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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.


  • Giles Bradley

    Hi. I’ve just got a new e-bike with the Bosch Intuvia display. Although the manual claims that the wheel circumference can be adjusted, actually this isn’t the case and the retailer admitted that it’s ‘factory set’. Annoyingly the speedo over-reads by about 7% and I’d like to be able to rest the wheel circ. Is this something you can do by ‘hacking’ into it?


    • Hi,

      It sounds like your dealer is not too hot with the Bosch system, a shame as they are there to help you.
      Yes we can ‘hack the system’ using our diagnostics kit and know how.
      It depends what model and what Bosch system it is running to determine if you can set it yourself or not. The Performance range can be adjusted by the end user through the Intuvia diaplay by holding the Reset and Info buttons together to access the secondary settings.

      Most of the other types are locked and cannot be altered by the end user. Unfortunately we only work on our own bikes sold through our establishment. Always factor in the back up and support you will be getting through which dealer you decide purchase your ebike from.


      • Dick Tracy

        So, if you make the wheel circ smaller by ajusting it in the Intuvia, the bike will go faster because it ‘thinks’ it has to make more rotations?


        • Martinebikeshop

          It will not work. It will only minutely adjust the range indicated on the display.

          • Dick Tracy

            Ok, tnx. But is there any software in the intuvia, or in the bosch motor? I mean, is there a way to speed up the bike by changing the software instead of using a kit?


          • Martinebikeshop


  • Hugh Leighton

    I am seriously thinking about buying an e-bike powered by the Bosch active system. According to
    “the motor shouldn’t have a maximum power output of more than 200 watts if it’s a bicycle and 250 watts if it’s a tandem or tricycle”
    – yet the Bosch system fitted to a bike is 250w – does this make it illegal for road use in the UK, and if not, why not?

    • Hi Hugh,

      Thanks for your message, yes you are correct that according to UK law the maximum allowed is 200w and 250w on a tandem.
      EU law allows use of a 250w motor and we are now part of the EU. The UK law is set to change in 2016 to encompass these rules.

      In the meantime, we have been allowed to sell 250w bikes and ride them around here on the basis that the law is set to change anyway.
      Anything past 250w is not allowed though.


  • BoB

    When free wheeling,ig down hill does any of the bikes recharge them selves for greater range?

    • Hi Bob,

      We tested this. It is really not worth it. We worked out you would have to add about £180 to the cost of the bike for the regen equipment.
      It would also add a level of drag to the bike. Which defeats the point.
      Also we noted that we only got 2% charge back from the regen equipment.
      So for example if you were to travel 100miles, you would get 2 miles of charge back.
      The disadvantages far outweigh the advantages. Its really not worth it.


  • kilou

    I don’t understand: while both motors are similar (same components, same torque) one is 350W and the other is only 250W. Installing a dongle on a 250W unit will just remove the speed limit of 25km/h but it will not change it into a 350W unit. Some people using the dongle mentionned that it’s possible to reach 35km/h with a tuned 250W unit although 50km/h should be achievable in theory. However 250W is just too weak to reach such speeds, for these a 350W or more is needed.

    So while agree that both motors are the same mechanically, the software management is different and the 100W difference between the 2 should bring some benefits, especially at high speeds. Or am I missing something?

    • Martinebikeshop


      Firstly the gearing would have to be altered to reach really high speeds, no matter what drive unit is fitted. It is a push bike at the end of the day.

      I would suggest to ride both in real life situations and gather your own feedback as to what will work for you.

      You say 250w is not capable of reaching such speeds? This does not make sense?.. The most amount of assistance and torque is used from a standstill. When up to speed it is easier to maintain cadence and the motor does not work as hard. So its pretty much the reverse of what you are suggesting.


      • kilou

        Riding from a standstill requires torque. To this end both the 250W and 350W have 50Nm max torque (classic+) and go equally well at low speeds in steep hills. However power is needed for speed and the amount of power increases tremendously to go for example from 40km/h to 45km/h due to aerodynamic resistance and the motor has to work actually harder to maintain those speeds. 250W units may achieve this (with a dongle) if the rider pushes really hard on the pedal. With the 350W it’s already easier…and with a 500W rear motor it’s even easier. For me there is a reason why the S-pedelec version of the Bosch unit is 350W and not just a dongled 250W unit… Same hardware but a different controller and software that allows more juice in the S-pedelec version to reach high speed.

