Shimano resurrects electronic shifting for MTB, but with a caveat


Shimano has brought its XT Di2 groupset back from the grave, but this new and improved electronic shifting is a far cry from the original. For 2022, XT Di2 is an e-MTB-specific drivetrain, which incorporates the motor to allow gear changes without pedalling! There’s also a customisable automatic shifting mode that ensures you’re always in the right gear, and of course, there is a standard manual shifting mode too.

There’s all kinds of battery-powered, motorised wizardry on offer with the new release from Shimano, let’s dive in.

After a long hibernation, Shimano has brought electronic shifting back for mountain bikes. But the new XT Di2 isn’t just a rehash of its predecessor.

What is Shimano launching?

Shimano is launching the XT Di2 groupset in 11 and 12 speed, and two new drive systems, EP801 and EP600.

Each groupset has a shifter, derailleur, bar-mounted controller and a display. Unlike the latest Di2 road components, everything is connected by wires, and taps into the main battery for juice — so there is no charging half a dozen batteries to go out for a ride. The downside here is of course that if the main battery goes flat, you’ll be single-speeding your way home.

We first spotted the new XT Di2 on Mick Hannah’s Yeti e160 at a Big Mountain Enduro event in Missouri, and this wild-looking shifter is what gave it away. Each of the paddles has 15 degrees of adjustment built-in and a tactile click.
There are also a few new options for displays. This one which looks reminiscent of offerings from some of Shimano’s competitors is the mid-tier option, combining the display and controller.

Beyond the different number of cogs at the back, the critical distinction between the 11 and 12-speed XT Di2 is in the weight and durability of the wear components. Linkglide was introduced last year and was essentially designed to be punished and come back for more. With that, it’s a bit heavier, but the new cassette is claimed to shave off 200g on the scale.

Hyperglide+ is the brand’s cassette technology that provides smooth shifting under load through specially cut ramps in the cassette. Linkglide has a version of this, but the HG+ components are lighter in weight.

The Hyperglide tech that allows for smooth shifting under load is what makes the pedal-free gear changes possible.

The EP801 motor is mechanically the same as the current drive system but has updated software to allow for new automatic shifting and tuning features. It still produces 85n max torque and continuous rated power of 250w.

There is also the new EP600 motor, which gains about 300g, but still produces 85nm of torque and 250w, and can do all the same party tricks as its more expensive counterpart. This motor may appear on a few budget-level e-MTBs, but we expect you’ll be seeing a lot more of the EP8 system.

The new EP8 motor is mechanically the same as its predecessor, but the software has been upgraded to allow for the new automatic shifting capabilities.

Let the robots change your gears with Autoshift

Electronic shifting is nothing new for Shimano and with the revival of XT Di2, the Japanese brand has introduced two new shifting technologies, Autoshift and Freeshift.

 

The best way we can describe Shimano’s new Autoshift is by comparing it to the automatic transmission in a car. You press the gas pedal and the gearbox will put itself into the right gear to make it up a hill or cruise along the highway. Autoshift does the same thing as you pedal, it will move the chain up and down the cassette, taking into account things like cadence and rate of acceleration to prevent panic shifting up or down a third of the rear cluster.

Of course, there is a manual override, and if you push the shifter paddle, the derailleur will pop the chain into the next gear.

These shift points can be totally customised in the Shimano e-Tube app. Shimano Australia Brand Manager Toby Shingleton tells Flow in the app you can customise the cadence which triggers a gear change, the shift points, and shift patterns. You’ll also be able to change the shift action speed.

He also tells Flow if you’re riding in manual mode, the groupset will learn your shift patterns, which can be adapted into an automatic setting too.

Just about every aspect of the auto-shifting functionality will be customisable through the E-Tube app.

Pedal-free gear changes with Freeshift

The nifty part about Shimano’s new automatic gear changes is that you don’t need to pedal for the groupset to shift. XT Di2 and the new motor can do this automatically based on your speed in Autoshift, or you can trigger it manually in the Freeshift mode. In both situations, the drive unit will spin the chainring forward, independent of you turning the cranks, just enough to move the chain into a different cog at the back — a bit like a motorised version of the Williams Racing Products CentreHub.

Freeshift allows riders to manually change gears without having to pedal to spin the cassette.

And to clarify, Freeshift is still a manual shifting mode; it simply means you can change gears without pedalling.

So if you overcook a corner and are a bit too heavy on the brakes, you don’t have to pedal through the 11t cog at the back to get into a gear you can work with.

For experienced riders shifting is something that’s become second nature and taking that control away might be a difficult sell, but for new and less confident riders being in the wrong gear is a more stressful conundrum. This new system totally eliminates that.

Why did Shimano do this?

To put it simply, it’s about maximising efficiency and drivetrain life. Let us explain.

Optimum cadence isn’t really something you hear mountain bikers talking about, but on the road, it’s a hot topic of debate. When your pedalling, lower RPMs require more force from your muscles, whereas spinning along at a higher cadence, produces the same amount of power with less energy required — until you get going too fast. Everyone has a slightly different ideal range of efficiency, but a slightly higher (within reason) cadence will always be more efficient than a slow grind.

It’s the same thing with e-MTB motors. There is an ideal cadence range where the motor can maximise its output — Rocky Mountain even goes as far as displaying it on the Jumbotron screen on its latest Dyname drive system. Grinding away up a hill at 60RPM is leaning much heavier on the motor, and commanding more battery output than riding up the same hill at 90RPM.

With the groupset automatically taking some of the strain off the drivetrain components they should last a bit longer, and hopefully, you’ll get a bit more range out of a single charge too.

Autoshift allows the drive system to stay closer to this ideal RPM to give you the most distance/metres climbing for the watt-hours you’re carrying.

The other knock-on benefit is it should also reduce wear and tear on drivetrain components. Shingleton tells Flow that Shimano has noticed a number of clear patterns of wear across cassettes in the e-MTB population, and it’s been a lot of really worn-out 13t cogs.

This is a pretty clear indication that folks aren’t shifting the way they normally would, because the drive unit is giving them that little bit of extra assistance, putting a lot of stress on the drivetrain. With the groupset constantly searching for that ideal cadence, it will spread the load and should help prevent riders from unknowingly grinding their drivetrains into oblivion.

No more slogging up climbs like this in the 13t cog.

When can you get Shimano XT Di2?

These electronic drivetrain components will only be compatible with Shimano’s new EP600 and EP801, so don’t expect to see XT Di2 on an e-MTB spec’d with a Bosch or Fazua motor. With that, the whole system works holistically, so the new XT Di2 is an OEM product for the foreseeable future, meaning it will only be available on new bikes.

We’re not sure who will be the first to wang the new Shimano electronics on an e-MTB, but we’d expect the likes of Canyon, Orbea, YT and Commencal to be quick on the draw for bikes landing in Australia.

XT Di2 will also not be backwards compatible, meaning that if you currently own an EP8-equipped bike. The firmware for Shimano’s EP8 system is stored in the battery, and the current batteries aren’t equipped to handle the latest update.

The battery seems to be the brains of the operation and is in charge of holding onto the firmware, which is why the new XT Di2 isn’t backwards compatible.

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