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What happens when two of the best-selling mid-drive electric bike conversion kits go head to head? In this TSDZ2 vs BBS02 comparison I’ll take a closer look at what both kits have to offer, their differences and the pros and cons. Over the last couple of years I have installed more than a hundred Bafang mid drives, and more recently around thirty Tongsheng systems.
Both the Tongsheng TSDZ2 and the Bafang BBS02 are market leaders in mid-drive electric bike conversion kits, with the latter having a substantially larger slice of the pie. Although both motors share similarities, they’re also quite different in many ways. For this reason, they appeal to different riders. The BBS02B 750w is quite a brute, and produces loads of grunt, whereas the TSDZ2 is more refined and sedate in the way it produces power. Either way, they are amongst the best e-bike conversion kits on the market.
Bafang BBS02B
The Bafang motor is well-established, and despite some ongoing reliability issues, still offers the most bang for your buck. A BBS02 750w will kick out close to 1500w with a 52v battery fitted. This will transform your humble bicycle into a high-performance speed machine (but the 52v battery may compromise reliability). I always recommend sticking with a 48v battery, unless you are willing to shell out for replacement controllers.
| Bafang Model | Battery | Peak Power (Watts) |
|---|---|---|
| BBS02 500w 36v | 36v (42.2v x 25A) | 1055w |
| BBS02 500w 48v | 48v (54.4v x 18A) | 864w |
| BBS02 500w 52v | 52v (58.8v x 18A) | 1058w |
| BBS02 750w 48v | 48v (54.4v x 25A) | 1200w |
| BBS02 750w 52v | 52v (58.8v x 25A) | 1470w |
The pedal assist system (PAS) on the Bafang motor acts like an on/off switch. As soon as the pedals rotate a few degrees, the motor kicks in. The pedal assist on all the Bafang BBS motors can be fine-tuned with controller programming and careful selection of the 9 available power levels.
With this method of pedal assist you just have to turn the pedals to get assistance, you don’t have to put a lot of effort in. It is possible to climb a 25% gradient in a low gear with the power level set to 9. All you will be doing is spinning the pedals, the motor will be doing most of the work!
The BBS02 has a lot of potential for fine-tuning. Being able to reprogram this motor is a real bonus.
It should be noted, that compared to a normal bike the Bafang is harder to pedal when the motor is switched off. This is not so much of an issue when cycling on the flat, but if you find yourself out of battery power, pedalling up a steep hill can be practically impossible.
The BBS02 has a lot of potential for fine-tuning. Being able to reprogram this motor is a real bonus, and in some cases necessary. In my experience, the factory pedal assist settings are not very good, in particular the way the pedal assist stops and starts. Thankfully these can be changed in a matter of minutes by connecting your motor to your laptop using a Bafang USB lead and this free open-source software.
Tongsheng TSDZ2
The Tongsheng TSDZ2 has been around for a while now, and early reliability issues seem to have been resolved. It is now a very viable alternative to the Bafang BBS02.
The main difference between these two motors is the pedal assist. With the Tongsheng it is not a free ride. You are rewarded with more power only if you put the effort in.
The Tongsheng uses torque sensing pedal assist. This gives you motor assistance proportionate to how much force you are applying to the pedals. This makes for a very intuitive system right out of the box. Even using the 48v750w version**, you still have to put some degree of effort into pedalling for the motor to work. I like this, as it feels a like a Bosch motor on steroids!
| Motor | Battery | Peak Power |
|---|---|---|
| Tongsheng TSDZ2 36v (250w variant) | 36v (42.2v x 16A) | 675w |
| Tongsheng TSDZ2 48v (500w variant) | 48v (54.4v x 16A) | 870w |
The progressive surge of power you get in sport mode does make you feel like the bionic man! The motor feels more like an extension of your own cycling abilities.
If you prefer to ride at a high pedalling cadence, it is worth noting that these motors do not produce any noticeable assistance above 90 rpm. The initial burst of power fades quickly when these high cadences are reached, even though force is still being applied to the pedals.
With the motor switched off, the Tongsheng wins, hands down over the Bafang. Although there is some increased pedalling resistance, it is nowhere near as noticeable as on the BBS02.
If the BBS02 is the lazy man’s electric bike conversion kit, then the TSDZ2 is for people that don’t mind working up a bit of a sweat. Although the 500w and 750w versions are substantially quicker than their lower-powered counterparts, you still have to put in some effort to get the motor working.
