Can I Do This? Can this bike be turned into a nine speed?

Question

I bought this bike a few weeks ago because it was on sale, and now I want to make it a nine speed. The link is http://www.marinbikes.com/2008/us/bikes/specs_alpine_trail_29er.php

Answer 1

Yes. In addition to replacing the cassette you'll need a 9 speed shifter and a longer bottom bracket spindle.

Um, this swap may cost almost as much as the whole bike and you really won't see a performance difference.

Answer 2

Yes you can.  Remove the 8 speed cassette and install a 9 speed cassette.  Then you will need to purchase a 9 speed shift lever.  As far as I know, all you will really gain is a slightly lower low gear.  I have a 11-32 8 speed cassette and a 11-34 9 speed cassette.  Not much difference.