Shimano boosts ebike power with brand-new DU-EP800 motor

More power, lower weights and less friction with app integration and improved software

Shimano’s brand-new electric bike DU-EP800 motor system boosts torque to 85Nm from the older E8000’s 70Nm torque motor, while maintaining the same battery range in Trail mode and increasing it in Eco mode.

The new motor is lighter than the old one, too.

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It weighs a claimed 2.6kg, which is a 300g saving on the previous motor, thanks to its all-new magnesium casing. Shimano’s managed to reduce the volume and therefore the width of the new motor by 10 per cent, too.

Five things you need to know about Shimano’s new DU-EP800 motor

  1. Boosted to 85Nm torque
  2. Reduction in weight to a claimed 2.6kg
  3. Narrower 177mm Q-factor
  4. Claimed 36 per cent decrease in pedalling drag
  5. Same range as the old model in Trail mode, increase in range in Eco mode

Shimano has also tweaked the EP8’s software to produce a “more natural feeling e-mountain bike”. It’s done this by adjusting how the three support modes work and offering user-customisability of those modes via itsE-Tube Ride and E-Tube Project apps.

Shimano DU-EP800 electric bike motor details

More torque, less weight

Shimano EP8 electric mountain bike motor and groupset
The DU-EP800 motor is smaller and lighter than the E8000.

At the centre of Shimano’s new DU-EP800 motor is an increase in maximum torque from 70Nm for the E8000 system to 85Nm, now rivalling Bosch’s recently updated Performance Line CX motor’s output.

At the same time as increasing torque, Shimano’s managed to reduce claimed weight to 2.6kg from 2.9kg for the old E8000 system. This 10 per cent reduction is due to a magnesium drive unit casing and Hollowtech crank spindle, which also claims to boost stiffness.

Shimano claims this gives it a “best-in-class” power to weight ratio.

Reduced friction, bigger range

Shimano EP8 electric mountain bike motor and groupset
The EP8’s internals have been redesigned to reduce weight, improve range and decrease drag.

Battery efficiency, and therefore range, has been improved, too. Shimano’s done this by decreasing pedalling drag from inside the motor by 36 per cent compared to the E8000 system.

Pedal drag is most noticeable when the motor system is turned off – some people have likened pedalling an electric bike without assistance to riding through glue. These sensations should be reduced with the EP8 system.

The reductions have been achieved by altering the motor’s seals, changing its three-stage gear design and using a new one-way clutch, which also gives the motor quicker engagement when the rider starts pedalling and smoother disengagement once the rider stops.

Its range has increased by 20 per cent in Eco mode compared to the E8000 unit and, even though torque has increased overall, battery range in Trail mode remains the same.

Better thermal management, lower volume

Shimano EP8 electric mountain bike motor and groupset
The fins have been changed to improve cooling.

The new magnesium drive unit’s body has better heat management and improved cooling fins compared to the previous system. New EW-SD300 wires also contribute to better heat control thanks to their smaller size. They can also transmit more data, opening up the potential to expand Di2 and other accessory compatibility and functionality.

Improved heat management means the motor can operate at maximum torque for longer without reductions in performance or other reliability issues.

Shimano has also managed to reduce its decibel output, claiming it makes the same amount of noise as the E7000 unit.

Not only has its audible volume been reduced, but its size has been cut by 10 per cent over the E8000. This, Shimano claims, improves ground clearance, makes the motor look sleeker and results in a narrower 177mm Q-factor.

Shimano EP8 electric mountain bike motor and groupset
The Q-factor is now 177mm.

Despite its reduction in size, it uses the same frame mounting pattern as the E8000 and E7000 units, which means bike manufactures can spec any three of those motors on their frames.

It also opens up the possibility of retrospective upgrades to existing E8000 and E7000 owners, however Shimano’s press release doesn’t mention whether this is or isn’t possible.

Upgraded accessories

The new DU-EP800 will have its own XT-level FC-M8150 crank arms that don’t require any axle spacers and are available in 160mm, 165mm, 170mm and 175mm lengths.

A more basic FC-EM600 crank – that looks suspiciously similar to Shimano’s new Deore M6100 crankset – is also available with the same length options as the XT version.

A new DU-EP800-specific CD-EM800 chain device is available and features a mud-shedding design. Thanks to adjustability, it’s compatible with 56.5mm and 53mm chain lines.

There’s also a 12-speed chainring that’s only compatible with 56.5mm chain lines or Super Boost 157mm rear axle bikes without chain devices.

New remotes and displays

Shimano EP8 electric mountain bike motor and groupset
The remote’s buttons are now more concave for easier operation.

The remote control unit has also been updated with more concave buttons, which Shimano says improves operational comfort and control while making it easier to use the buttons.

The new remote – SW-EM800L – is also I-spec compatible which means it should be possible to attach compatible dropper post levers to it, such as Shimano’s SL-MT800-IL.

Shimano EP8 electric mountain bike motor and groupset
The mode selector remote has been redesigned and is now I-spec dropper post lever compatible.

The computer display looks unchanged and works in the same way as the old one. It does now have the option to change between customisable rider profiles (more on that shortly) and can connect to the smartphone-based E-Tube Project app via Bluetooth and compatible third-party bike computers to share gear and battery information.

