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Bosch eBike 350w 250w Difference

Whats the difference between the 250w & 350w Bosch eBike motors? – Explained

By Martin Brown on February 3, 2014

A lot of people ask me – What exactly is the difference between the Bosch eBike 250w motor and the Bosch S 350w motor? So I have decided to make a little write up to explain this in more detail, it should also save me a fair amount of time on the phone each day too!

Bosch eBike 350w 250w Motor DifferenceSo to start off the Bosch 350w S motor on paper is more than the 250w.. Right?.. Yes. However, don’t look at this as top trump cards and decide you need a 350w Bosch motor otherwise you won’t be able to get up that huge hill you live on top of.  Did you know that both the 250w and the 350w Bosch motor are exactly the same? They both share the same internals, they both use the same battery & head unit etc. Some rumours have spread that the 350w has ‘metal internal gearing’ and the 250w motors do not, again this is not true, both motors are produced using the same components.


So exactly what is the difference you may ask?

Well, they are programmed slightly different. The 350w speed pedelec has an assisted speed to 45 km/h and the 250w motor is assisted to 25 km/h. Everything else is exactly the same. The maximum and minimum assistance levels, the maximum torque & the motor RPM all stay the same between both types. Oh and the 350w motor has a Red Bosch logo on the side whereas the 250w has a grey logo, so they are easily distinguished.

Also, it’s worth noting the new CX line developed with more torque and assistance (not available in the 350w version. See the table below for factual differences:-


Bosch Performance 350w

Bosch Performance CX 250w







Assisted Speed

45 km/h

25 km/h (50 km/h Tuned)

So whats the point in 2 drive types?

Its simple.. One can reach higher assisted speeds than the other.


Who uses Speed pedelecs?

Some European countries have guidelines and procedures in place for Speed Pedelecs (eBikes over 250w & 25 km/h). For example in Germany certain laws allow you to register your 350w eBike and pay a yearly rate to ride a Speed Pedelec on the road. There are certain rules that stipulate a cycle helmet must be worn, the eBike must have a side stand, lights and a licence plate holder.  Over here it is classed as a motor vehicle so you would have to be licensed and hold appropriate insurance. There is currently no regulations in place to license a Speed pedelec.

It’s worth noting at this point that the German market is way ahead of us here in the UK. So if their market is so advanced and they have regulations in place is everyone on an ‘S’ pedelec? You would think so, however, you’ll be surprised to hear that out of the 400,000 electric bikes sold annually in Germany, only around 5,000 of these are Speed pedelecs. Only a tiny percentage ey?


Is it illegal to use a 350w Bosch motor here in the UK?

On the road… Yes (Unless you take the appropriate actions to license the eBike). You may wish to use the eBike on private land with the permission of the land owner. If you do use a 350w motor here on the road, you are riding your eBike illegally. You do run the risk of having your eBike taken by the authorities. If you are involved in an accident, you are responsible for the damages/injury involved for both yourself and the 3rd party.


So I want a 250w Motor but how can I go faster?

We do provide a Bosch speed tuning dongle for all of our Bosch powered eBikes. This is a device that is ‘plumbed’ into the motor that can alter the speed cut off of the eBike. It allows you to travel as fast as you want to be assisted by the motor off road (private land) of course. This can easily be unplugged when you are on the road, then easily plugged back into derestrict as required. By using a 250w motor it means that you have a legal bike that can be easily derestricted when needed.

Speed Tuning Dongle de-restrict Panasonic & Impulse electric bike motors cut off speed

Remember the 250w Bosch motors give exactly the same assistance and torque levels as the 350w motors. In fact, a 250w motor with a dongle installed will travel at faster-assisted speeds than a 350w motor on its own. Crazy huh!?

A little more can be read about the speed tuning dongles here – How to derestrict a Bosch Electric Bike.


Also, it’s worth noting that we are only supplying dongles for our own eBikes with the latest Bosch eBike motor.

About Martin Brown

Martin has been in the electric bike industry for over 10 years & has helped it grow from the start. Promoting eBikes across the UK at events & offering the very best advice, tech articles, blogs & videos. In particular Martin is a major player for progressing the use of eMTB's, today owner of - The UK's largest eBike supplier specialising in Bosch & Yamaha, good quality European eBikes.