The only downside with the Tongsheng motor is programming the controller. It is possible but it is not as straightforward as with the Bafang, also you are limited to only 4 different levels of assist versus the Bafang’s 9 levels.
Tongsheng does not officially sell a 750w version of the TSDZ2 – such versions have modified firmware and may be susceptible to reliability issues.
Bafang BBS02B Pros and Cons
The Bafang BBS02B is a great motor. But, like all things electric, there are potential problems to be aware of. On the whole, I would say the BBS02B is one of the best e-bike conversion kits available, but its suitability depends on your personal needs. If it’s raw power you’re after and hill-busting torque, then the BBS02B is a tough act to follow!
Pros
- The very responsive pedal assist
- 9 levels of pedal assist
- Good spare parts availability – find out where to buy Bafang parts
- Programmable
- Well established brand
- Very powerful
Cons
- Some reliability issues persist
- Pedalling resistance, when the motor is switched off
- The motor may need periodic tightening
- More expensive than the Tongsheng
- Feels more like an electric motorcycle (not a bad thing, if that is what you are looking for)
- Stock controller settings are not very intuitive
Tongsheng TSDZ2 Pros and Cons
If you’re looking for an e-assist that rewards you for the effort you put in, then the Tongsheng TSDZ2 is ideal. This motor enhances your riding ability whereas the Bafang can completely take over! The TSDZ2 is the closest thing you will get to a Bosch or Shimano Steps. And, although it’s nowhere near as refined, it’s pretty damn good for the price!
Pros
- Intuitive torque sensing system
- Easier to pedal than the Bafang when the motor is switched off
- Lighter than the Bafang
- Can provide a ‘more natural’ cycling experience
- Very efficient motor / increased battery range
- Parts availability is good – find out where to buy Tongsheng parts
- Great value
Cons
- A certain degree of pedalling effort is required to start the motor – this may not be suitable for everyone
- Programming is possible, but not as straightforward as the Bafang
- Only 4 levels of assistance
- Very limited clearance between the motor axle and bottom bracket
- The motor does not give any noticeable assistance at high pedalling cadences.
- The blue nylon primary gear can be prone to premature failure
- Although the torque sensor is generally reliable, it has been known to fail.
- Wider q-factor
Conclusion – TSDZ2 vs BBS02 Is There a Clear Winner?
Both the Bafang and Tongsheng motors are excellent in their own way, but which motor to choose really boils down to your own personal preferences.
If you want an enhanced cycling experience, with the motor feeling like an extension of your own ability, then the Tongsheng is definitely the way to go. If you have a medical condition that limits your ability to pedal hard, or you just want an e-bike that does most of the work, then the Bafang may be more suitable.
Both of these motors are great fun and will transform your riding experience! If I had to make a choice, based on my own personal experiences, then I would have to choose the Tongsheng over the Bafang. I’ve had the benefit of covering lots of miles on both motors and I just prefer the feel of the torque-sensing pedal assist. Plus, I like the neat installation and increased efficiency of the motor. I still love the Bafang though, as it just destroys hills without effort!
Where Can I Buy the Tongsheng and Bafang Motor Kits?
Both the Bafang and Tongsheng are global best-sellers in the field of e-bike conversion kits, and as such are widely available. Tongsheng availability has been limited on Aliexpress recently, due to a patent lawsuit (from Bafang). Both motor kits are still available on eBay and Amazon in most territories. I have provided links below to sellers with good feedback on all main e-commerce platforms.
Bafang BBS02B
Tongsheng TSDZ2
| Amazon |
| eBay |
| Aliexpress |
| Check the Latest Prices at ebikepricecomparison.com |
Thanks for reading, please feel free to leave a comment below – I usually respond within 24hrs
Morning Tony, I’ve been following your very interesting blog for too long and really need to make a decision so that I can return to cycling.
I’ve just purchased a s/h unused Cube Aim 2022 bike which i want to convert with the Tongsheng motor. I’m interested in the new TSDZ2B but reviews are pretty slim. So looks like I’ll have to go in blind. I have read a few comments that are still causing me hesitation, such as, “the firmware is now locked down”.
I realise that untill the population grows this might just not have attracted much interest but wondered if you could comment on this aspect and if you are likely to be reviewing this product in the near future.
