What size bottom bracket?

[grahammackie]

Have just bought a new frame to make up a second 'training' bike and have purchased a FSA Gossamer crank with 175mm arms.

As the bike has never been fitted out before I have no idea how I choose the BB size. It is a 68mm sheel but how long does the shaft have to be ?

Any help gratefully received

[DiabloScott]

Have just bought a new frame to make up a second 'training' bike and have purchased a FSA Gossamer crank with 175mm arms.

As the bike has never been fitted out before I have no idea how I choose the BB size. It is a 68mm sheel but how long does the shaft have to be ?

Any help gratefully received

Get the English treaded FSA BB for a double crank and you can't miss

[fish156]

Have just bought a new frame to make up a second 'training' bike and have purchased a FSA Gossamer crank with 175mm arms.

As the bike has never been fitted out before I have no idea how I choose the BB size. It is a 68mm sheel but how long does the shaft have to be ?

Any help gratefully received Usually, picking a BB will be determined by the BB shell width & threading, the length of the spindle (depending on whether you are using double or triple chainrings), and the correct mating type to match the cranks.

But, the FSA Gossamer MegaExo cranks (MegaExo, Compact MegaExo, and MegaExo Triple) all use a common BB - with the only differences being the correct match for your frame. So, you need the MegaExo BB (68mm, English threading). That makes it easier than usual ;-) Here's the reference:

http://www.fullspeedahead.com/fly.aspx?layout=product&taxid=29