Bigger batteries

Shimano EP8 electric mountain bike motor and groupset
The EP8 system is compatible with Shimano’s bigger 630Wh batteries.

The new DU-EP800 motor system is compatible with Shimano’s electric mountain bike batteries including its newest and biggest BT-E8016 and BT-E8063 630Wh units or smaller, but faster charging 504Wh BT0E8035-L battery.

Shimano DU-EP800 electric bike motor software and application details

A software re-design

Shimano EP8 electric mountain bike motor and groupset
EP8 connects to smartphones using Bluetooth.

As well as the physical changes to increase torque, Shimano’s re-written its electric mountain bike software to adjust the way the motor’s torque is delivered. It hopes this will make its assistance feel more natural.

The amount of pedalling input torque needed to access assistance has decreased across the modes. Boost mode now only needs 20Nm of rider torque for the full 85Nm of assistance.

Similarly, Trail mode now delivers peak power sooner, requiring only 60Nm of rider input instead of 100Nm for the E8000 series motor and is claimed to be more responsive than before.

Eco mode only delivers 30Nm of maximum torque and that figure is reached using a similar amount of effort to the E8000 system.

Deep mode customisation and application updates

Shimano EP8 electric mountain bike motor and groupset
Power levels are customisable on the E-Tube app.

When connected to the E-Tube Project app, it’s possible to customise the torque levels of the three riding modes between 20 and 85Nm.

Shimano’s introduced rider profiles, too. Assistance levels can be set for different rider profiles which means the bike can be quickly transformed from an endurance, battery-saving bias to an outright power rig.

The on-board display permits profile switching on the fly.

Shimano E-Tube Ride app updates

The E-Tube Ride app – the second Shimano electric bike companion app used to display on-the-hoof information on a smartphone’s screen – has been updated, too.

New features include ride history and live maps plus updates to the user interface. The app will now automatically sync rides with Strava, too.

The navigation feature uses a Mapbox base map that Shimano claims has “street-level detail and high-level path detail in forests and trails,” although information about how the system works is limited and makes us wonder whether Shimano plans to produce a more feature-rich display and onboard computer like Bosch’s Nyon and Kiox systems.

Shimano DU-Ep800 electric bike motor initial ride impressions

Technical editor Tom Marvin has managed to spend some time on the EP8 system ahead of the launch, but hasn’t spent enough time on the bike yet for a full review.

Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
Tom struggled to reach maximum assistance even when well below the 25kph limit.
Russell Burton

I was lucky enough to get hold of the updated Merida eONE-SIXTY ahead of the EP8’s launch, in order to get some ride impressions on the new motor.

While I’ve not had as much time as I’d like on Merida’s enduro-focused electric mountain bike so far, I do have some brief ride impressions of the new motor to share.

First up, it’s worth noting that the accompanying E-Tube Project and Ride apps from Shimano have not been available ahead of launch, so the functionality to adjust the power settings, power delivery and create my own profiles has not been tested yet.


Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
The EP8 is impressively quiet.
Russell Burton

What is immediately noticeable is that the motor is significantly quieter than the E8000 motor that preceded it and those on offer from Bosch. While there is some background motor whine, it’s very quiet overall, something that many riders will appreciate.

Power on and on…

The initial power delivery, in both of the pre-set profiles, is very smooth.

In Eco mode the motor’s support is very subtle and will likely work well for riders looking for that little helping hand on hills and away from traffic lights, rather than those looking for the ‘full’ ebike experience.

Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
The charge port is located above the bottom bracket.
Russell Burton

If the reported range extension is correct, the EP8 could be great for riders on bike tours looking for assistance for their loaded bikes over longer distances.

In both Trail and Boost modes the EP8 provides a very smooth delivery of its power throughout its power band.

At the top end, when the assistance drops off, there’s no cliff-edge in support, so that transfer to fully-human powered riding isn’t quite as demoralising.

While this works well in Trail mode, I did feel that in Boost mode I wanted to be able to exploit the motor’s power all the way to the end of its assistance. I suspect, though, that with the app’s adjustability, this is something that should be able to be programmed in.

Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
My Merida test bike has the integrated Shimano BT-E8036 battery.
Russell Burton

Trail mode is likely where mountain bikers will spend most of their time. Here, the motor’s assistance level seems to easily complement the effort put through the pedals.

This means there’s plenty of torque control when manoeuvring up steep, loose or technical climbs, without much in the way of uncontrolled wheel spin.

Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
There’s more ground clearance because the motor’s size has been reduced.
Russell Burton

While the previous generation E8000 motor was very well mannered, the EP8 feels just that little more refined in this respect.

As mentioned, I would like to spend more time on the Merida eONE-SIXTY to get a better grip of both the bike and the motor.

Some niggles

However, if I was to draw any early criticisms, it would be that I struggled to get the motor to provide its full level of assistance (as indicated by the sliding scale on the motor’s display unit) even when tackling steep climbs and putting in as much manual effort as I could.

Merida eOne-Sixty electric mountain bike with Shimano DU-EP800 motor
The motor’s power cut-off too quickly.
Russell Burton

This may well be a result of the power delivery tailing off to give a smoother transition to non-powered riding, but on steep pitches I was so far off the 25kph limit that, really, I’d like the full 85Nm of power to be easily delivered in this situation.

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As ever, more time, and access to the app, may negate this initial criticism.