Magnificent Machines Maintanence TSDZ2 Motor projects

Experimenting with the TongSheng TSDZ2 Mid drive system Part 4

see Part 3

Its been quite a while since I last posted about the TSDZ2 motor. and I think its well worth an update as things have moved on quiet a bit!

To start with I wanted to address a few general questions about the TSDZ2 motor that I have been asked by a few people, who are interested in purchasing one.

There are many different types of TSDZ2, which one should I buy?

There are actually only 2 different types of TSDZ2 motor ( if we disregard the coaster brake version for now)

36V and 48V motors

The difference between these two version is that each is designed to spin the motor ( not the cranks) at 4000rpm at the rated voltage (36 or 48v) when using stock firmware.

However if you put a 48V battery onto a 36V motor ( and you use the opensource firmware) then a 36V motor will spin quicker than a 48V motor, but the 48V motor will have more torque and little spin slower.

So the main decision really is speed  vs torque.

Personally I ride with a high cadence of around 90rpm (at the crank) and at times and I was finding that the stock firmware on a 36V motor  was spinning too slow for me. What people may not know is that the motor will not easily let you spin it quicker than it wants to go. evn in very low gears if the motor is under power it will cap out at 4000 RPM or about 75rpm at the cranks.


So what about all the different versions 250w,350w,500w,750w?

It does not matter what voltage motor you choose the wattage is just a limit in the software (firmware) on how many amps the controller will allow.

This is the main hack that people do to the stock firmware to trun a 250w motor into a 500w motor just increase ethe hex value in the firmware that limits its to 16A.

If you just want to use the stock original firmware but change the wattage this guide has all the details..

This is also the same tool used to flash the opensource firmware! 🙂

This is a good start when hacking the TSDZ2 as you get to feel what your motor does in stock form with your battery unlimited.

Why would I use the Opensource Firmware if I can just run the stock firmware for 750W?

Well this all depends on what you want out of your e-bike really.

Power is one thing, but what about the loudness, smoothness of the motor maximum cadence, efficiency or ability to fine tune the number of levels of assist and what power each level gives. If you want the flexibility to tune the motor to meet your personal needs better then the Opensource firmware has way more options to help you.

Then there is also the ability to use different displays that can show more information like battery voltage, Human wattage, motor wattage, Battery life etc.  In effect giving the TSDZ2 motor many more of the features you expect from the top end Bosch shimano drive units.

So what have I changed on my bike since my last blog post?

Well there have been a few new firmware versions since September last year, and a significant change has been the support of the new displays SW102 and Bafang 850c and 860C.

(Left 850C  Right SW102)

In fact due to the small memory space in the older KT-LCD3 screen only the new displays are now supported for the latest firmware versions. So if you are looking to use the latest Opensource firmware from 2020 the newest displays are the only options.

I have been using the SW102 recently as I really like the small form factor and how well it fits on my bars…

Yes I know I need new grips 🙂

If i’m being honest , In bright sunlight the screen is maybe not as easy to see as the older KT-LCD3 and the buttons don’t feel quiet as nice to use, but once setup the updating is a breeze as the SW102 supports bluetooth!. Yes that’s right update from your phone without even unplugging from the cable!

The fact that Bluetooth is there also opens up the possibility to communicate with a phone app for logging and configuration in the future. That’s not there yet but simple debug logging is working so it just needs the app developing really  So if there are any keen android/ios app developers out there jump over to the forum to help out!

As well as the new screens Casainho (the main developer for the opensource firmware) has reworked the code and has done a lot of work to allow for high cadence and calibrated torque sensors as not all TSDZ2 sensors are as sensitive as others. This allows for even more fine tuning of the motor to make it feel smoother in power delivery.

Today ( May 20202), the release 1.0.0 is in Beta (Numbering scheme is a little confusing) but this has a lot of changes and features

I very much like the customisable information screens that even work well on such a small screen.


How is my bike doing any problems?

Well tough wood I have not really had any issues recently. the only issue I had early on last year was that I got water into the TSDZ2 housing due to not sealing the cable entry very well. I had to dry it out and it has been fine since. Also I has a similar water issue in my cable where I spliced it and water had got in and damaged the ground wire so that was causing some odd issues!

So I have learned that water is not your friend and if you open the motor or cut the cable make sure to seal it well afterwards.

I have re greased the main drive wheel once and I think it may be due another service but that’s a 30 min job and you don’t need to take the motor off the bike to get access which is great!.

But other than that its been flawless!

I have a new project in the pipleline to fit a TSDZ2 to a recumbent handbike to replage the existing bottom bracket/cranks, so future updates may include that work 🙂

and yes you do sit lay about 1 inch of the floor!









Hi, I am one of the trustees of Empowered people. As well as looking after this website, I am also an ebike builder, modifier, hacker, and general bike mechanic. I have been involved with the Charity since 2015 and participate in as many rides as I can with my wife Catherine on the 'Bike Train' if you look around the website you are sure to find me in the background somewhere.

18 comments on “Experimenting with the TongSheng TSDZ2 Mid drive system Part 4

  1. Awesome, fantastic update! Mine is still going strong. Who you using for supplies now? The eMTB also sounds an amazing feature, I’ve still not flashed.


