Upgrading Chainset & Front Mech

by DanSmernicki   July 18, 2011  

I'm thinking about gradually upgrading my current transmission..
Currently on a Giant SCR 3 (2007) with Tiagra Rear Mec, Sora triple front and a generic crankset...
I'd like to upgrade to 105, probably starting with the chainset and front mech. Are there any compatability issues I should be aware of? And will I need to change the bottom bracket too?
Grateful for any advice....