Review: Shimano's STEPS EP8 Motor is Great, But Not Perfect - Pinkbike (2024)

After our quick first ride article, I was able to take more time to test out Shimano's new EP8 motor. Most of the ride time was spent aboard Merida's eONE-SIXTY 8000, with a few rides on Propain's Ekano. Many of the results were similar to what I wrote about in the First Ride article, although some significant details having come to light during proper testing.

EP8 Details

A three-stage gearing system with six gears is optimized for the high RPMs of the motor and utilizes efficient reduction gears to allow for the motor's compact design. A one-way clutch delivers smooth engagement while reducing drag for a natural riding feel. Said drag has been reduced by 36 percent over the old motor, with greatly minimized driving noise. Heat management has been optimized by introducing heat-conducting magnesium materials, an increased surface area in the case and even a refined heat management algorithm. Under high heat buildup in the past, the old motor could reduce its output down to 40Nm; the EP8 will go down to 70Nm at the most at a much later point.

The new SC-EM800 display looks very similar to the known SC-E8000, but features a more capable chipset, expanded compatibility with third party computers thanks to ANT, and the ability to select two different custom ride profiles. New wires (EW-SD300) can transmit data faster due to increased bandwidth and make the system future-proof for new features. It can also communicate with other devices via Bluetooth LE.

With most manufacturers having shied away from the trigger-style remote that was available for the E8000 in the past due to conflicting with most dropper post remotes, a new handlebar-mounted assist switch (SW-EM800), similar to the 7000-series version but with slightly larger buttons and greater tactile feedback is now available.

The SC-E7000 black-and-white display and SW-E7000-L handlebar remote will still be compatible with the EP8, although only with adapters connecting to the thinner cables.

A 160mm crank arm option has been added to the 165, 170 and 175mm range, with the Q-factor remaining at a narrow 177mm.

Chainrings and spider are common with other STEPS systems and support chain lines of 50, 53, and 56.5mm for 9, 10, 11, and 12 speeds. Depending on the model, chainrings with 34, 36 and 38 teeth are available. A new chain guide, the Shimano STEPS Chain Device (CD-EM800) is compatible with 53 and 56.5mm chain lines for 34- to 38-teeth chainrings and mounts directly to the motor.

Even though Shimano offers external down tube mounted batteries with 418, 504 and 630Wh, these days you'll mostly see the internal batteries on higher-end mountain bikes. A 504 and 630Wh integrated option is available, as well as an older bulkier square style of integrated battery with 504Wh. Since their system is open to third-party battery suppliers it’s still not uncommon to find some Shimano-equipped e-bikes with other battery packs as well.

Their in-tube batteries are designed to either be charged inside the bike if a manufacturer adds a charging port to the frame, or directly at the battery when removed. However, an extra adapter - which usually comes with the charger - needs to be attached to the battery for that to work. Something to remember if you're going on a trip where the bike can't be stored inside the accommodation near an outlet. Claimed weight for the 630Wh integrated BT-E8036 battery is 3,700g, an increase of 650g over the BT-E8020 integrated 504Wh battery.

For the launch of the EP8, Shimano has completely revamped their assist algorithm for all of their support modes to organically match the rider’s efforts and deliver the right power at the right time. The new algorithm constantly calculates the ideal assist ratio depending on the situation, compared to the older way of calculating a single assist ratio for each riding mode.

Due to the rather low weight and smallish form factor, expect the EP8 to show up on the newer breed of e-bikes with smaller batteries and lower weight, like Rotwild's R.X375 or R.E375 line with custom 375Wh batteries.

App

The E-Tube Project app, available for iOS and Android, that can communicate with all of Shimano's electronic equipment (including Di2), got a complete overhaul. Most of Shimano's displays can communicate with your smartphone via Bluetooth, and the SC-EM800 is one of them.

There are two profiles that can be altered, and either one of those profiles can be selected from the display during your ride. Within each profile, each ride mode is now customizable in three categories - assist character (level of rider support), max torque (the maximum torque the motor can provide) and assist start (the sensitivity of the motor reacting to the initial stroke of the pedal). Assist character and max torque can be adjusted in ten steps, assist start in five. Maximum torque can be set between 25Nm and 85Nm. The E-Tube Project app can also provide maintenance reminders.

A second standalone app, Shimano's E-Tube Ride app, receives all the basic info from the display at your smartphone. You're able to rearrange multiple screens with the information you want to see. Also, you can record your ride and send that recording to Strava afterwards.