At 76 I intend to stay legal, not worth risking my driving licence even if i will be working to leave perranporth in any direction. I don’t want a twist and go just yet.
Thank you,
Tony
p.s. A link to a reliable supplier for the new motor will handy 🙂
Hi Tony,
Looking at what they’ve changed in the motor, I would say it’s well worth considering. The clutch system has been changed so the motor disengages when assist isn’t used – this should drastically reduce pedalling resistance. The original ‘one-way’ bearing was a weak point and this has hopefully addressed this problem. Tongsheng have also improved the primary gear, to reduce the chance of premature failure. Looking at photos of the new internals, the new gear looks much bigger. Regarding the firmware, this is to stop third-party suppliers selling motors with increased voltage and current. Because the TSDZ2 is quite a small motor, anything much above 16 amps caused overheating issues and controller failure.
I’ve converted a few 2018 / 2019 Cube Aim Pro hardtail MTB’s. The only problem you may have is the limited clearance between the motor shaft and bottom bracket shell. The Cube has an internal cable routing sleeve on the underside of the downtube. This can interfere with motor installation – I used to have to file some of the alloy down where the cables exit near the bottom bracket.
Here is a link to a good seller on eBay: Tongsheng TSDZ2B – eBay is probably the best place to buy because of their returns policy. I you did get a lemon, it should be fairly easy to get your money back.
I’m will be reviewing the newer version, but not until the Spring. Let me know if you have any more questions.
Cheers,
Tony
Hi Tony, thank you for your thoughts and the heads up on the cable routing.
Hopefully I will have some feedback to you on the new motor in time for your review.
I understand Tongsheng trying to lockdown the firmware, I doubt I’d be looking to make changes before the warranty expired anyway. Just have to hope the stock FW suits me.
I would have liked 48v to keep the current down but im informed that 250w are only available with 36v batteries.
Thanks for the ebay link, I’ll update you when I have it here.
Cheers
Tony
Thanks, much appreciated. Hope the build goes well.
All the best,
Tony
“f you are concerned about the current e-bike laws, it is worth remembering that both the BBS02 and 500w / 750w TSDZ2 are not road legal in the UK, EU or Australia. If you do choose to use them on the road you do so at your own risk and most importantly you need to consider the potential risk to others. Please read my guide to electric bike law .”
Legally there is only one TSDZ2, labeled as “TSDZ2” in their EN15194 and CE certificates.
It’s technically all 250W nominal, the “500w” and “750w” labels are technically just marketing.
This can also be quite easily seen when trying to reproduce the maximum nominal power tests. Basically 10 minutes full throttle limited to 500w, overheats a stock 48v/500w TSDZ2 (which is 100% the same as the “750w” version).
This is no coincidence, Tongsheng on-purpose gimped cooling around the motor (by adding an air-filled void as isolation), because a slight overheat would legally keep it within the 250w nominal range, even if it could give out up-to 800w peak.
Hi, I want to install a mid-drive conversion kit on my wife’s Electra Townie i3 bike. She loves it because she is only 5 ft tall and the seat can be lowered enough to be comfortable for her. This bike has a COASTER BRAKE. I have been weary of the Bafang kits because I don’t understand if they work with coaster brake bikes. I just read the Tongsheng IS compatible with coaster brakes. Can you confirm this? Any other insights you might have for me. Much appreciated. Thanks.
Aaron
Hi Aaron,
The Bafang wouldn’t be compatible with a coaster brake because of the motor freewheel. There is a coaster brake-specific Tongsheng TSDZ2 motor – I couldn’t find one on Amazon or eBay, but there’s a US based Tongsheng supplier called Eco Cycles who may be able to get one.
Regards,
Tony
Hi
I agree that the torque sensor on the TSDZ2 is sweet.
I installed a TSDZ2 on my Trek commuter bike using Kobalt 40V batteries. It works great about 90% of the time but it occasionally loses power and gives no assist for a few minutes and then randomly comes back on. There is never any change on the controller. It still shows the battery level and looks totally normal. After a random period of a few seconds or minutes, it comes back and I get assist again. I can’t figure out any rhyme or reason to it. It happens on smooth ground too and in gentle pedaling or pushing hard. The o Lu advice I’ve gotten was to adjust the speed sensor which I’ve tried every way. If anybody has a recommendation for what to check, replace, etc or another place to get help I would be grateful.
