DI2 Fitment

[Manguish]

No idea on this so I'll throw it out there. Cheers for any advice.

I have a cannondale supersix with sram (apex I think).

Let's say I fancy the electronic upgrade, can I simply throw the stuff onto the bike and it will work with the sprockets et all as it stands, or is it full system, sprockets the lot required?

Secondly, what's a braze on? Surely you can't braze to carbon?

 

[Mr Haematocrit]

You can if you choose keep your crank, ring gear and cassettes. It works better though with the entire kit from my experience, or Di2 specific components.

1. Braze-On': Where the front mech bolts directly to a slotted mounting plate which extends from the seat tube of the bike. There are not different sizes for this type of mech which makes it easy to purchase the correct product. Also, adapters are available to convert a braze-on mech into a band fitting as below.
2. 'Band-On': Where the mech has a clamp that closes around the seat tube. The size required depends on the diameter of the seat tube on the bike. You must measure this accurately to get the size, or best is to have the old mech as the size is usually stamped on it. There are three common sizes, 28.6mm 31.6mm and 34.9mm although manufacturers now make multi-fit options that just use shims, included, to adjust the band size.

 

[Mr Haematocrit]

There is also a Di2 specific thread which may answer some of your questions

http://www.cyclechat.net/threads/shimano-di-do-and-do-not.112006/