I took my bike in for a tune up and to have a broken chain and ready to die rear derailure replaced/upgraded from a LX to XT, the chain is a Sram alittle nicer then my current chain. I picked it up today rode it around the lot and took it back in since it had bad chain suck and threw the chain when I upshifted to the big front chain ring. They claimed that the bike not shifting easily from the small front chainring to the middle (need to push lever way beyond normal point, and the bike making noise when I was in the small chainring were normal though the bike didn't do it before. When I took it home and rode it more to get it better I also noticed when pedeling hard in the two smallest rear cogs causes the chain to jump between gears. What is causing this, these are the only things I can think of. 1. improperly adjusted derailures 2. chain length incorrect 3. the mix of three year old well used front and rear cogs with new chain and rear derailure. 4 They are correct about the noise in the small front chainring and hard shifting. Any suggestions before I take it to a seperate shop for a second opinion tomorrow to see if they can figure it out, but I would like some background before hand.