I noticed on my last ride that when I shift the rear cogs from the larger cogs to the smaller cogs it's not a smooth shift. I took it home and shifted and watched what was happening, it seems when I shift there is a little bit of slack in the chain.

When I shift in the other direction is smooth as always, just when I'm putting the bike into a harder gear I'm having this issue. Any ideas on how I can adjust the rear derailleur to improve this? It just started happening and it's driving me crazy! Thanks so much.

I had the same problem. I ended up looking at the cable and it had a slight bent to it that made a big difference. I would adjust the cable tension on the back and see if that works. Good luck. It is pretty annoying.

Thanks man, I woke up early to get to the shop to let the pros look at it, checked it before I left and the clicking sound was gone. I did use a fair amount of dry lube last night, I'm wondering if I just needed some extra grease on it.

I second trying the barrel adjuster on the derailleur.