Bosch enters the lightweight e-bike motor market with the Performance Line SX motor

Bosch says that it's new Performance Line SX electric bike motor sets a new standard for power to weight in its line-up.

The new motor is geared towards electric gravel bikes, as well as electric hybrids and lightweight electric mountain bikes, with a system weight of around 4kg and a 2kg mid-mounted motor. It also includes a new riding mode and compact battery options.

Bosch says that the 250W continuous power Performance Line SX motor provides a maximum torque of 55Nm and can generate 600W peak power to help you get up steep inclines. It’s also designed to deliver power at higher cadences.

Bosch has decreased the motor’s weight by using a magnesium alloy housing. It’s also reduced the Q Factor to 160mm and claims a new standard in its motors’ noise output.

Once your speed gets over the 25kph cut-out limit, Bosch says that the new motor provides 50 per cent less resistance than its previous electric bike motors and claims that this is barely noticeable.

There’s a new Sprint mode which helps you to get up to maximum speed quickly, and the motor’s power output also increases as you pedal faster.

Alongside the new motor, Bosch has also released a Mini Remote Dropbar control unit. This sits to the left of the stem on a standard width 31.8mm handlebar and is smaller and less intrusive than Bosch’s previous control units, although the brand suggests using the Kiox 300 display if you want extra data.

New battery and range extender

The new Performance Line SX motor is paired with a new 400Wh battery. Accounting for the other half of the 4kg system weight, it is the lightest battery that Bosch has in its line-up. The high energy density, Bosch says, makes it possible to integrate it into the bike frame’s down tube.

Need more range? You can plug in Bosch’s new PowerMore 250 range extender, which as its name suggests provides an extra 250Wh of battery capacity. It’s a 1.6kg water bottle-sized package, although, unlike many range extenders, it doesn’t actually fit in a bottle cage, but needs its own mount.

The new motor system is expected to become available on electric bikes this autumn.

New Smart System portfolio 

Bosch has also released updates to its Smart System, which is a modular range of products that link the new motor and battery to controllers and displays. The Smart System integration also now extends to the Active Line and Active Line Plus motors, providing a more connected solution for more leisurely urban and trekking use.

There are new controller options as well. Bosch says that the latest Purion 200 controller is not just compact, but its colour display has high resolution. An ambient light sensor also ensures that it’s readable in changing light conditions.

If you want more data, you can hook up a second Bosch display unit or a smartphone to the Purion 200, allowing you to show your route and navigate without needing to dedicate part of the larger display's screen to showing battery and assistance levels.

Also new is the large format Kiox 500 2.8-inch screen display unit. Bosch says it’s around 40 per cent larger than its existing Kiox 300 unit, so it’s easier to read quickly. It also includes audible cues if you go off-route. Bosch promises a future upgrade allowing you to customise the Kiox 300 and 500 units and reorder the data fields – something that the best bike computers have offered for years.

Smart System also enables automated gear shifting for hub gear e-bikes equipped with the Rohloff, 3x3 and Enviolo gear hubs.

Another new product is a premium subscription service from Bosch. Flow+ includes a bike alarm for bikes equipped with the Connect Module, with Bosch promising added functionality in future. The Flow+ subscription is priced at €4.99 per month or €39.99 for an annual subscription, with the first 12 months free of charge.

Bosch has also added a new external frame and rear rack-mounted batteries of 400Wh and 500Wh capacity, with the lightest weighing 2.2kg. Geared at urban hybrid electric bike use, the rack-mounted batteries have enhanced anti-theft protection and a smaller profile than Bosch’s previous batteries. It will also be possible to double up batteries for larger capacity for cargo bikes or longer rides.

Finally, there’s a new 2A charger that’s lighter and smaller than Bosch’s current 4A charger, making it easier to carry with you.

Bosch still behind for road/gravel use? 

Despite all the shiny new stuff, it’s fair to say that Bosch is still behind the curve in the lightweight electric bike and electric gravel bike markets, although it's well positioned in the electric mountain bike and urban e-bike spaces. 

The Mahle X20 rear hub motor, for example, has a claimed weight of 1.4kg, with the 300Wh battery weighing 1.8kg for a total system weight of 3.2kg and with frame-integrated controller options. It puts out the same 250W/55Nm as the new Bosch Performance Line SX motor. Mahle's motors are a popular option, appearing for example on the Scott Addict eRide.

Another compact motor option that’s finding its way into lightweight electric bikes including the Trek Domane+ SLR and the BMC Roadmachine AMP X is TQ’s mid-mounted HPR50. This has a claimed motor weight of 1.85kg and its battery weight is around the same, for a 3.7kg system weight. It’s super-compact and pushes out 250W/50Nm. TQ also has very compact satellite-shifter style assistance level controls and integrates with a cycling computer.

And brands including Mahle and Specialized have had bottle cage range extenders that really do fit in a bottle cage for years.

It will be interesting to see which brands choose the new Bosch Performance Line SX motor for  new electric gravel and electric road bike use come the autumn.