Looking at Sheldon Browns Gear Calculator got me wondering about drive train and drive train components. My Fuji Absolute has a crank set with 48, 38, and 28 tooth chainrings and an 8 spead cassette 11 - 32. The crank set is sunrace, derailluers and shifters are shimano. So if you upgrade some of your components, can you do it one at a time, or should you change the whole set? For example, many of the upgrade derailluers I see on JensonUSA are for 9 and 10 spead cassettes, can these be adjusted for an 8 speed or do you need to upgrade your casstte and shifter at the same time. No very many shifter options either in 8 speed, so if you want to upgrade beyond Deore, will a nine speed shifter work on an 8 speed derailluer? I am not planning on making any changes on my bike right now, may just even upgrade bikes at some point as I am really liking riding and I am getting more of an idea of what I want, but it is possible I would eventually like to just upgrade componenets as I do like the frame, adjustable stem and forks on the Fuji.

Jimbo