogs on the cassettte it will just stay on the biggest one as i try to click down, but i dont hear a clicking noise. I can get it to shift down if I pull really hard on my shifter cable and then shift, but otherwise its a no go. Also if I release the pinch bolt for the cable the rear derailleur does return to the smallest cog just fine. I'm lost at to what to do and what to replace, If it is the spring in my derailleur are those easy to replace? and where do i get the parts for a shimano xtr rear derailleur?
Your help is appreciated