People tend to recommend what they have if they like what they have. The less experience usually the more dogmatic the recommendation. I'm not making a recommendation, that is a decision you have to make weighing pros and cons according to your preferences and your bike characteristics but as I have noted before I own, have installed, and ridden the Tongsheng mid drive, both front and rear geared hub motors and own and extensively ridden a Yamaha PW-SE mid drive gravel bike so I have that breadth of experience . If cost is a consideration you can get a Tongsheng TSDZ2 48v 750w with a nice small display for $415 (without the battery) from ecocycles. I bought the 36v 500w version from them, they are based in Tennessee, shipped quickly and answered a post purchase question quickly and comprehensively. I saw this '17 comparison review between the BBS02 and Tongsheng 500w, it sounds like a balanced review from someone not trying to push their opinion - why anyone would want to do that is beyond me but it is a common practice especially on anonymous forums.
Hi, I was made aware of a new offering over at BMSBattery today: "SDZ2 Torque Sensor Central Motor". https://bmsbattery.com/home/803-sdz2-torque-sensor-central-motor.html Seems like a an attractive alternative to the Bafang BBS, $50 cheaper, with torque sensor, better installation guide etc...
endless-sphere.com
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"Comparing the BBS02 with the TSDZ2
I had the BBS02 for a couple months, and then installed the TSDZ2 a few weeks ago. Here are my thoughts:
Equipment:
Motors: Bafang BBS02 750w vs Tongsheng TSDZ2 500w
Battery: 48V 11.6AH battery—same for both motors
Display: Bafang C965, Tongsheng VLCD5
Price (approx.): BBS02: $400, TSDZ2: $300
Bike: 2013 Specialized Rockhopper mountain bike, hard tail, front shocks
Testing terrain: Flat city streets of Shanghai
Summary: I prefer the Tongsheng and here’s why: It’s much smoother and blends into the normal bike riding experience, but still giving a nice boost. Although the Bafang is more powerful, it’s more like riding a moped and not as intuitive. With the BBS02, you just spin the pedals and go. With the TDSZ2 you have to apply pressure to the pedals and so it feels more natural. That said, I highly recommend both, but I prefer the TSDZ2.
Power: The BBS02 delivers 100% power as soon as you start rotating the pedals. It can be too much power if you have it on a high setting. The BBS02 can be set on levels 1-9. Typically, I started out on a 1 and increased as I started going. I typically kept mine on 4. It’s only when I wanted turbo speed that I increased it to 9. I found that I frequently adjusted the power levels, like gears, so I could keep it in control. If I had it on a high level, it could lurch unexpectedly. The TSDZ2, on the other hand, is torque-sensitive, so it detects how much pressure is put on the pedals and delivers more power the harder you pedal. The TSDZ2 delivers the power more smoothly, so I never feel the need to adjust the levels. The second I reduce pressure on the pedals, the motor slows down. The TSDZ2 has 4 levels. I usually leave mine on 3 and forget about it.
The BBS02 can be programmed using a special cable to adjust how quickly it reacts to pedal inputs. Some people insist this improves the performance and smoothness, but I haven’t tried this.
Brakes: With the BBS02, I often used the ebrakes to cut-off the motor. I would often gently squeeze the brakes, even if I was still pedaling, if I’m going near traffic or pedestrians. Then I would release the brakes and the motor would re-engage. You don’t really need ebrakes with the TSDZ2. I would just pedal more lightly and the motor turns off. It’s more intuitive. In fact, I re-installed my regular brakes instead of using ebrakes (bonus: less wires). There is no fear of lurching. It’s just smoother. Most TSDZ2 kits don’t come with ebrakes or a throttle and you don’t need it.
Gear sensor: Also, I purchased and installed a gear sensor for the BBS02. Changing gears under power can cause them to grind and get damaged. The gear sensor temporarily cuts off the motor as the gears change. The TSDZ2 doesn’t have this option, but, again, it doesn’t seem to need it. The motor cuts off very quickly when you stop pedaling or reduce pressure on the pedals. It’s like how it works normally on a bike.
Speed: The BBS02 is faster and more powerful. The speed limiter on the BBS02 can be removed (up to 99km/hr) with the C965 display. The TSDZ2 speed limit can be set up to 45km/hr (although you can set the wheel size to smaller than actual to bypass this, although the speedometer will not be accurate).
Also, I have found it difficult to get past 40km/hr on flats with the TSDZ2. I think that is because the assist cuts out beyond a certain level of RPM. A larger front chain ring would help if speed is what you need. The default chain ring is 42T. There is also a setting for “power adjustment”, which may help if I increase it.
With the BBS02, pedaling is just for looks. You don’t put much pressure on the pedals. However, the power is great. The BBS02 has great torque and you can fly off the starting line. With the TSDZ2, you will put in slightly more effort. But let’s be clear, it’s still a powerful electric motor and with not much effort, you can get quickly up to top speed.
Throttle: Throttle is available for both, but it’s unnecessary with the TSDZ2. I didn’t use my throttle either with the BBS02. I preferred to engage the pedals. I found it uncomfortable using the throttle exclusively, since you are putting 100% of your weight on your seat. That is why ebikes need softer seats, full-suspension or seat shocks. I did use the BBS02 throttle sometimes when I didn’t have my feet in the right position and I needed to accelerate quickly.
Display: The Tongsheng VLCD5 display is big. Slightly too big. I wish it were smaller. Although it has a USB port. I ordered the smaller XH18 display which fits on the left handle.
Bafang has a range of displays that are good size (about the size of a deck of cards).
Build Quality: The Tongsheng seems like a nicer build quality. Both drives are solid. The Tongsheng is a little lighter than the Bafang (but also less powerful). The chain ring on the BBS02 seems cheap and people often replace them. The chain ring protector on the BBS02 is plastic and the one on the TSDZ2 is metal.
Noise: The Tongsheng is quieter. While the BBS02 is quiet, there is still a humming sound. I can barely hear the TSDZ2.
Battery usage: I didn’t really test it scientifically, but the TSDZ2 seems to last much longer. Which makes sense, since it has a lower wattage and it doesn’t deliver quite as much power.
Installation: Basically, the same. However, if you don’t have to install ebrakes or a gear sensor, then that saves time. I have not done much bike maintenance before this, so it took me a while, but it was still easy to figure out. I needed to go to the bike shop to have them help me remove the bottom bracket since I didn’t have the right tools for that.
Community: The Bafang products are more popular and have been widely used, tested, and customized. There are more tutorials, information and guides by far than for Tongsheng products.
Bottom line:
I recommend the TSDZ2 if you want an electric motor to assist you, but still retain the intuitive feel of riding the bike. It’s much better for a novice rider or someone who isn’t comfortable dealing with the complexity of controlling the motor.
I recommend the BBS02 if you value high speed and power and don’t mind giving up the bike-like feel. Or upgrade to the BBSHD for even more power."
