Joined: May 2009
Posts: 1,208
Likes: 2
From: Whitestown, IN
Bikes: Fisher Opie freeride/urban assault MTB, Redline Monocog 29er MTB, Serrota T-Max Commuter, Klein Rascal SS, Salsa Campion Road bike, Pake Rum Runner FG/SS Road bike, Cannondale Synapse Road bike, Santana Arriva Road Tandem, and others....
Bar ends and a closer ratio rear cassette.
Mountain bike cassettes generally are "wide ratio" and have larger jumps between gears and lower ratio top end gears. A road cassette are generally "close ratio" and have gear ratios closer together making it easier to find the most efficient gear available and higher ratio top end gears allowing higher speeds.
On my commuter mountain bikes I run a 11-24 or 12-26 rather than the 13-32 commonly found on lower end and mid range mountain bikes, but you will need to sit down and figure out what you need based on which of your existing gears you are using most and which ones you aren't using at all.