Your guide to all the most popular mid-mounted e-bike motors on the market, from Bosch to Brose to Yamaha, Fazua and Shimano.

Brose, Bosch, Shimano… which has more power, which packs more battery punch, which is more reliable? Our quick guide to e-bike motors has the answers.

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After the government announcement of the removal of the £1,000 limit for its tax-free cycle to work scheme, e-bikes were brought into the equation for the first time. Is this the tipping point that makes e-bikes the norm, rather than the minority, on Britain’s trails?

With the potential to save around 30 per cent off the price of a new bike, the UK could be poised to see a similar growth spurt in new e-bike sales to that witnessed across the channel in countries such as Germany, Austria and Switzerland.

And it’s here that e-bikes are attracting a completely different customer, one brought up on brand names from the household and automotive sectors. E-bike buyers on the continent are walking into stores asking for a Bosch bike or Brose bike, rather than a Specialized or a Trek – the sticker on the down tube carrying less currency than the one on the motor.

So, in this brave new world of motors and batteries, watts and amps, which of the three main suppliers in the e-mtb market is the ultimate super power?

Power

This is an easy win for the Brose Drive S-Mag. On paper it produces up to 90Nm of torque and supports your effort by up to 410 per cent. In the saddle that power is equally impressive, even when you’re revving the cranks, and the torque really packs a punch when accelerating and tackling steep technical climbs.

Next, and not far behind, is the new Bosch Performance Line CX. It can’t quite match the Brose for either power or support (340 per cent and 85Nm) but in most situations it feels strong as an ox with stacks of power to lean on.

Lagging a little behind is the Shimano STEPS E8000. It lacks a bit of torque compared to the competition (70Nm) and you’ll notice that if you’re riding with people equipped with Bosch or Brose. In isolation, it’s not normally an issue, unless you weigh a lot or like drag races and seeking out the gnarliest climbing challenges around.

However, Shimano has just released its brand new EP8 motor that, on paper at least, brings the torque figure up to 85Nm and makes that power a lot more accessible to the rider through brand new software. The new Trail mode lets you tap into all that power and tune the characteristics to your heart’s content with the new e-Tube app. So far we’ve been impressed with the new motor’s light weight, low noise, compact size and improved engagement, but it doesn’t quite feel as powerful as its two main rivals.

Bosch Performance Line CX

Response

Tying for top spot here are Bosch and Brose. Need to get going again on a climb or out of a corner and both of these motors deliver a near instantaneous reaction. The Shimano system is by no means dim-witted, but it’s not quite as responsive as the two German systems.

Battery capacity

The bigger the battery, the further the range; it’s as simple as that. And in case you weren’t sure, more range equals more money and more weight. At the moment there’s no clear winner here.

For Brose systems, Rotwild offers 750Wh and Specialized 700Wh on their top of the range models. However, Focus’s piggy-back TEC pack system (standard on the Focus Jam2 and Sam2) plugs into the Shimano motor and gives you two 380Wh batteries, equalling 760Wh, and this is now included in the price of the bike. Bosch’s revamped Performance Line CX has a 625Wh battery option that provides a decent range in a single internal unit that doesn’t impede the handling of the bike. Now Shimano has also updated its battery line-up to include a high capacity 630Wh unit. Don’t need the extra range? Shimano also offers 504Wh versions of its internal and externally mounted power packs.

Control and integration

Specialized’s Brose switch control unit is our current favourite, as it’s neatly engineered to be discreet but easily accessible, and you can run a small remote on the bars, or rely solely on two top tube mounted buttons. Additionally, Specialized’s Mission Control smartphone app lets you tune the motor, check range and troubleshoot problems quickly and simply.

Shimano EP8

Shimano’s new EP8 motor

Shimano hooks up a sleek and minimal push-button E7000 remote to a small display unit tucked behind the handlebars. It’s easy to change modes, doesn’t compromise your dropper post remote position and lets you see just enough information to help you manage battery life.

Bosch lags behind the other two in the display/control unit department for serious mountain biking, with options that seem designed mainly for leisure riders. There are several options in the line-up, including the new Kiox colour display and Purion integrated display/control unit, but all of them are bulky and overcomplicated compared to the competition.

Noise

Another win for the Brose unit here, as its belt-drive internals mutes the whine. Although the new Shimano EP8 motor is similarly quiet. Bosch is next in line in this department, but it’s still not much better than the vocal Shimano STEPS E8000.

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Shimano STEPS 8000

Reliability

Now the Bosch Performance Line CX is a year old, Bosch obviously feel confident enough in its reliability to unlock an extra 10Nm of power from the unit. From our experience it’s also been reliable if maintained and looked after properly. Shimano’s E8000 has also proved mostly reliable, although it does depend to a dgeree on the specifics of the electrics. Some bikes may be more prone to water ingress than others, and this can cause issues. At the moment, the most failures we’ve seen have come from the Brose S-Mag fitted to Specialized Levo and Kenevo models. This has been a mix of water ingress causing issues with the electrics and connections, and problems with the belt drive failing within the motor itself. While Specialized has quickly moved to address this with enhanced warranties on its e-bikes, that won’t help if your motor stops working miles from home.

Brose e-bike motor on Specialized Turbo Levo

Verdict

With the e-bike market in a constant state of flux, today’s market leader can fall behind at the flick of a switch. At the moment, for pure ride experience thanks to its rapid response, intelligent eMTB mode, powerful motor and addictive overrun feature that lets you power over steps and ledges on climbs, we’d say the Bosch Performance Line CX edges it. But, the displays and control units are bulky and awkward to use. On the other hand the new Shimano EP8 is lightweight, smooth, ultra quiet and boasts one of the best rider interfaces on the market. However it feels a tiny bit down on power compared to the Bosch, and lacks the same level of overrun, so isn’t quite such a weapon on technical climbs. While the Brose S-Mag is seriously powerful and, when fitted to Specialized’s e-bikes, comes with the best rider interface and battery range on the market, the current failure rate means it has dropped down our list of favourite motors.