    • Simon Dowsett

      In this case, Power is a function of torque and angularVelocity (rotational speed). The 250W version is geared to have slightly more torque, but it is electronically limited to just 15mph! In contrast, the 350W version has almost twice the speed which makes up for the deficit in torque and then some. If you remove the artificial limiter on the 250W version, it can spin faster whilst providing the same torque and thus power output increases.

  • jano

    hello, you talk a lot for the 250w motor, but there is a dongle for 350w engine? if so what would be the performance achieved? (It will already a 45km / h)
    60km / h if the motor would be possible without the risk of engine failure?
    thank you

  • Colin Dale

    I bought a German e-bike last year which the manufacturer supplied with a 2014/15 Bosch Performance Line motor with the intention of registering it for road use and obtaining insurance etc. Registration took 5 months because the new motor line had to be added to the German authorities approval database and so issue of the Certificate of Conformity was delayed (and the explanation regarding this was on a photocopied piece of paper in German!). Because of this confusion I also arranged for the e-bike to go through a partial single approval inspection at VOSA.
    Once I had the registration number I then looked for insurance – Over a period of six weeks I contacted over 50 insurers or brokers – none of whom would over suitable cover – the pedelec insurers and home/content insurers do not cover e-bikes which have been registered for road use – the motorcycle/moped insurers only cover makes and models included in the Association of British Insurers database and there are no s-pedelec manufacturers on the list. If anyone has had success in this I would love to know who to contact.,
    As insurance cannot be obtained I then had to make a SORN or face a fine of £100.
    Two questions:
    1. Is it possible to make the motor switchable between the 15.5 and 28 mph levels of assistance?
    2. The Intuvia supplied does not have the walk function – would a replacement Intuvia with a walk button re-instate this capability?
    Any advice/suggestions gratefully received.

    • Martinebikeshop


      Please consult your dealer for any after sales support / advice. They are here to help you.

      We can supply a tuning kit which is switchable, however we only supply it on bikes purchased from us.

      The walk function can be enabled by your dealer via diagnostics.

  • Geir O

    What is the difference between an 250w Bosch and an 350w Bosch when you think on use of energy? Normally you kan go about 80 km (400wh battery) with an 250w Bosch and 25 km/h. If you go the same distance with an Bosch 350w and with speed about 45 km/h?

    Geir O from Norway

    • Martinebikeshop


      Yes it uses a little more energy. As you can see by the range predictions on our website.

      That said you cover more ground in less time.

  • Nice that It allows you to journey as quick as you want helped by the engine off street

    • Martinebikeshop


  • Gary Erickson

    Bought two Cube 400 pack, Bosch E-Bikes, both mine and my wife’s bikes have lost power while riding up hill on several occasions, at low speeds. We both had the “dongle” installed to increase max speed limit. Could dongle that the problem? Could the dongle have been installed wrong? Today when it happened, I placed the provided magnet to bring back to original speed limit, (max 25kph). We wonder if by doing that, does it go back to factory setting and system. I didn’t have a problem after setting to lower max. But? We want to speed, on private roads of course! And maybe tomorrow it will happen again? Mystery…

    • Martinebikeshop


      The kit is probably installed incorrectly.
      Please contact your place of purchase for any after sales support / parts you may require.

  • James Russell

    Can you adjust the point at which the bosch performance line kicks in?

  • Glen Aldridge

    I’d like to know just what criteria is used to determine the ‘safety’ threshold for power assisted bikes. Where are they getting the data to substantiate the power limits? SInce non-assisted pedal bikes, recumbents or trikes can hit speeds of over 60km/hr. having a power assist that is well below that speed threshold seems archaic. In Canada we have a max power limit of 500 watts, U.S. States have up to 750 watts, Europe – 250 watts so it seems obvious that whatever criteria the power limits are based on are groundless.

  • Nice that It allows you to journey as quick as you want helped by the engine

  • susti

    More flat road/off-road speed is ok, but what if you want the ekstra power up hills. Will the dongle give more torq/power at lower speed for getting up that last hill more elegant than with the 250w, and even the 350w?

  • Richard Bailey

    Hi- great explanation..
    I have inherited a KTM Macina from my brother but the battery has as i many large Lipos lying around my garage (i race large scale rc cars) i was looking to build a new battery ..but im a little stumped as to what the 5 connectors are on the battery ? I assume the 2 larger one are for the main power- but what are the 3 smaller ones? are these for the BMS?
    any help would be much appreciated-