Pictures in the Club photos album

Dura-Ace Di2 – shifting at the speed of light

Electronic shifting might seem to be more complicated just for the
sake of being, but the technology does offer performance advantages
practically unattainable with mechanical systems. Our experience with
earlier prototypes indicates shift button throws are remarkably short
and derailleur movements are much faster than spring-loaded versions.

The Dura-Ace Di2 group will not only shift faster than the current
Dura-Ace group but our information suggests that it's also over 100g
lighter, even with the battery pack. We'll see how close to reality
those figures are come production. Some of the weight savings comes
from the use of alternative materials, as on the mechanical version,
but we suspect the bulk of the loss comes from the omission of
mechanical hardware.

Neat features include optional remote shift buttons for time trial
setups; a `crash position' that helps shield the rear derailleur from
damage during a fall; and an auto-trimming front derailleur. We're not
sure why the latter is necessary if Shimano is touting a `trim-free'
front derailleur on the mechanical version.

Reliability is always the big concern with electronic shifting.
Mavic's two attempts at the idea, Mektronic and Zap, suffered from
disastrous reliability and that colours everyone's attitude to
electronic gear controls. However, it does look like Shimano has done
its homework with D12. We've been seeing these components in the field
for several years now and it seems highly unlikely that Shimano would
release this sort of technology without thoroughly working out the
bugs. Reliability is also likely to be Shimano's primary reason for
using a wired set-up instead of a wireless one.

But why bother with electronic at all, you ask? We posed the question
to Walton a while back regarding electronic groups in general and it
isn't difficult to transfer his response to a performance-oriented system.

"The idea of operating a drivetrain electronically and using
electrical actuation is one that Shimano has been engaged in for many
years," he said. "Take for example our Nexus Auto-D internal
four-speed system. The idea was to create a drivetrain that had the
least amount of potential issues necessitating adjustment and
versatile, yet simple operation.

"Friction and cable contamination are removed by using electrical
signals; precision is ensured by precise servo motor movement;
adjustment and accuracy are monitored with each shift; the user
interface can be operated via a simple push of a button or using an
automatic mode."

An automatic mode? Um, okay. Battery life is expected to be in the
range of months for typical users although there's no word yet on what
happens if it dies out on the road.
"It will make everyone else's road groups look like toys"

That was the comment we heard from one industry insider (who doesn't
work at Shimano) and it'll be interesting to see if that holds true.
We'll reserve judgment until we have access to a proper test session
on production gear but one thing is certain: the market is heating up
yet again and we all stand to gain.