After having had a lot of fun building my Di2 road bike (viewtopic.php?f=10&t=79891
), next comes the Di2 TT bike.
Velocite's TT frame still being under development I am using an open source frame for this year, as used by Ritte, Museeuw, Planet X, etc. It's actually a design by Lewis Mathiske, who also (more recently) designed the Velocite Helios Aero.
Building a new Di2 bike it wasn't enough to just put the battery inside the seat tube anymore. Been there, done that, with the help of coloclimbers and others. A friend of mine and I didn't like the Shimano Di2 TT levers and bar end shifters, so we decided to go our own way. The "buttons of choice" at the moment seem to be the Cateye remote buttons that were made for a Cateye wireless computer: small, low profile, and water proof.
The tricky part is how to place these buttons on bar end shifters. Most normal bar end shifters are not very well suited to this, because you need to stick the buttons on them, which makes them prone to coming off. So after much looking around, we found 3T aero bar levers, which have one important advantage: they are clamped onto the bar by sliding them on. The idea was to drill holes in the levers to make space for the buttons. Actually this is a pretty tough job, considering there is not much material to play around with and the things are round. Luckily, a friend of a friend works as the house mechanic in a big company nearby, and he is a bike head. He did a pretty stellar job:
When I checked my Syntace bar, I found that they had kindly used a non-standard diameter! It was not possible to slide the levers over the bar ends. So the same friend worked some serious magic on the lathe and came up with a very sweet way to attach the buttons and lever to the bar:
The setup actually works out about 20g lighter than the 120g that are given for the Shimano bar end shifters (per pair):
That should save me at least 0.002s on an Ironman!! ;-P
To be continued...