Thanks!!
Hello Tony,
I want to install a Bafang or a Tongsheng motor on a 30kg (61.73 Lb) bike with a Nexus 7 hub.
My need is:
– To ride a 10km trip with 120m elevation gain (6.2 miles – 394 ft) without sweating at all (to meet clients!).
=> Do you think this eliminates the Tongsheng?
– Having the most comfortable gear-shifting behavior. I mean without motor a just release the pressure on the pedal during the shift, and re-apply the pressure right after. I don’t want to stop pedaling for ex.
=> What about both motors regarding that?
– Do you think a 250W motor is enough for this weight?
– Is there a risk to get more wear on the Nexus 7 with one or the other? How to mitigate that?
Thanks a lot :).
Hi,
I would definitely go for the Bafang on a heavy bike, preferably the BBS02B 48v variant. To cover that distance and elevation gain quickly and without sweating, you’re going to be looking at the 500w or 750w version. I’ve installed a BBS02B 750w on several bikes with Nexus 7 and Nexus 8 without any long-term issues. You will need a gearshift sensor, and you’ll need a USB programming lead and free software. When using a geared hub you will want to dial back the pedal assist ‘start current’ to 5% – it’s not advisable to use a throttle with a geared hub. Also, I would limit the ‘max current’ to 18 or 20A.
I hope this helps, let me know if you have any more questions.
Regards,
Tony
Hello Tony,
Thank you so much for the quality and the level of detail of your answer!
At this point this is enough to remove the last questions I had.
I will come back in case I have more questions.
Thanks again :)!
You’re welcome👍
Bonjour,
Je cherche à installer un moteur central sur un beach cruiser à rétropédalage. Le BBS02 n’est pas compatible du fait de sa roue libre, qu’en est-il du Tongsheng ?
Bonjour,
Il existe une version frein à rétropédalage du Tongsheng qui conviendrait. Voici le lien:Tongsheng TSDZ2 Coaster Brake Version
Salutations,
Tony
Does the engine TSDZ2 coaster brake charge the battery while braking (regeneration) Most of my rides would be on a steep, fast and long incline (3km, 10+%), where the use of the brakes is necessary.
Is it possible to adjust the regeneration power?
Unfortunately, the TSDZ2 does not have a regenerative braking function.
Hola amigo.
Gracias por los artículos, son muy claros.
En el del motor Tongsheng no he visto que se pueda comentar y por eso te expongo mi duda aquí.
Hablas en ese post de que el Tongsheng admite platos estándar 110 BCD y quería saber si han de tener alguna caratcterística especial o vale cualquiera.
En mi caso, he montado un Tongsheng 750 en mi Handbike deportiva y hago rutas por etapas sobre los 60 km. La handbike solo dispone de los brazos, no hay peso del cuerpo ni la fuerza de las piernas y el perdaleo es paralelo y más empujando y tirando que pisando hacia abajo.
El caso es que un plato de 42 t se hace casi imposible de mover en cuestas arriba con cualquier desarrollo ded piñones que le metas (hablo de ir sin batería que es lo que me preocupa) por lo que mi combinación ideal es un plato de 32 dientes (disponible en 110 BCD) con un cassette de nueve velocidades 11-50 t. (tengo un cambio Sram X0 de 9v)
Quería confirmar que lo del plato es posible y mantiene una buiena línea de cadena o no ser altera la que trae con los platos específicos y si puedes recomendarme algún plato y cassete de las características indicadas.
Muchas gracias
Hola,
Un plato de 32t 110BCD debería funcionar bien, aunque puede haber un compromiso en la calidad del cambio (particularmente en las marchas bajas). He instalado platos de 34t y 36t en el TSDZ2 en el pasado sin mayores problemas, por lo que definitivamente valdría la pena intentarlo. Por favor, avíseme cómo van las cosas.
Saludos Tony
First, great articles, best source of information I have found 🙂
I’m about to order a BBS02 750W with batteries from the shop in your links, but the pre-order service is not very good. So, two questions:
1. In your experience, is Bestebikes on AliExpress thrustworthy? Or where do you order from (I’m in Norway, so no EU warehouse, must send from China….)? Risk of being cheated is more important than price.