Setup Notes

While I applaud Shimano for not having to deal with the initialization of the torque sensor before every ride anymore, effectively eliminating the chance of causing error W013 to pop up and shutting down the bike in case it would sense any load on the cranks, their safety protocols are a bit annoying.

Every time you start your bike, the ride mode is set to off. I'm not sure if they are afraid of people not remembering that they are sitting on an e-bike and shooting off into the trees, but basically every other motor manufacturer lets the system start in whatever ride mode it was sitting in before it was shut off - without a problem, I should add. I'd say it's fine that the protocols are in place initially, just give the end user an option to switch the safety protocols off in a sub-menu on the display. It might not be a big deal to a lot of people, but I know some that are so annoyed by this feature alone that they wouldn't pick Shimano over a competitor.

In order to connect the E-Tube Project app to your bike the power of the bike needs to be switched on, but its ride mode has to remain in the off position. On one test bike, I was able to make a connection to the bike after about the third try, and on one it wasn't possible at all, giving me an error I couldn't find anything out about when researching it.

I connected my Garmin 830 to the bike via ANT and that ended up being a surprisingly simple task, also quickly finding the bike again when both units were switched off after a ride and then on again. However, when you connect the E-Tube Ride app during a ride at the same time it disconnects your Garmin, so running both at the same time does not seem to be an option. On a few occasions when switching the phone into standby the connection was lost and it had to be reconnected again. I am not sure if recording the ride would have been disrupted as well by that, but it looks like the GPS tracking works independently from the rest of the data.

Display Hits & Misses

Unquestionably, Shimano has the cleanest and sleekest display integration on the market. But in my opinion, Shimano has dropped the ball by not upgrading the display with percentage numbers for the battery level. It feels like staring at a Nokia 3310 cell phone when everyone else is running around with an iPhone 11, or soon 12. With only five bars of battery charge showing, there's no way to tell if your bike is still running on 40 percent or 21 percent unless saw exactly when a bar dropped from two fifths of the reading to one fifth.

According to Shimano, "The new display does indeed continue using the five bars of battery charge. The goal was to keep the same sleek design as the E8000 and that limited us to the five bars.

However, computers like Garmin do have the ability to show battery level as a percentage number. Also, the new E-TUBE app can do the same thing. While we don’t expect people to ride with their phone on their handlebars when mountain biking, the battery level can easily be checked in common situations like when a group of riders stops on the trail to compare battery levels and make sure everyone can finish the ride.

Or, if you are riding and have three bars left but aren’t sure how long ago it dropped from four, you can pull out your phone for more precise battery level information."

First of all, I do not want to fiddle with my phone when I'm out riding my bike, apart from the fact that riders with other systems can just look at their display and get the proper info, so it's not like the whole group has to stop in order to figure out if they can do another loop or not. As for reading the battery level off their E-Tube app, all it showed me was, surprise, a battery symbol with five bars. I can only hope that the app will see an update one day with the option of percentages. Also, you'd have to connect your phone with your bike being set to the off mode to begin with. With Bluetooth, the success rate or time needed for building that connection can sometimes vary.

As far as real estate on their display goes, just printing the percentage number instead of the battery symbol would have given me more than enough room to do that, or adding the number as a sub-menu, would have at least been another option. Actually, if you really look at it, Shimano is quite good at wasting real estate on the SC-EM800 display, and I could think of quite a few options of how to make more important info fit the main screen of the small display. They could have also just split the five bars into ten as well, at least you could have doubled the information that way.

The only real viable solution for an exact percentage reading is getting the readout with a Garmin or similar computer, but that would require you to buy a computer if you don't already own one and ride with two displays, which would totally negate Shimano's idea of a sleek design.

Other annoying things to consider with Shimano's display is the fact that when looking at range or other sub-menu information it automatically jumps back to its initial screen after about a minute or so. The only item it doesn't jump back from is cadence. Also, their sub-menu order is somewhat dated as well. Why in the world the ODO is situated before remaining range is beyond me. Usually, I wouldn't care if the display jumped back on its own, but since I have to hit the small button repeatedly when my battery charge becomes critical on some rides, the more often you have to hit the button every few minutes the more you'd wish for a different setup. Again, Shimano can set it up the way they want, but please give the end user the option to change that display's behavior.

Apart from all of that, Shimano still doesn't give you information about rider input, which isn't necessarily vital, but a nice info to know about in certain situations or for people that like to use their e-bike as a training tool.

Being able to customize ride modes with their E-Tube app in multiple ways is simply awesome. Similar to Specialized's approach, you can tweak the bike to your liking in multiple ways. Also, it enables companies to preset their two profiles to specific ideas of what their bike is intended for.

