If you are looking into the market of DIY e-bike building, you probably have come across the Tonsheng TSDZ2 and Bafang BBS02 conversion kits. Both conversion kits are widely used for DIY e-bike conversions. Both conversion kits have their own strengths and weaknesses. In this post, both kits will be compared with regard to power and torque, pedal-assist, build quality, reliability, and installation. In each category, a winner will be assigned so that you will be able to find out which conversion kit will suit you best!
September 2021: Bafang has sued Tongsheng for patent infringement. Bafang has won this lawsuit, therefore the Tongsheng TSDZ2 officially can’t be sold on big platforms like Aliexpress and Amazon anymore. Because of this, it can be hard to find sellers of the Tongsheng TSDZ2 on these platforms. Sellers on Aliexpress and Amazon now don’t use the official name anymore to avoid getting their listings removed by the platforms. I have updated the links in this post to sellers that still actually sell the Tongsheng TSDZ2 on these big platforms. You can safely order from these sellers.
Tip: very extensive reviews of both conversion kits can be found on Edrivenet.com as well. I can recommend reading them if you want to find more detailed information about both conversion kits. The Bafang BBS02 review can be found here, the Tongsheng TSDZ2 review can be found here.
Power and torque
When it comes to power and torque, there is a clear winner in my opinion: The Bafang BBS02. If you compare the same power versions of both conversion kits, so for example the BBS02 750W vs the TSDZ2 750W, the BBS02 then simply is just a lot more powerful. This shouldn’t come as a surprise since the BBS02 has a 25A controller, while the Tongsheng has an 18A controller. The higher current rating will give the Bafang BBS02 a real-world maximum power of around 1300W, while the Tongsheng will only reach about 900W. This difference is also quite noticeable when riding the two different conversion kits, the Tongsheng just has a lot less punch to it.
When it comes to torque, the BBS02 is the clear winner as well. The BBS02 has a maximum torque output of 160Nm, the TSDZ2 can only output a maximum torque of 80Nm. This difference is also really noticeable when riding the bike, the BBS02 is quicker of the line and can climb hills quite a lot better. So if you really want an extremely powerful conversion kit, the BBS02 will be without a doubt the better option for you. This ofcourse doesn’t mean that the TSDZ2 motor is weak at all, it is more than powerful enough for most riders as well, 900 watt and 80Nm is still a lot, especially for ebikes. But it just isn’t quite in the same league as the BBS02.
The TSDZ2 and BBS02 fundamentally have different types of pedal assist, this makes it hard to define a clear winner in this respect. The Tongsheng TSDZ2 uses a torque-sensing type pedal-assist, this type of pedal assist measures the force that is applied to the pedals and will apply a certain amount of pedal-assist proportional to this applied force. The BBS02 does it differently with its cadence-based pedal-assist. A cadence-based pedal-assist tracks the rotation of the pedals and will apply a certain amount of pedal-assist proportional to the amount of rotations/sec (cadence).
A cadence-based pedal-assist generally is considered worse than a torque-sensing pedal assist. Torque-sensing pedal-assist often is found on expensive e-bikes, while cadence-based pedal-assist generally can be found on cheaper e-bikes. This torque-sensing feature of the Tongsheng TSDZ2 is therefore really impressive considering its affordable price point. It also is the main selling point of the Tongsheng TSDZ2, since it is the only (known brand) DIY mid-drive conversion kit that offers torque-sensing pedal-assist.
So is the torque sensing pedal-assist of the TSDZ2 better than the cadence-based pedal-assist of the BBS02? This really depends on personal preference, but most riders will probably prefer the TSDZ2 pedal-assist. If you want the most natural feeling pedal-assist, the TSDZ2 is a lot better than the BBS02. The TSDZ2 will feel like an extension of your body, while the BBS02 will feel more like a push in the back. At low speeds the TSDZ2 is also a lot more controllable, the bike won’t shoot off if you don’t want it to. All these advantages are because of the torque-sensing type pedal assist, which can sense force instead of just rotation.
The BBS02 is however better if you are more of a lazy type of rider. The BBS02 will still give a lot of assistance even when you barely apply any force to the pedals. This of course is the case because the BBS02 can’t sense how much force is applied to the pedals. So pedal rotation is sufficient to get assistance, this, therefore, allows for quite a lazy riding if you want to. This isn’t the case with the TSDZ2, if you want the maximum power output of the motor, you will have to apply quite a lot of force yourself. You therefore always have to put in some work as well (if you don’t use the optional throttle of course).
For some riders, this can be annoying, especially if you want to ride at high speeds a lot. If you want to sustain 40km/h on the Tongsheng TSDZ2, you have to apply a considerable force, to get the desired amount of power assistance. At lower speeds, this “problem” isn’t really noticeable anymore. So if you don’t want to ride at such high speeds, the pedal-assist of the TSDZ2 will be better in all regards.
