Innovation has been constant
in the relatively short history of mountain biking.
In the last few years, we've seen
the emergence of electronic gears.
But let's take a look at the Shimano Di2
to see what it's all about.
(fast-paced electronic music)
So what are the main differences
between your average mechanical gears
and these electronic gears?
Well, coming to the rear mech from the bottom up
it looks quite normal. You've got jockey wheels in the cage,
you've got that shadow chain tensioner
with the switch on and off there.
Spring tension the rear mech is.
But the biggest difference here is the motor
on the back of the mech.
So this is normally where your gear cable will come in.
You've got a motor here and that wire coming out.
Same on the front mech. Looks kind of normal, the cage,
but you've got that motor sat on top.
So each wire from the mechs, the front and rear mechs,
runs into a junction box that's inside my frame.
One cable length comes up and goes
to this LCD display up on my handlebars.
This gives me a bit of information about my gears,
what gear I'm in, what shift mode I'm in,
more about that later,
and actually how much battery I've got left.
Because of course, you need a battery to run these gears.
There's a few different solutions
for where to mount your battery.
It can go externally, on things like the bottle cage.
I've got a really neat solution on this bike,
it's sat internally inside my forks tube,
just under this plastic cap.
So this is the small lithium-ion battery
that is actually really surprisingly light.
Obviously, one of the disadvantages
of running electronic gears is you have to
remember to charge your battery.
However, they do give up to 1000 miles of battery life,
so you shouldn't have to worry about that too much.
The way you charge that,
you don't have to whip it out actually,
you just plug it in to the side of that display.
So, pretty simple when you do need to do the job.
(fast-paced electronic music)
another neat little touch is I'm using these
Pro handlebars and stem which is a subsidiary of Shimano,
and the wires run internally.
So they pop out in front of the stem,
and they run internally up the final piece of the jigsaw,
which is this shifter up on the bars.
So the shifter is really customizable.
You've got small allen keys on the back
to move these paddles around,
but also if you plug your PC into the system
you can choose what the shifter does,
so how fast you want the shifts,
I got it set up really fast.
However that does mean you could miss shifts
if you maybe hold your thumb on too long,
but I do like that fast shifting.
Also, you can set what paddle does what.
For the moment, I've got the lower paddle
changing to the higher gears,
and then the top one going to lower gears.
You can swap that around if you wish.
And also you can change how many gears
that paddle shifts at a time.
You may have noticed that
I've got a front mech and a rear mech,
but only one shifter on the bar.
That's because I'm taking advantage
of something called synchro-shift.
You can run another shifter if you wish,
but I think the synchro-shift is a really clever system.
So what that does, is you just use
your right thumb to do everything.
And this system will find the next gear for you.
So that might not be just a shift on the rear,
it might actually be a shift on the front as well.
So it takes the brain work out of it,
and it'll just find that next ratio.
That's pre-programmed in, there's a couple
of different programmes in there already that you can choose,
but also that is fully customizable
again by plugging in your PC.
This Shimano Di2 system is available for
one-by, two-by, and three-by systems at the moment.
You can see, I've got two chain links up front.
Right, that's enough about the tech,
let's take it for a spin.
(fast-paced electronic music)
You often have to shift under quite heavy loads
when you're mountain biking so
putting a lot of power through the pedals.
That's one thing I've definitely noticed
with the electronic gears, they shift so quick
that you don't have to ease off quite so much.
Another nice little touch is the display
gives me a little beep to tell me
if the next shift is going to move on the front mech.
And that's when you probably do need to ease off
a little bit more.
So what are the advantages over the mechanical shifting?
Well, the gear shifts are really fast
and really accurate.
I guess the biggest advantage is the gear cable
is never going to wear out,
so if you often have to change your gear cables,
because you get friction in them,
that does not happen with this.
I guess the payoff is, you have to
charge the battery occasionally.
It's quite a luxury having this display as well.
I do like having that beep, when the front mech is shifting,
but also, there's another beep that tells me
when I'm in the extreme of the gears,
so the highest gear or the lowest gear.
It's a bit like, carbon fibre mountain bikes,
you don't need one, but it's actually
a very nice thing to have.
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