So some of you may remember my recent thread about building my own bike:
http://www.singletrackworld.com/forum/topic/should-i-try-and-build-my-own-bike

Well tonight decided to have a go, but with the intention of taking this very easy so I don't go wrong or get stressed. I have another bike to ride in the meantime which is just as well!!

So removed bars and stem from old bike and shifters ready to go on new bike.

Now the cranks and bottom bracket – quite hard work, but I managed it!

Intended to use old crank arms and maybe bottom bracket. I realise that I have the old square bottom bracket which is in poor condition. I will have to replace with this:

http://www.jejamescycles.co.uk/shimano-un73-bottom-bracket-73-110mm-id6053.html

Its the right bottom bracket width but what about the axle length – is this ok?

I'm going to run old middleburn RS3 cranks and have worked out that that the axle length is approx 109mm (but can't remove at moment as haven't got the right tool). Can anyone give me a definitive answer on this – think it may have something to do with the chain line??

cheers

Need to measure the width of your new bike's BB to know for sure if it's 73mm. Don't know about the axle width though – the Middleburn website may be able to help, but I do know it needs to be spot on to work best.

Yeah, I measured it – exactly 73mm

Realise I have RS7 cranks so probably need a 113mm axle length according to middleburn website, although going to run a double and bash guard – any thoughts??

Got a 73/113 set up on mine, much narrower and you may struggle with the front mech going into the small ring(newer mechs seem to be set up for a wider chainline than older ones).

cheers coatsey
dont suppose you know where i can get a 73/113 xt square bottom bracket
also 5 arm bash guard for 36 tooth chain ring??