Shimano launched their second generation flagship e-bike motor in the form of the EP8, and we found out how it all came together.
Pete sat down for a chat with Shimano STEPS’ Product Coordinator Pieter d’Haens to find out how they brought the EP8 motor from concept to reality.
What was the inspiration for the EP8 motor?
It started by listening to how E8000 and E7000 was received by the market. E8000 was attention grabbing because it was really powerful and suited punchy, aggressive riding whereas E7000 was less powerful but more controllable, which appealed to different types of riders. With EP8 we were able to combine a more powerful drive unit with greater controllability.
Once you had made that decision, what happens next?
A lot of testing and feedback loops with test riders in Europe, the US and Japan. Once we had a strong baseline we started discussions with OEMs to get their take on it too. All brands have different takes on what E-MTB is and it was important to accommodate them within EP8. This is where the customisation options played a big part.
Who is involved in that process and what do they do?
We have a product team in Europe, the US and Japan who coordinate development, translating market needs and opportunities to R&D requirements. From there our Sales team takes the lead with OEM customers. Finally our marketing teams are responsible for delivering the product campaigns at the recent launch moment.
What did you learn from making the E8000 that you carried over to this motor?
We produced a very high quality product for E8000 and E7000 but we also learnt about market needs for different riding styles (eg controllability through firmware and meeting specific needs by customisation, combined with a highly sensitive torque sensor), and optimising the hardware through better integration (compact size and less internal parts) and a lighter magnesium housing with a bigger heat exchange area to keep the drive unit cooler (and performing at maximum efficiency) for longer. These learnings helped us refine E8000 and create EP8.
How did you settle on 85Nm?
This size drive unit brings the sweet spot of natural riding feeling (weight, centre of gravity), compact drive unit and battery consumption.
How important was it to allow the use of other manufacturer’s batteries?
It’s hard to make a perfect battery for everyone and hard for bike brands to differentiate if they all use the same battery. That’s why we support the use of Simplo, Darfon and BMZ batteries, or allow OEMs to use their own batteries.
How did you achieve the drag reduction on the motor?
This is a combination of the clutch, improved gearing design and the seals of the motor. When the motor is disengaged (e.g. above 25km/h) there are less parts engaged which makes for very smooth (normal bicycle-like) pedalling.
Did retaining the same mounting points affect the overall design?
Of course the mounting points create a slight constraint in terms of shape/volume but at the same time it provides a solid platform for different shape designs and allows manufacturers to make a cleanly-integrated bike.
How many prototypes did you have before you settled on the production motor?
In terms of the complete rideable drive units we tested pretty much from the launch of E7000 in 2017. It wasn’t only the hardware that we had prototype versions of. We also had several versions of prototype firmware too.
Beyond prototypes, what form did your testing take?
Aside from material testing we also did a lot of testing on the natural riding feeling. We use a particular trail in Japan. It’s steep and rooty with step-ups. We take a test team of engineers and product managers from Asia, Europe and America to ride that loop. Then we analyse the rides to create a baseline. Once we have that baseline we send that out to test riders around the world to test in their home conditions. We of course repeat this process until we get it right.
Did you have any outside help for testing?
We test globally with independent riders and with OEMs.
Every trip to Japan to test prototypes is a very cool experience. We typically load up a Toyota High-Ace minivan with bikes and tools then go to the supermarket to stock up on a bunch of weird snacks before we start riding. Snacks played a big part in the development.
Also when made the decision to move from peak power settings of 300% with E8000 to 400% with EP8 we coined the term ‘beast mode’. At first it became an in-joke but then when the controllability aspect began to be refined, ‘beast mode’ really came into its own.
Anyone to thank?
Personally I’d like to thank those who’ve given us detailed product feedback. I’d also like to thank consumers who are really Shimano-minded when it comes to e-bikes and are believing in the qualities and handling that comes from a natural drive unit.