Especially at lower cadences, the new motor can handle loads much better and propel you forward without a drop off in power, even in steep terrain. Speaking of steep terrain, it's much easier to get the bike going from a standstill in those kinds of situation, as the power added to the pedals smoothly transfers to the rear wheel. It's rather easy to control rider input and power delivery in general, even in Boost mode, where the power output used to be much harder to control in the past.

In direct comparison to Bosch's Performance Line XC Gen 4 or Specialized's 2.1 (Brose Drive S Mag), both those competitors still offer slightly more punch in their highest ride modes, although the difference is not nearly as big as it was compared to the E8000.

After having played around with each of the settings in the E-Tube Project app, I found Shimano's new setup for the Trail mode a great choice for various riding conditions. I used to avoid using the underpowered Trail mode on the previous version, but utilizing the full 85Nm of maximum torque when needed with a much more powerful base setup means that mode will see a lot more use. If you enjoyed it the way it was, you can simply detune the setup.

The only thing that could possibly be improved upon, with Shimano's factory setup for Profile 1 already being set to the highest setting for all options in Boost mode, would be to actually increase the possible output for all those variables as an option for riders looking for an even punchier feel from the motor. Even if maximum torque was carved into stone, higher options for assist character and assist start might elevate the EP8's power output to level equal to Bosch's Gen 4 or Brose's Drive S Mag.

Being able to change between two motor setup profiles from your display is a useful feature. You can even do so during your ride, although you have to stop to allow the system to switch over. It mainly allows you to create a more aggressive setup for your after-work-loop and one for those epic day's ride where you want to make sure that you make it out of the woods with energy to spare.

With the option to custom-tune those two profiles further, Shimano's E-Tube app is a smart tool for anyone interested in tweaking their motor's behavior to their ideas. In the end, many riders only predominantly use the Eco and Trail mode, so them detuning the Boost mode probably makes a lot of sense. Since Profile 2 of the stock setup does reduce the overall power and power transfer from all modes, they might be happier just by selecting that option.

Also, having these options allows bike manufacturers to create profiles according to what they think matches their bike's character best, or helps them to introduce new concepts with smaller batteries and lighter overall weight to the market, like what Rotwild is doing.

There is still a slight initial transition every time you start spinning the cranks from standstill and when abruptly stopping to pedal, although it's much less than before. It's a subtle double-clicking resistance that can slightly be felt through the pedals and, if you pay attention, even be heard. It really doesn’t affect the ride quality though, and at some point you just forget that it's even there. Plus, it's not that often that you start from standstill during a ride to begin with. Having said all that, I have found one situation where it bothered me slightly, which was during track stands where the constant cutting in and out make balancing a bit more undefined. Since doing track stands on your e-bike won't be a high priority, I'd say it's not an issue.

One of the greatest strengths of the EP8 is how quiet it is under load, even in Boost mode. Only at really high cadences does the motor noise increases slightly, but even then it stays composed. It's more a hum than a whine, and easy to forget about in seconds, especially in the flats or over rolling terrain. The motor is probably the quietest full-size motor on the market today, at least as long as you are not coasting over uneven terrain.

Motor Rattle

I remember dealing with a rattling noise when riding the EP8-equipped bike for the first ride article, but I was too focused on other impressions to dig deeper. On my next ride after the article was published it became clear when rolling down nothing more than a short fire road transition that the distinct noise was coming from the motor.

The noise is best described as a metallic rattle, similar to chain slap on bikes without chainstay protector. It's also very similar to Bosch's Gen 4 motor rattling, but maybe even at a higher frequency. Once you hear it, you cannot unhear it and it's simply annoying.

Here is Shimano's official statement to the questions of what the reason for the rattling noise is, and if they are working on a fix:

The new EP8 drive unit provides incredibly quiet assistance under pedal load. However, when coasting on rough terrain the unloaded system can exhibit a normal clicking sound that may be detectable to the rider. The clicking sound has no effect on the function or durability of the drive unit. EP8 delivers significant performance improvements with higher peak torque, greater range, lower driving noise, better heat resistance, and reduced drag. These metrics are balanced with other important priorities such as durability and overall ride experience, with the best combination of key benefits ultimately resulting in a minor noise being detectable under specific riding conditions. Shimano works diligently to deliver the best overall product experience and will continue to listen to rider feedback as we strive for continual improvement of our productline. — Shimano

In my mind, the noise generated by the motor when coasting should have been deemed as unacceptable (I feel the same way about Bosch's approach).

