I have a Jamis Aurora. It's got Shimano Tiagra brifters. On the cable that comes out of it, there's a little twisty knob. I'm just curious what that does?
It's a barrel adjuster, for changing cable tension to tune your derailleur.
You can mess with it experimentally; twist it and watch which way the rear derailleur goes. Then you can tune as you ride.
NEW Ritchey Pro 27.2 x 350 x 25mm-offset seatpost
NEW Dura Ace 7703 9-speed triple 28.6 front derailleur
USED Ritchey Pro 30deg 110 x 31.8 stem
USED Specialized Comp 20-28deg 110 x 31.8 adjustable stem
If you experiment, note the relationship of the two parts BEFORE you change anything. That way, if you make the shifting worse, you can return to the original setting before experimenting further.