In reply to TobyA:
> (In reply to contrariousjim)
>
> I'm presuming its a square taper one? ie. once you have got the the chain set and other crank off there are tapered square things protruding that the cranks sit on?
Yes.
> If so, changing a BB the first time you do it can be a hassle mainly because you need to get the right type of tool to get the cups things out and I've found they can be super stiff. Lots of washing and WD40 or similar helps. Then once you've got the bugger out you need to work out what size it is if you don't have a legible sticker still on it. I ended up buying my first vernier caliper to do this (and of course then having to look up on the internet how you read the thing!) then you have to work out where the measurement is taken from on the BB. Once you've done all that (which I remember taking bloody days and necessitating various trips to the DIY/bike bits store for the tools), then just go on Wiggle or whatever and order the part! Putting a new one in is a piece of pee in comparison! Once you've done it the first time and you have the tools, it's easy to do in the future although invariably future bikes will have a different BB type (my road bike does) making your tools and hard earned knowledge totally redundant.
>
> Good luck and have fun.
Thanks. The more I learn about and work on my bike myself, the more fun I have! This is my bike...
http://www.bikepedia.com/quickbike/BikeSpecs.aspx?year=2005&brand=Giant...
...albeit with lower specced components, e.g. deraillers, wheels, etc, but that gives the basic information on the BB:
Bottom Bracket Sealed cartridge, 113mm spindle
BB Shell Width 68mm English
I think the tool I have is the right shimano BB tool, but it just shredded the teeth on the plastic cups when I was removing them, but I got the cups off ok. I just don't think it'll be possible to put them back on, so will need the cup bits, but it looks like the come with the sealed BBs?