Shimano EP8 has sufficient power, a refined engagement, improved software and a really quiet operation, all wrapped up in a lightweight, compact package.

>>> Guide to the best electric mountain bikes

Shimano EP8 motor need to know

• Torque rises to 85Nm to compete with Bosch Performance Line CX (85Nm) and Brose (90Nm)
• 10 per cent smaller in volume compared to the old Shimano STEPS E8000 means more ground clearance
• At 2.6kg the motor is 300g lighter than the E8000 unit and one of the lightest on the market
• Shimano has reduced the noise output of the motor, making it one of the quietest on the market
• Better cooling means more power for longer in hot weather
• New software gives better response and more effective power delivery
• Full power available in Trail mode and longer range through greater motor efficiency
• More intuitive customisation
• Less likely to trigger the dreaded W013 error code

Shimano has launched the long-awaited successor to its mid-mounted E8000 STEPS e-bike motor: it’s called the EP8 and it boasts an array of improvements over the old unit, including more power, less weight and a whisper-quiet ride. It brings a much-needed boost to performance that allows it to compete with the likes of Bosch’s gen 4 Performance Line CX and the Brose S-Mag fitted to the Specialized Turbo Levo and Specialized Turbo Kenevo. Because it uses the same mounting points as the old motor, you’re going to be seeing a lot of bike brands upgrade their bikes to the new EP8 for 2021.

New magnesium casing saves 300g over old aluminium version

Launched back in 2016, Shimano’s STEPS E8000 quickly became the market leader for mid-mounted e-bike motors thanks to its light weight and compact dimensions that allowed bike designers to radically improve the handling of their electric mountain bikes. Since then, Brose and Bosch both raised the bar with their latest offerings and left the E8000 unit feeling clunky and underpowered. This new unit brings Shimano right back in the game in the premium e-bike market. Let’s take a closer look at the improvements and how the EP8 stacks up against the competition.

Smaller by 10% in volume than the E8000, but the Q-factor remains at 177mm

More torque aids climbing and acceleration

Shimano has boosted the torque of the EP8 by 15Nm over the old E8000 to bring it in line with the 85Nm Bosch Performance Line CX unit. On paper then, the two are now evenly matched. On the trail, however, the Bosch still produces a noticeably stronger kick, whether faced with a trail that’s ramping up in gradient or accelerating out of a slow, flat corner. Yes, it feels stronger than the E8000, but it doesn’t quite feel as powerful as the Bosch or the Brose S-Mag. Does this matter? Not really. There’s still sufficient grunt to get up some impressively steep and challenging climbs, so while it won’t win any impromptu traffic light grand prix, the power is certainly ample. While we’re on the subject of torque, the E8000 required you to keep your feet off the pedals when you turned the bike on, or you’d get a W013 error code and have to start the process all over again. The EP8 is much better in this respect, so you can rest a foot on the pedal when you power up and not suffer the warning. But if you really lean on the pedal, or instantly go to pedal away, you will probably still trigger it.

Expect to see most brands update to the new EP8 motor for 2021

Smaller and lighter

Already one of the lightest and most compact motors on the market, Shimano has really pulled out all the stops on the EP8 to lose around 300g and 10 per cent volume compared to the E8000. It’s visibly smaller than the old unit, giving additional ground clearance and helping to create sleeker frame designs. The EP8, with its new magnesium casing, weighs a claimed 2.6kg compared to 2.9kg for the aluminium-encased E8000, while both Bosch and Brose are around the 2.9kg mark.

New one-way clutch and gears are said to improve efficiency and help engagement speed

The quietest motor on the market?

For some riders, the whine of an e-bike motor ruins the peace and tranquility of the great outdoors. Or it could just be that no one wants to advertise the fact that they’re not doing all the work themselves. Either way, the volume of a motor is certainly a factor for some buyers, and the new Shimano EP8 is hands down the quietest system we’ve ridden. It’s almost silent, even when demanding high levels of power, and alongside the old E8000 unit, the difference is like listening to music through headphones versus blasting it out through a speaker. If you want to sneak past analogue riders on the climbs without being called a cheat, the new Shimano EP8 is the motor for you. Sadly there is a noticeable rattle from the clutch mechanism when coasting on rough terrain, but it’s less noticeable when you’re focussed on a technical descent.

Less drag

Shimano claims the EP8 is 36 per cent more efficient than the E8000. Or think of it another way, there’s 36 per cent less drag in the motor mechanism. This should mean that you can ride further on the same battery power, that there will be smoother reduction in power when you reach the 25km/h limit, and it will be easier to pedal when the motor cuts out. Shimano has achieved these efficiencies through a new seal structure and redesigned internal gearing. A new clutch also helps while simultaneously providing a more rapid and solid engagement between the cranks and the motor.

More fins means more surface area for heat to escape

Better heat management

Although this is not a factor we’ve ever encountered on UK rides, the chance of overheating can be a very real issue in warmer parts of the world. Leave a bike out in the sun while you’re having lunch then go straight into a big climb and there’s a chance you’ll overheat the motor. The EP8 aims to improve this with more cooling fins, which creates a greater surface area for dumping heat.

