Which Bosch Motor for your E-bike?

Bosch are the market leaders in motors for electric bikes. This is for a good reason; they have invested heavily in the market, they continue to innovate and they provide a great service to the bike industry. The vast majority of the bikes that we have are powered by a Bosch motor. Of course there are other motors out there such as Shimano, Yamaha and Brose. However, we believe that for a number of reasons the Bosch motor is still the one to beat.

For 2020 Bosch have updated their motors and this is most especially with the highly praised Gen 4 Performance Line CX motor. So what is the best motor for you and how do the new motors differ from the previous generation?


Performance Line CX Generation 4

This new motor from Bosch is the biggest change that Bosch have made in their line up since 2016.

The new Performance Line CX Generation 4 is the most powerful motor in the Bosch range. The highlights when compared to the previous version are that it is lighter (by some 25%), smaller by almost 50% and it packs more torque (now 75 Newton meters) and hence assistance (now 340%). The previous version of the motor had 70 Nm of torque and the assistance level was 70%. There is no doubt about it that this is a step up from before but it is more evolutionary rather than revolutionary.New Bosch Performance Line CX Gen 4 motor

The additional assistance that you can now get is great but for most riders is not necessary and the improvement is not massively noticeable. The reduced weight is very welcome with about a kilo of saving in weight. This is enough to notice.  The reduced size means that the motor is more discreet than ever.

Another important change, perhaps more important than the reduced weight and increased power is the change to the gearing. The previous version has a very small sprocket for the front chain ring because the motor was geared inside. The effect of this was increased resistance and also with a smaller sprocket there was potentially more wear on the sprocket and the chain. The new motor has removed these issues and the rider’s pedalling power is now more effectively translated into power, whether the power is on or not.

This motor is typically packaged with mountain bikes and other performance bikes. It is for the sportier rider or for someone who wants as much assistance as possible.  For most riders we would say that while all this power is great you should not by any means discount the other motors which give plenty of assistance.

Performance Line 

Along with the Performance Line CX motor, this motor, some times called the Performance Line Cruise has also been updated for 2020 with the same modificarions – i.e. lighter, smaller, more powerful and with the motor disengaged from the transmission. it weighs the same as the CX motor with a torque output of 63 Newton meters. The assistance level has been increased from 275% of the previous version to 300%.

This motor comes with a number of our bikes – for example the Moustache X road 3. This bike is designed an all purpose bike, capable of going off road but also practical with mudguards, lights and a rack to carry luggage. This motor is a great choice for those looking for lots of assistance but also capable of longer distances. With average usage (using all 4 modes in reasonable conditions) the Performance Line motor is capable of 10 more kilometers compared to its more powerful cousin.


Performance Line Speed variant 

The Performance Line Speed variant is for ‘speed pedelecs’ capable of an assisted speed of up to 45 km/h or about 30 mph. Speed pedelecs are not legal in this country without a special license and clearance from the DVLA. We can help you through this process on request. As this is not a motor that comes on standard bikes in the the UK it is beyond the scope of this article.

Active Line Plus 

This motor came to the market in 2018. It is the slightly heavier, more powerful cousin of the Active Line (below) , the Active Line Plus weighs in at 3.2kg so is still very light despite the boost in speed and power.  The Active Line Plus maintains many of the benefits of the Active Line with noise reduction, no resistance, a small, sleek build, and harmonious acceleration all still noticeable advantages. However, the Active Line Plus improves on Torque strength with 50Nm, and assistance drive available with 270%, making it easier to break out of the city limits and power over off-road trails. If your ride is quite hilly and you are looking for a bit more help then we would recommend this over the plain Active Line. It is one of the newest motors in Bosch’s range, and therefore we expect to see it on more models in future. 

Active Line

Until the new crop of motors this was the lightest of Bosch’s motors weighing in at only 2.9kg.  The Active Line 3.0 is a sleek motor packing its power into a tightly wrapped, compact package. Bikes with Active Line motors is noticeably more compact than the other motors in the range and can even make it difficult to tell apart from their non-electric counterparts, as the motor snugly fits in among the pedals and does very little to distort the silhouette of the bike.Bosch Active Line Motor

This was the first of the Bosch motors to feature the normal sized chain ring and hence the disengaged motor from the transmission system, ensuring that when you are using the bike without the assistance you are getting maximum efficiency from your pedalling.


Bosch have really upped their game in the last couple of years. They continue to bring out great products and make life very difficult for the competition. The motor received some criticism in the past because of the size of the front sprocket and the resistance that this created. Now that this has been replaced with a standard sized chain ring it is hard to think of an area where the motor can be criticised. Our view is that any bike that is equipped with a Bosch motor has been given the best start in life!

The table below summarises the stats for the various Bosch motors. The range figures that have are quoted assume a 500 watt hour battery and an average usage of all 4 modes of assistance in favourable conditions.  Torque and Assistance levels are the maximum that can be achieved in the Turbo level of assist.


Bosch Motors

Active Line2.9 kg40 NM250%56 miles
Active Line Plus3.2 kg50 NM270%52 miles
Performance Line2.9 kg65 NM300%47 miles
Performance Line CX Gen 42.9 kg75 NM340%41 miles