From having tested two EP8's, one embedded in a carbon and one in an aluminum front triangle, the pitch and intensity of the noise might change slightly from frame to frame (the same as we've seen with Bosch), and of course I cannot speak for every motor that will be equipped, but colleagues have confirmed that they've experienced the same issue. While we didn't get a clear explanation on what is happening inside the motor, I assume it's a similar cause as found with Bosch, where the gears are moved slightly by the bike kinematic's chain pull or vibrations caused by uneven ground when there is no load on the motor. So while it might not cause any technical issues, it's still annoying

In terms of battery management, the moment the display drops down to a single bar of charge left, or even before that, the system becomes as unpredictable as ever. With a theoretical rest charge of 20% on one of my rides in Trail mode and 12km left on the range display, the display jumped down to half of that within a few hundred meters and then continued to skip numbers from five to three and then to one when limping home in Eco mode.

Using the Garmin option to see the remaining battery charge in percent gives you a much better idea of your remaining energy level, although beyond about the last quarter or even third of charge left the battery seems to drain at a highly progressive rate. That's not necessarily uncommon for batteries of any type, but the difference between the first half of the charge to the second is significant.

At the ten-percent mark your Garmin gives you a warning, with the bike finally shutting down shortly after it shows you a remaining charge of six percent. I assume the cutoff happens at five percent, which would correlate with the required by law rest charge necessary to still power lights or other equipment even after the motor shuts down.

At least now the bike can still be started once turned off below a remaining range of 12km, an improvement over the E8000. Even at only one kilometer of range left on your display you can switch the bike off and on at your leisure until the battery fully drains.

Test Lap
Boost mode: 23.1km/1.250m @75kg tested (27.13km/1,436m @55kg tested)

Doing my lap test - which still is anything other than scientific, with many factors like rider input, components and bike weight not being standardized - it's intended to give a vague idea of how one motor system compares to the other on the same lap.

Since my low weight of 55kg always caused room for speculation on what the range for a heavier rider might look like, I ended up packing an extra 20kg of weights into my backpack on a second loop. By trying to find a pedal input that kept my lap times close to what they were with my regular setup I assumed that this would be the approach you'd want to see when riding with your buddies at the same speed.

Surprisingly, and contrary to my assumption from the motor comparison story from a few months ago, the difference wasn't as high as expected, only coming to about 15%, rather than the estimated 25%. Of course, that might be different with other motor systems and maybe I'll repeat those laps with the other motors down the road out of sheer curiosity, even if riding with the extra weight is about as fun as poking a hot needle into my eyeball. Not that I've ever tried that.

Compared to Bosch's Performance CX Gen 4 and Specialized's 2.1 (Brose) systems in my non-scientific reach test, the overall range of Shimano's EP8 was a bit disappointing. Especially compared to Bosch, with the comparable 625Wh battery size, Shimano only managed to climb about 350 meters less in altitude. Arguably, that Bosch motor was tested with the older 75Nm setup, but I heavily doubt that raising the maximum torque an extra 10Nm after the summer update would shrink its range down to that number. Theoretically, jumping between Trail and Eco mode almost doubles the range of the EP8, but unless I was willing to ride the same lap in both those modes as well (I am not), it's hard to tell if the system really follows the display's prediction.

Less drag over the cutoff limit is nice to have, but it wasn't bad before to begin with. Pedaling in the flats beyond the 25km/h (or 20mph in North America) limit with an e-bike however will never be amusing, so it really only comes in handy going down a hill. When the bike does come to a stop, Shimano's walk assist mode is finally easy to access and now pushes the bike forward efficiently and powerfully, no matter what gear you're in. Simply push down on the lower remote button and hold the upper button afterwards.

Pinkbike's Take

With the new EP8, Shimano managed to close the gap to its biggest competitors. It even surpasses them in terms of noise (very quiet under load) and weight. Display integration is still the best on the market, even if it only shows five bars of battery level and could easily integrate some more user-friendly features. Their new ride algorithms make the EP8 one of the most natural feeling motors out there, with plenty of power to propel the bike over obstacles, even if Bosch and Brose are still a bit punchier and deliver slightly more power. The biggest downfall, however, is the motor's annoying rattling noise when coasting over obstacles. Is the rattling during coasting enough to shy away from getting a bike with Shimano EP8 motor at the end of the day? Probably not, as it performs better in any other segment than its predecessor and the EP8's biggest competitor Bosch is basically doing the same. Overall, the EP8 is a great motor, but not a flawlessone. — RalfHauser

Posted In:
eMTB Reviews and Tech Reviews Shimano Shimano Ep8

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