Updated software gives full power in Trail mode

One of the main criticisms of the E8000 is that Trail mode never really gave enough grunt for really challenging climbs, so you had to be regularly toggling in and out of Boost to maintain flow and manage battery life. In fact, Shimano’s own graphs show that you need to be putting out around 100Nm of torque to get maximum assistance from the motor in Trail mode. Competitors, particularly Bosch with its eMTB mode, had nailed this aspect, allowing you to set-and-forget the power mode and concentrate on riding. Changes to the software with the EP8 means this is no longer an issue, as you can now access the full 85Nm of torque in Trail mode with only 60Nm of torque from your legs. In Boost mode, this shrinks to around 20Nm. The upshot is that you can take on more challenging climbs with steeper gradients and technical features while remaining in Trail mode.

At the other end of the spectrum, Shimano has also tuned Eco mode to give you more range. It claims an extra 20 per cent on flat terrain compared to E8000, but how that translates to the up/down style of most mountain bike rides, we’re not sure.

Improved customisation options

To help riders get more out of their e-bike and personalise the performance to their unique needs, Shimano has updated its E-Tube app. This can be used to customise various parameters in each power mode. If you’ve ever used the Specialized Mission Control app, then the new E-Tube interface will look familiar. You can tune the characteristics (torque curve) of the motor, the maximum torque in each mode and how quickly the motor reacts when you start pedaling. There are also two factory-set profiles that you can use to quickly toggle between on-the-fly without having to connect to the E-Tube app. Profile 1 is the default setting and Profile 2 is said to give a sportier, high-performance assist. Access these through the handlebar display and control unit and you can also save your own profiles should you wish to have one that prioritises, for instance, range, and one that gives you the most aggressive power delivery. We’ve now had the opportunity to play with the new app a little, and it connects easily and is intuitive to use. If you’re looking for a sporty response for technical mountain biking, there’s not much point in changing the stock settings though.

New 530Wh BT-E8036 battery increases range and weighs 3.46kg

Bigger battery

To complement the EP8 motor, most high-end full-suspension e-bikes will come fitted with the 630Wh BT-E8036 battery launched earlier this year. This internal battery pack gives an extra 25 per cent range, which should roughly translate into another 200m+ of climbing per ride. Note, this isn’t necessarily backwards compatible with all existing Shimano-equipped frames, as the battery is physically longer. You’ll have to check with your bike’s manufacturer as to whether it will fit in the frame.

>>> How to get the most range out of your e-bike

How the Shimano EP8 motor rides

Spark up the EP8 and the first thing that strikes you about it is the noise, specifically the lack of any. This motor is seriously quiet. It’s much, much quieter than the old E8000 and, without getting a sound meter out, we’d probably say it’s the quietest full fat motor on the market. It’s not silent, but you barely notice it while riding, and the sound of the tyres generally drowns out the noise of the motor. If you feel embarrassed overtaking riders on analogue bikes, you’ll be spared any blushes until you’re right up behind them.

The next thing we noticed is how much more solid the engagement is. No longer does it occasionally feel like you’ve got a loose crank or wobbly bottom bracket. It’s now tight and there’s a lot less lag from pushing down on the pedal to firing up the motor. However, there is a slight rattle from the clutch when you’re descending over rough ground and the motor is not engaged. It sounds a bit like chain rattle, so nothing too serious, but we did notice it.

While the headlines will all focus on the power increase, in reality those extra 15Nm don’t dramatically change the ride feel compared to the E8000. It feels more like a step forward than a leap ahead, and back-to-back with the latest Bosch or Brose, the Shimano definitely doesn’t feel quite as punchy – although it’s possible this is more down to software tuning than raw power outputs. That said, the EP8 has got plenty of grunt and can still tackle climbs you wouldn’t dream of attempting on a naturally aspirated bike. The enhanced Trail mode is definitely an improvement too, such that we no longer felt the need to use Boost as regularly, and we love the fact that the updated app gives so much more scope for tuning the ride characteristics depending on your priorities. That said, we haven’t had the chance to try it out yet, so we’ll update this page when we have.

In terms of sheer climbing ability, the EP8 doesn’t really open up any more terrain over the Bosch Performance Line CX or the Brose S-Mag fitted to the Specialized Turbo Levo and Kenevo, but it also doesn’t limit your boundaries. Where it does fall short of the Bosch is on climbs with steps and ledges to hop up, or fallen logs to get over. While the motor overrun on the Bosch gives you that boost of power to smoothly propel you over an obstacle when you stop pedalling, the EP8 is much more subtle in this respect, with less rotation after the cranks stop turning. So it’s much harder to both maintain momentum and stop your pedals or motor sumping out on whatever you’re trying to clear. Ultimately this is just a software variation, but for technical mountain biking, it translates into a massive advantage. Let’s hope Shimano comes up with an update to improve this aspect of its performance, because in almost every other respect it’s on par, or ahead of its rivals.