Di2 cable routing + Praxisworks BB on non-Di2 Cdale frame

[havana]

I own a Cannondale Supersix (my 2010) non-Di2 frameset.

I'm thinking about buying a full (that is, including crank) Shimano DA9070 groupset. To make the crank fit in the BB30 frame, I'm thinking about a Praxis BB.

Would it be possible to internally route the cables? I understand I need to drill at least 3 holes, which will be the easy part. I'm struggling a bit how to make it work at the bottom bracket area. The current BB is solid (that is, no holes).

On their website Praxis suggest you could route the cables on top of the BB, but I don't really see how to install the junction box?

[sharkman]

First of all: it can be done since the first Cannondale Supersix di-2 framesets wheren't any better than a (rather sloppy) diy job done after the frames where finished.
Praxis has nothing to do with the question if a Di2 conversion will work or not (Supersix has a aluminium bb30 sized tube) so you'll have to check if you frame offers enough space to
route the cables around that.

Would I advice drilling? probably not. The Supersix is getting older and seeing one too many framesets with bb shell coming loose I would advice to keep your mechanical groupset and save your money for a di2 specific frameset.

[havana]

Thanks for your reply. Let's assume there is enough space, could you eloborate on the practical side a bit more?

[sharkman]

Internal battery or external?

If internal the first thin I woud do is take a rear break cable and check if it is possible to pass the bbshell (from the seattube).

Drilling would be at least three holes (one top tube, one in seatube for fd and a very large one for the jointbox in the downtube near the bb, and I would have a
problem with that....)

[havana]

Agreed.

This guy drills the large hole for the junction box from the inside of the BB.

http://warracresbikebandit.blogspot.nl/ ... frame.html

Another option would be to make a huge hole in the alloy BB30 shell.

[alanmclean]

Hi Havana
i recently asked on this forum about PraxisBB/shimano clearance and it seems that the very fat sleeve does not leave enough clearance for the wires in some frames.

I am going to find a BB with a narrower sleeve to ensure clearance for wires, you may need the same.

Regards

Alan

[mike]

Used a dermal tool or drill to do the bb. Go slowly as you do not want to drill into your chai stay. Make sure you mark where hole should go first with a sharpie.

[chayanat]

do not drill the bb shell, try wire fishing around bb shell instead.

[havana]

How it is possible to hook up the internal junction box without drilling the shell or making a hole somewhere in that area?

[DeeHubbs]

If the wires will pass above the BB shell freely from the down tube, chain stay and seat post you are good to go.
Fish a line from the down tube hole, RD hole and FD hole through the frame, over the BB shell and run all 3 of these lines through the top of the seat tube, making them long enough to extend from outside the hole to top of the seat post.
Plug all the Di2 cables into the internal junction box and tape the the other ends of Di2 cables to the lines you have run through the frame.
Drop the junction box down the seat tube and pull the lines taped to the Di2 cables back out the through your drilled holes.
I've done this with a few non Di2 frames where I've drilled holes and had a solid BB shell to work around.
It might take a few tries, but with some patience it will work.

[havana]

That makes sense, thx!

[edit]

Another weenie appeared to have already successfully done this modification.

viewtopic.php?f=3&t=130720#p1157402