correct bb size

biggs83

Hi guys
After building my new frame, im having trouble with my front cogs and bb. I took it to my lbs and they have told me my bb is a little to short and he was only able to get the front mech to work in the middle and large rings. When I bought the frame the previous owner said that the bb size was 68-113mm. Can anyone advise on what I should do as I dont mind getting a new bb and chainset as mine is fairly old and how to measure correctly (the bike is a 7 speed if that helps)
Many thanks
Rich

cooldad

Depends on the crankset you have - you need to look at the manufacturers tech docs. The LBS should have been able to work that out.
Alternatively you could fit a new crankset like a Shimano Deore with an external BB. You should have the BB shell faced though.

biggs83

Looking at it I think I might just get the guy to do it for me. He did give me advice and their very friendly down there so i guess it will make sense for for them to do it. At the moment I have a cheap square taper one on old crank arms. I have been looking at all the different types of bb and noticed the hollowtech 2 system. What are they like to ride on as i've only ever used the sealed style
many thanks

cooldad

Nice and stiff, but the BB's don't last as well as cartridge types. Deore are absolutely fine, and when the BB dies replace it with an XT or XTR. Easy to work on.