Di2 - A few questions to owners

[SkinnyBoy]

I'm considering Di2 Ultegra for my current build and have a few questions.

For those who have retrofitted it, Internal or External wiring?

If internal, did you drill your frame and use the grommets that shimano supply separately or did you fabricate something?

The battery, anyone using the new internal BTR2 unit that goes inside the frame? How long is the standard battery wiring if i wanted to fit the standard battery in my aero seatpost (its like an aircraft wing haha)

Merlin are doing a great price on it at the moment and the man maths calculating machine said yes why not!

[LotusMartin]

Here's the post on my conversion : http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I had a custom internal loom made by a guy out in California, including an internal battery in the seat post. Its neat - only change I would make in hindsight is a longer/more robust cable to the seatpost battery so there is less danger when I travel with my bike and having to remove the seatpost all the time.

I drilled my own frame - with the right tools its a piece of cake. I bought a dremel and a Dremel 570 Grout Removal Bit 3.2mm (a 562 would also do), Also useful was the right angle attachment. There is a bit of a technique, if you're nearby I'll happily do it for you.

Also - set up the rear derailleur without the chain on - lining up the cogs exactly - this was much more successful than using the auto alignment function.

You won't regret it - Di2 absolutely rocks, I'll never go back to mechanical.

[SkinnyBoy]

Great stuff! I did a bit of look on Google and it came up with the Calfee DI2 battery which looks very similar to your setup.

I have a few burrs and a couple look exactly like that grout bit you used. I have a variable speed Snap On die grinder that drills perfect holes like this which I use in work on various stuff.

Having had a play with a bike with Di2 I was more than impressed, mechanical sucks compared to it.

Thanks for the info and writeup

[LotusMartin]

The drilling technique was to drill a 3.2mm pilot hole at slow speed, take it easy as the carbon resin melts a bit. Then use the grout removal bit at a much higher speed to gradually open up the hole and shape it into an oval. I highly recommend you get one of those exact dremel bits - they left a really clean finish. Then seal the edge of the carbon hole with either some 2 part epoxy resin or something like Araldite. This will stop water ingress and carbon delamination.

Take your time and it will be fine. I was lucky as I had a few practice goes when I picked up my set in LA.

Oh and buy an extra junction box then you can charge the battery by plugging it into the rear derailleur cable

[SkinnyBoy]

LotusMartin said:

Oh and buy an extra junction box then you can charge the battery by plugging it into the rear derailleur cable

how does that work?

[LotusMartin]

The charger (well the one I got) plugs into one of the spare ports on the shifters, if you buy another junction box (like - www.petracycles.co.uk/shimano-ultegra-smjc41-6770-... You can just unplug the cable from the rear derailleur and plug the charger in there. Much more convenient. Not that you need to charge it very often.

I've just had a search and I can't fine the charger I'm using anywhere, but I'll take a photo when I get my bike back from the LBS.

[SkinnyBoy]

Cheers for that it's a great help. I'm going to have to reconfigure my internal routing that's on the frame at the moment as I hate the way the front cable goes straight into the top tube vertically, I love the way Di2 cleans up the routing.