Just went out for a morning ride, didn't get more than .5 miles away when it became apparent that the rear deraileur just couldn't figure out where to slide the chain. It was hopping all over the place. About the only time I could get it smooth was on the smallest and largest. What sucks is it's a brand new ultegra on my brand new trek 1500. Is this something I can adjust or should I just take it back to the lbs tomorrow and have them take care of it. I wanted to ride today.....
You derailler just needs a minor adjustment. The cable housings probably seated a little further in the stops and you need to tighten the adjuster a bit. This is normal with a new bike and your LBS can fix it in a few seconds. Ask the wrench to show what he's doing so you'll know how to do this yourself in the future.
As noted this should be a very simple adjustment and is not an unusual problem with a new
bike. Go to www.parktool.com and on the left click "Repair Help" and click on the top box
"How do I work on my bike?" You can then click on the rear der on the bike image or
scroll down to the topic ""Derailleur and shifting" and read the section on indexing the
rear derailleur. Probably the H and L stops are already correct but this is easy to check.
Doing this with the rear wheel on the ground is not easy but the absence of a stand can
be remedied by hanging the rear wheel off the ground with a rope to the seat from over
head. Once you have done it you will find it is very easy to adjust. Steve