2. I cant decide between the batteries, choices are no-brand 48v13ah, no-brand 48v17ah or samsung 52v17,5ah. I will reprogram according to your advices. My previous experience buying batteries on AliExpress is that there are a lot of counterfeit premium batteries samsung/LG/etc sold so I might as well just buy the smalles, cheapest pack as it is enough for my daily 8 miles commute?
Thank you in advance!
Kjetil
Hi Kjetil,
I used to buy a lot of kits direct from China from Bestebikes and they used to deliver to the UK in about 10 days, but that was before Covid. I would imagine delivery will take more like 3-4 weeks, especially for the battery as that has to be sent by a different method. Batteries used to take 21-28 days to get to me from China. I’ve never had any major problems with their kits.
Regarding battery, if you’re only doing an 8 mile commute, the 48v 13Ah should be adequate. The last Bafang BBS02B purchased from Bestebikes with their 48v 13Ah battery was getting 30-35 miles from a charge (using mixed assist).
If you wanted to buy the battery separately, UnitPackPower are the best supplier on Aliexpress – I’ve brought around 100 batteries from them in the past and not had a single issue and their customer service is excellent. Here is the link to their Aliexpress battery store.
Regards,
Tony
Hello,
I just had the BBS02B 48V 750W installed on my Bacchetta A26 two wheel SWB recumbent bike. I went with the 48V 17.5 amp battery. Balance is a major issue with a two wheel recumbent when starting off or going slow. Without the motor, I would gear to the largest cog, clip in with one foot and push off to get up to speed for maintaining balance. To prevent damage to the motor should I use the throttle to start or just clip in with one foot using say PAS 2 and push off. With the extra weight of the motor and battery, I don’t think starting with the unit off a good option. I’m using the DPC-18 display with 9 PAS levels. What do you think?
Thank you,
L.P.
Hi Larry,
Using the throttle to start will definitely make things a bit easier. I would recommend getting a Bafang programming lead and re-configuring the ‘start current’ on the throttle setting to around 10% and also making sure you are in a fairly low gear (particularly if it’s a hill start) to avoid any unnecessary load on the motor.
All the best,
Tony
Hi Tony
We are starting to import electric bikes into Australia, most are commuter 250w hub drive but some will be a high spec full suspension MTB, most will be 250w Bafang M400 but a small QTY was to be M600 with 48v 14AH battery in the downtube, however we have just found out that the M600 had nylon cogs replaced with steel because of high failures, which fixed the problem but it is now quite noisy.
1. Do you have any experience with the M600 with & without nylon cogs
2. What alternatives would you suggest in good quality Chinese motors for a fair bit of extra power over M400 250w?
3. Where are you located? We are in Melbourne Australia.
4. Also Shimano Deore is long delivery at present, how do you think Alivio compares?
Thankyou for you balanced view of Bagang vs Tongsheng above, if you could reply promptly I would be very grateful.
Regards
Russell Davidson
MD One Bike
Hi Russell,
Apologies for the delay in getting back to you. If you can send me over an email to: [email protected] I can answer your questions in more detail.
I’m based in Cornwall in the South West UK.
Regarding Alivio vs Deore, I use an Alivio rear derailleur on my touring bike and it still works a treat even after 6000 miles.
Regards,
Tony
La verdad es que el sensor de par puede resultar en un pedaleo asistido más natural pero a veces puede resultar en una falta de ayuda cuanto más se necesita, me refiero a que con un sensor de par el motor da “más” cuando nosotros damos “más” pero puede ser que nosotros no estemos para dar “más” pero si requeriramos del motor su máxima potencia, para esto sería mejor el PAS del Bafang.
Gracias por tu comentario, estoy totalmente de acuerdo contigo en este punto. Además, es muy fácil volver a configurar los ajustes de asistencia de pedal utilizando el software Bafang para hacer que la asistencia de pedal sea muy suave y progresiva simplemente modificando algunos de los parámetros básicos.
Regrets, my Spanish isn’t up to a coherent reply. But in English I can write that the Tong Sheng PAS in combination with a thumb throttle can really help dial in your power need. It took me a bit of practice to use the thumb throttle while pedalling and not produce a surge in power greater than I desired but I now use this technique more than bumping up to the next assist level.
Hi Guy,
Thanks for sharing, much appreciated.
All the best,
Tony