Now I have got the bottom bracket out, I have properly inspected the chainset and the teeth are worn in quite a few places, so I am thinking while its off replace it, my question is I am looking at xt770, the bottom bracket I have taken out is BB-UN-26E73/113mm, so on the xt it says comes complete with bb for 68 and 73 frames, so if i tell them its 73 will that fit mine, and I also bought a removal tool for my original bb today will that fit my new one? Sorry to be thick but always used shop in the past, but always feel ripped off

You’ll need a new tool to fit the bb that comes with the xt770 chainset and also a tool to fit the bearing preload cap. The bb will fit both 68 and 73mm shells, you just need to fit the appropriate number of supplied spacers.

Right then. The XT chainset you’re looking at is the new external BB one, I think the one you’ve just removed is an Octolink internal cartridge BB. Different thing all together.

You’ve two options.

1. buy new Chainset (it comes with a BB that WILL fit your bike) job done. Expensive way of sorting problem

0r

2. Buy a new BB like the one you have already, and some new chainrings to fit onto the existing chainset. Cheaper.

For the XT770, you’ll need one of these
http://www.chainreactioncycles.com/Models.aspx?ModelID=10179

The BB, cups, spacers you need all come with the crank. That one tool is all you need for fitting as it has the BB cup tool and the bearing preload cap tool combined.
You also need a rubber mallet to whack it in place.

Get a SLX chain set and tools.

I think that’s a square taper BB, though the number is slightly different to the one on mine (EBBUN26BB13X)

Guy in a LBS quoted me £30 for a Deore Octalink bb to replace my old LX one, and they had to order it as its “older technology”. Ebay had some nice LX ones new for about £15 some time ago, 113mm as I got mine from there (just love my older XT cranks and dont want to replace them). Than You can get some replacement rings or buy a new cheap chainset just for the rings.
That would be a cheaper option.

Buying a new chainset with a external BB would be a bit more expensive (if You go for an XT) unless You buy new Deore with the external BB than it probably would be about the same as a new octalink BB and a reasonable set of rings. Depending on what cranks You are running now.

“Sorry to be thick but always used shop in the past, but always feel ripped off”

Not thick at all. In fact quite enlightened.

Completely unpatronising virtual pat on back.

the teeth are worn in quite a few places

Are you sure you’re not confusing “wear” with “shifting ramps” (the slightly smaller teeth used to aid gear shifting).

I agree with Dibbs. It sounds more like you are looking at the shift ramps which many new bikers mistake for chainring wear. Chainring wear happens all the way round, and you can get away with a lot of wear. The teeth become more like stars and start to not pull the chain so snuggly. On my commuter, I can pull the chain backwards and forwards and it slides slightly around the chainring it’s that worn, but still rides ok.

You cassette and jockey wheels are more likely to be worn first IMHO.