    • Neil Perry @ Empowered People

      I have been using pswpower for all parts they have in stock. They are great on prices and also hold a lot of stock in Germany, so includes import tax for UK and ships usually within a week. Unfortunately eMTB has been dropped on the latest firmware as has torque only and cadence only modes. So I will keep the v0.20.0beta1 firmware for the future for when we have more specific build needs.


      • Ideal I’m going to order another today from pswpower going to convert a second spare hardtail. I’d like to find a suitable full suspension due to my knee playing up going downhill, up is not too bad (need tkr on the right leg). However it seems a minefield for frames so going to get the motor and have a play with the hardtail. Build number 2 for me. Going to flash too. Also as I will be going up hills a lot and mud so want torque not speed, should I go for the brass gear too? Awesome blog as always. Thanks Phil


      • Neil Perry @ Empowered People

        Have you considered a suspension seatpost on the hardtail? May make all the difference for your knee? Also I haven’t yet needed to switch to a brass gear on any of the tsdz2’s I have setup. Infact none have needed new blue gears yet. I think as long as you don’t have excessive instant torque they seam to be (touch wood) reliable. I think open source helps for this too with a more controlled startup torque.

        Liked by 1 person

      • Neil Perry @ Empowered People

        EMTB mode is back! And works great see..


  2. Yes got the suspension post and comfy saddle they defo help. So now I have the wifes new battery (will send a picture as these are awesome for awkward frames especially womens bikes) I’m going to buy another TS motor and convert the spare hardtail, should be helpful for my knee and I still go my normal bike for good days. I’m defo going to play with the firmware on this one whoooohooo.


  3. malcolm yates

    Hi Neil, I have recently purchased a rather cheap Carbon full suspension frame to which I shall install either a
    Baufang or Tongsheng Mid Motor. Can you inform me whether the Tongsheng motor will fit due to the extra thickness of the Bottom Bracket construction. I think there may a problem due to the limited space between the crank bearing and motor housing. Do you know if the Baufang mid drive would be more suitable.
    Regards:Malcolm Yates


    • Neil Perry @ Empowered People

      Hi Malcolm. It’s very unlikely you will be able to fit either a bafang or tonsheng to a carbon frame. As you say the bottom brackets are usually much thinker by design and so there is nowhere near enough room to slide the motor in. You only have about 10-15mm space any more and it won’t fit. I have two carbon frames I would also like to use but cannot unfortunately.


  4. Hi,
    I have a question.
    How do you get the full 750Watt out of the the motor if it’s a 500/750Watt motor?


    • Hi Phil, it all depends on the Firmware you are running, many stock TSDZ2 motors are restricted to a maximum Current ( and therefore wattage) by the firmware used. To fully unlock the motors full potential I recommend you look at the opensource Firmware. The latest build that works with all stock hardware is available here and I recommend it. I use it myself and I can get the full 750w if I want.


      • Thanks for the info.
        It looks quite complicated as I’m not familiar with this kind of thing also I use a Macbook so would the firmware run on Mac?

        Can you not just increase the max current on the display from the factory set 16amp ?

        Also can you advise what the factory set wattage for the 500\750w motor with a 48v 17ah battery and how can it be advertised as a 750w if it doesn’t provide 750w as standard?


      • Neil Perry @ Empowered People

        The standard firmware sets the max current based on the version you buy. So if you buy it advertised at 750w then as long as your battery can deliver 16A at 48v then it will deliver the full power. And yes you set the level on the screen. The stock firmware is good. And the best place to start if you are not technically minded. I have to admit I haven’t tried to run the osf java tool on a Mac , but I think others have so one to ask on the forums if you go down that path and want more options like faster cadence or smoother power delivery.


    • Getting the full power one may do by the settings in the open-source firmware.
      However, the real problem is heat. One cannot run the motor on 750 W for a long time.

      Please have a look at this page, where I show the power. When climbing a hill, the motor needs to use less power to avoid overheating.

      So the real question: How to get better cooling?


  5. Hi Neil, do you know if it is possible to downgrade (yes, you read that right!) a Tongsheng 500W 48V system to 250W, in firmware – to enjoy the torque benefits of 48V but at 250W road legal disspiation? Thanks – Rob


    • Neil Perry @ Empowered People

      Hi Rob, yes indeed if you stick with stock firmware you can reduce the max amps the motor can draw and so limiting power. Default is 16A for a 500w kit but you can lower this as needed. is a good guide of the default screen and controls. If you go down the open source root then there is a ‘street mode’ that limits to 250W 25kph which you can switch in/off easily if needed. However what you find is even when running at 750w as long as you stay in lower assist levels you generally are only using 100-200w on the flat the extra power is really to help on the steeper hills 250w feels very underpowered on steep hills. I hope that helps.

      Liked by 1 person

  6. Hi Neil, do you know if it is possible to downgrade (yes, you read that right!) a Tongsheng 500W 48V system to 250W, in firmware – to enjoy the torque benefits of 48V but at 250W road legal dissipation? Thanks – Rob


    • Jim Mumford

      Set it to street mode. Have street mode set to max speed that you want and max watts. Like 15 km/h and 250 max watts.


  7. hi guys, I am new to this fantastic ebike world 🙂 . is it possible to increase Tongsheng TSDZ2 (4000 rpm 36Volts 18 amps) engine power from 250w to 350w only acting on the display? I mean , increasing the maximum current from 16Amps to higher. OR do I need to changing the firmware?thanks


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