Rumours about a new Shimano motor have been circulating for months. Now it’s finally released, the new Shimano EP8. Due to the pandemic, there was no press release event. But we were lucky enough to get hold of a motor and to communicate briefly with a guy at Shimano Public Relations. I’ll let him introduce the motor.
Shimano: “The new EP8 drive unit is capable of pumping out 85Nm of torque to conquer the toughest trails and steepest climbs. This 21% increase in power over its SHIMANO STEPS E8000 predecessor comes along with a 300g weight decrease to 2.6kg (10% reduction) thanks to a new magnesium drive unit casing and optimization of the internal components. This low weight and high peak power make it one of the best-in-class drive units in terms of power-to-weight.”
Silent and efficient
Shimano also claim the new motor is more battery efficient. The old E8000 had little resistance when pedaling without assistance. Thanks to improved seals and changes to the motor internals, the EP8 has 36% less resistance. Together with the friction-reduction is an improved clutch mechanism which provides a smoother cut-off when pedaling above 25km/h. Increased motor power can lead to increased noise. But not in this case. Shimano says the EP8 is less noisy than the E8000. Noise level is on par with the E7000.
The magnesium motor casing and the redesigned internals has improved cooling. And that’s important. An ebike motor is legally allowed to deliver more than 250W for a limited time. When it reaches “thermal equilibrium” it cannot exceed 250W. Thermal equilibrium is where the temperature stabilizes. By improving cooling, it takes more time before the motor reaches thermal equilibrium. This means it can deliver high power for a longer period before power is reduced to 250W.
As on the E8000, the crank axle bearings are not replaceable. Shimano says these are high grade sealed bearings that doesn’t need replacing. They also talk a bit about anti-tuning and anti-tampering. Any attempts to alter or trick the cut-off speed will be stored in the motor. The dealers will see this flag in their software. If this happens, the warranty will be void and they cannot service the motor.
Shimano is releasing a new E-Tube app. The app will be available when the motor is launched, so we haven’t had the chance to test it yet. But we’re happy to see it offers more tweaking options. Now there are two user profiles that can easily be switched between using the button on the new EM800 display. This display looks similar to the old E8000 display. But the EM800 has got Bluetooth support and connecting it to the app seems easier.
So, how does the EP8 ride?
We tested a pre-production motor. It may be different to the final production motor. But this is the fourth time we test a pre-production motor. In our experience, the motor characteristics is pretty much the same on the production motors. But there could be changes to the production motors, either immediately or through future software updates.
There is a video at the bottom of the article. It shows how the testing has been done and it illustrates what we’re trying to describe below.
Can be quick to activate
After the motor has activated, it immediately provides a lot of power. And it does so very well. When activating, older motors usually provides a surge of power that can last for tenths of a second. This makes it difficult controlling the bike in technical terrain. This is most noticeable at high motor power. Despite immediately offering a lot of power, it’s easy controlling the EP8. It instantly responds to changes in pedaling force and it doesn’t shove you away unless that’s what you want. Both the old E8000 and the Bosch Performance CX gen4 can be a bit pushy when the motor activates.
We could ride the EP8 at maximum motor power, and it was easy to control in all sorts of terrain. We rode places where we had to reduce motor power on the E8000 to stay in control. But we eventually got into trouble with the EP8 too. On day two of testing, the trails were wet. And we had more assistance than we could deal with when trying to ride the slippery rocks in our regular test climb. By dropping assistance to Trail mode, control was improved. Things got easier and less hectic.
We did several tests of motor power, and we recommend you watch the video for more details and data. The EP8 amplifies rider input significantly more than the E8000. We got as much as 400% for the EP8. The new motor feels more powerful when the cadence drops. We never really missed more power than what the E8000 can deliver. But when the EP8 dishes out more power in a more controlled manner, it’s easy appreciating the power increase.
But it’s not all improvements
Shimano claim the noise level is improved on the EP8. And they’re sort of right. It’s considerably less noisy than the E8000 and Performance CX when pedaling. But it’s only when the motor is running. When coasting over uneven surfaces there is a clicking or rattling noise. It’s only there when we’re not pedaling. The Bosch motor has the same noise, and they’ve been criticized for it. Our impression is the EP8 noise is a bit less constant and intrusive compared to the Performance CX.
Pleasant at higher speeds
The motor will assist at full power up to just over 25 kph. It continues to assist at reduced power up to just under 26 kph. There is still a little assistance before it cuts entirely at 26,3 kph. This seems a bit more liberal than the E8000. The transition feels silky smooth when we pedal past the cut-off speed. Both the E8000 and the Performance CX was fine pedaling without assistance. The EP8 is no worse. Actually, it could be a tad better. But it’s difficult to say. We couldn’t find a reliable way of measuring it.
It was almost a revolution when Shimano introduced the E8000. We won’t use that big words about the EP8. It’s better in most aspects. But not everyone will accept the rattling noise while descending. We really appreciate how easy it is controlling the motor, and how little noise there is while pedaling. And we’re happy about the surprisingly big weight reduction. We like the EP8 a lot, it’s currently our preferred motor.