In the end, I will assign the win for the best pedal-assist to the TSDZ2. The torque-sensing pedal assist provides natural assistance and makes the bike really controllable at low(er) speeds. The Torque-sensing pedal-assist simply is superior to cadence-based pedal-assist in many regards. If you are more of a lazy type of rider, however, then the BBS02 will be the better match for you. All other types of riders will probably prefer the TSDZ2’s pedal-assist.
Buy the Bafang BBS02 or TSDZ2 @Aliexpress – Global shipping
As far as build quality goes, there is a clear winner: the Bafang BBS02. The BBS02 really feels like a quality conversion kit. First of all the metal enclosure looks and feels a lot more sturdy and premium than its TSDZ2 counterpart. The paint job is also a lot nicer on the BBS02, the glossy finish looks way better than the matt finish on the TSDZ2. The BBS02 also feels better put together and has higher quality connectors and cables.
Another big difference is in the displays. The BBS02 works with a lot of nice, high-quality, good-looking displays. Whatever display you choose, you will always have a capable and nice-looking display. The TSDZ2 only works with three specific displays, all these displays look rather old-fashioned and are not high-quality. The TSDZ2’s displays also have fewer features and functions than the BBS02’s displays. So if it comes to displays, the Bafang BBS02 really has a massive advantage over the Tongsheng TSDZ2.
So, overall it’s clear that the Bafang BBS02 wins this category. The BBS02 has way better displays, connectors, cables. The BBS02 also has an enclosure that is better put together. I also think the BBS02 looks a lot more premium than the TSDZ2 with its glossy paint job.
As far as reliability goes, assigning a winner wasn’t that difficult. The Tongsheng TSDZ2 simply is more reliable than the Bafang BBS02. The reliability issues of both motors often have to do with the controllers. The controllers of the Bafang BBS02 are known to fail. I can confirm this with my own experience, as well as the many reports on the internet. Replacement controllers sometimes can be shipped out for free in the warranty period via the seller. If not, a new controller will set you back around 80-90 USD. Replacing the controller can be quite a challenge, but it is doable. Many instructions can be found on how to do this.
The Tongsheng TSDZ2 doesn’t seem to have these controller failures quite as often as the Bafang BBS02. The controllers are more reliable and replacing one is a rare occurrence. Other parts of both motors seem to be equally reliable. The gears inside the motor can fail over time, but this will only happen after many many miles. So apart from controller failures, the Bafang BBS02 and Tongsheng TSDZ2 are quite bullet-proof. Since the TSDZ2 also doesn’t have the issue of frequent controller failures it’s the clear winner here.
Both the TSDZ2 and BBS02 have very similar installation procedures. They both have to be installed in the bottom bracket frame part. The motor will slide into the frame and will be locked using a lockring. The Tongsheng TSDZ2 has an extra mounting arm that prevents the motor from sagging over time. This extra mounting arm is nice since it also prevents the motor from becoming loose. You, therefore, don’t have to tighten the lockring as often as you will have to with the BBS02, the periodic maintenance simply will be less.
This extra mounting arm does have a disadvantage. The mounting arm can cause clearance issues on some bikes. Especially if your brake cables run underneath the motor. The TSDZ2 motor tends to have some clearance issues with those cable guides. Often, those clearance issues can be fixed by removing the extra mounting arm altogether or moving some parts on the frame out of the way. So as far as out-of-the-box compatibility goes the BBS02 will win. The TSDZ2’s extra mounting mechanism is nice if you get it to fit properly though. I will assign the win to the BBS02 because of the simple installation procedure and great out-of-the-box compatibility.
Buy the BBS02 or TSDZ2 @Aliexpress – Global shipping
The Tongsheng TSDZ2 and Bafang BBS02 each have their own strengths and weaknesses. The BBS02 wins in 3/5 categories, while the TSDZ2 wins in 2/5 categories. This however doesn’t mean that the BBS02 is the clear winner here. Both conversion kits have their own uses cases and you should decide which categories are most important to you. You then should take these weighted categories into account to make your final decision. To sum things up:
The Bafang BBS02 wins in the following categories:
- Power and torque
The Tongsheng TSDZ2 wins in the following categories:
I think either the TSDZ2 or BBS02 are great conversion kits, you can’t go wrong with either of them. You should make your decision based on which categories you find most important. If you do this, I will guarantee that you won’t be disappointed with your purchase! Good luck with your DIY e-bike conversion!
If you have any questions, want to start a discussion, or need some support, please use the comment section below. I will respond to you within 24 hours.