Shimano Di2 comes to mountain bikes
Caution: May invalidate warranty
Shimano's Dura-Ace Di2 electronic shifting system has been in circulation for a while now. It was inevitable that, at some point, someone would try and adapt it to a mountain bike, and while it may have been done somewhere before, this bike on show at Interbike is the first that we're aware of.
The Di2 mountain bike was the work of Tucson, Arizona bike shop Fairwheel Bikes, in association with carbon custom framebuilder Rue Sports. The frame was designed with internal routing for the rear brake hose and Di2 wiring. Standard Dura-Ace Di2 front and rear mechs shift the chain over a double chainset at the front and a specially-assembled 11-32 10spd cassette at the back.
Bolting on derailleurs is one thing, but nothing resembling a Di2 flat-bar shifter exists. But that's OK, because the shifter is just a pair of buttons - Fairwheel adapted some Shimano Flight Deck controls to take the place of the Dura-Ace items.
The rest of the bike is laden with almost ludicrously exotic parts, including the USE SUB fork, Fibre-Lyte carbon fibre chainrings and brake rotors, Edge Composites rims and bars (with, slightly alarmingly, holes in them through which the brake hoses and Di2 cables run), AX Lightness seatpost and Tune Kong hubs. The whole thing weighs a claimed 18lb.
While it's an interesting project, there's a fair chance that it's also somewhat prophetic. Standard Di2 has been used successfully in cyclocross racing, so it's at least vaguely dirt-compatible. With Shimano XTR due for a refresh soon, we wouldn't bet against the appearance of an electronic incarnation.
I really would rather have a chainring made of cheese than CF. A fruit fly probably has a better life expectancy.
Posted: 24/09/2009 14:00
So Shimano shifting, but SRAM chain? or do Shimano do powerlinks now..? 
Posted: 24/09/2009 14:53
Not have to worry about kit breaking/failing You're clearly not riding like normal humans
Posted: 24/09/2009 16:43
I guess I am not the target audience of these, then? Since it's not for sale it's largely moot  I assume you never ride at night, though.
Posted: 24/09/2009 16:50
I assume you never ride at night, though.
He has a candle on the front of his wooden bike.
Posted: 24/09/2009 19:19
I guess I am not the target audience of these, then? Since it's not for sale it's largely moot I assume you never ride at night, though.
Wear a head torch mike if you cant see what gear you are in
Posted: 24/09/2009 19:44
To be honest I think the carbon disc rotors on that bike are far far far scarier than the chainrings! According to the guy on WW they actually work alright, but squeal. Still, just no! I've had carbon jockey wheels for a couple of years, and they last far longer than the stock SRAM ones, a chainring would probably last alright! There'll be an electronic XTR eventually, but I don't reckon it'll be in this incarnation. Di2 is very cool though!
Posted: 25/09/2009 10:54
Always thought carbon brakes were for very high temp braking, ie F1, MotoGp etc. wouldn't want to be barrelling along grab a handful of brake and just get a squeal and no stop, be like the old pre V brake days 
Posted: 25/09/2009 13:31
Carbon jockey wheels are one thing, but chainrings I believe undergo more force. More force yes, but that wouldn't concern me, you should be able to make CF rings stiffer than alu, and there's far fewer teeth than on jockey wheels so they shouldn't wear that quickly. Wouldn't buy them, don't get me wrong, but I don't think they're the most crazy component on there!
Come to think of it I knew someone using carbon chainrings on a road bike, he was quite a big lad, and never had any problems. I know Fiber Lyte did used to do a ring that couldn't actually be used, it was just for 'show bikes' which seemed really stupid!
Edit: in fact, here it is: I weighed it at 12.5lbs at it's lightest, crazy, and totally unusable!
Posted: 25/09/2009 15:32
Do you remember to put fuel in your car? Or charge your mobile phone? Or eat? He has a point though. Imagine having to 'plug' your bike in overnight for a quick charge. Think of all the posts we have about lights with problems. Electric gears are a recipe for disaster
Posted: 25/09/2009 17:14
He has a point though.
No he doesn't, he's just one of those people who refuse to embrace new stuff until it's about to be made obselete. He's probably still using a PC with Windows 98SE.
Posted: 25/09/2009 19:07
What is this Windows of which you speak?! DOS here. BURN THE HEATHEN! But then again think of the other things that could have made the transition from moto gp like anti dive braking...the only company I know who do that are USE till they stopped making that fork. You're presumably aware that the very bike this thread relates to has a USE SUB on it!?
Posted: 25/09/2009 19:09
ABS for bikes thats what we want as well.
Skids are cool, everyone knows that.
And Bio-Pace is making a comeback, well oval rings are.
Posted: 26/09/2009 18:26
They'd never go for it! Anyway, riding with carbon rims is like ABS, the brakes often shudder horrifically and you won't skid, you won't slow down either, but y'know...
Posted: 28/09/2009 11:20
Don't we already have ABS? I find I can vary the pressure my fingers exert on the levers quickly & easily. Wasn't it Cannondale that used an elctronic damping circuit in their forks years ago? IIRC they gave up due to reliability issues.
Posted: 28/09/2009 12:00
Yeah I only noticed they had that USE fork on when you mentioned it, when i looked at USE's website they mark it as discontinued? not that I could ever have afforded one but if i could i'd like one because it looks different. What about that new cannondale electrical gubbins?
Posted: 28/09/2009 12:13
If they could get rid of all that shimming gubbinry, and make it actually lighter and more user friendly than current systems, it might be worth it. Charging a battery a few times is no hassle surely. Most of us are just weekend warriors, we're not doing LEJOG unsupported etc.
Posted: 28/09/2009 15:01
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