General concensus on TSDZ, ToSeven, and any similar competitors

[DBonar]

Upfront note - I'm in the US so while I'd be happy to learn about vendors I'm really looking for specifics about the state of the torque sensor mid drive motor conversion kits.

I am in the planning stage of converting an existing bike to a torque sensing mid drive ebike. USA Class 1 (20mph/32kph and limited to 750W rating). I don't have any great objection to a throttle but it also doesn't add much. 85kg rider with at most 5kg of other stuff. Gently rolling hills but my house is at the top of a 1/2 mile 10% grade so the end of every ride is tough. Ride length is planned for up to 30 miles but mostly 20 or less under very low level PAS except on the portion at the end of the ride.

My searching leads me to three options; TongSheng, ToSeven, and CYC. I am currently not interested in CYC as I am looking for a less expensive conversion to get started. The problem is that there are so many forum threads on TongSheng and ToSeven from different years (and different TongSheng models) that it is hard to get a good clear idea of the current 2025 situation regarding build quality and status of the original firmware (I'm willing to flash new firmware but I'd prefer not to have to do it). Generally TSDZ2b, TSDZ8, and DM02.

Are there any other real competitiors?

 

[matthewslack]

I doubt if any are as sophisticated as the big manufacturers like Bosch and Shimano, but your riding doesn't need that. Any 750W motor will make easy work of a 10% slope in the highest assist setting, or using throttle if the algorithm doesn't multiply rider input enough.

TSDZ8 labelled as 250W for UK has had good recent feedback here, and is somewhat cheaper than the others. You might as well try that and get riding.

 

[saneagle]

Upfront note - I'm in the US so while I'd be happy to learn about vendors I'm really looking for specifics about the state of the torque sensor mid drive motor conversion kits.

I am in the planning stage of converting an existing bike to a torque sensing mid drive ebike. USA Class 1 (20mph/32kph and limited to 750W rating). I don't have any great objection to a throttle but it also doesn't add much. 85kg rider with at most 5kg of other stuff. Gently rolling hills but my house is at the top of a 1/2 mile 10% grade so the end of every ride is tough. Ride length is planned for up to 30 miles but mostly 20 or less under very low level PAS except on the portion at the end of the ride.

My searching leads me to three options; TongSheng, ToSeven, and CYC. I am currently not interested in CYC as I am looking for a less expensive conversion to get started. The problem is that there are so many forum threads on TongSheng and ToSeven from different years (and different TongSheng models) that it is hard to get a good clear idea of the current 2025 situation regarding build quality and status of the original firmware (I'm willing to flash new firmware but I'd prefer not to have to do it). Generally TSDZ2b, TSDZ8, and DM02.

Are there any other real competitiors?

I wouldn't get any of them for a ride like that. Crank-motors are only necesserry for off-road stuff, towing or very steep long climbs and things like that. A geared hub-motor is just so much better for normal riding on the road, especially at around 20 mph. You need 48v and a 22A controller. The Q128 motor from BMSBattery is pretty good, otherwise, there are a few 750w ones from Bafang.

I have two identical bikes. one has a 48v TSDZ2, the other has a Q128 at 48v and 22A. The Q128 was pretty good at 14A, and would probably be OK for what you want. It's more powerful and faster than the crank-drive as well as being a lot more convenient, comfortable and reliable. At 22A, it absolutely blitzes it in a side-by-side comparison. I've tried all the Bafang, Bosch, TSDZ and many other crank-drives. In practical terms, there's not much difference between the Bafangs with cadence sensors and the others with torque sensors. They both have advantages and disadvantages, which comes down to preference. Some people like to control the assist, some like the assist to control how hard they have to pedal because they say that it feels more natural to have to pedal harder to go faster.

I think you'd find the TSDZ2 too weak and slow for what you want, so if you must have a TSDZ, get the TSDZ8, but the more power you put through the crank, the more all the comfort and convenience issues show themselves.

As you can see, I'm not really a fan of crank-drives. I don't see the point, except for certain types of rides and riding. There are too many disadvantages and only two advantages. the advantages being more centralised mass and generally easier to install. Disadvantages are coarsness of the ride, noise, the need to keep changing gear, reliability, expense, wear, maintenance and more.

 

[DBonar]

I respect that you are a long term member of the forum and have infinitely more experience than I do with ebikes. On the other hand it feels like you are missing the point of my bike riding.

A geared hub-motor is just so much better for normal riding on the road, especially at around 20 mph.

I really have no desire to ride around 20 mph regularly. I would actually be fine with cruising at my normal analog bike speed on flats and rolling hills. It is hard to judge what that really is as I haven't been biking since Covid and, as mentioned in the other thread, my bike currently is restricted to a maximum 38t front chain ring, but 12 - 15 mph is fine as was roughly what I was doing during Covid.

cadence sensors and the others with torque sensors. They both have advantages and disadvantages, which comes down to preference. Some people like to control the assist, some like the assist to control how hard they have to pedal because they say that it feels more natural to have to pedal harder to go faster.

As you say there is a lot of personal preference which is why your advice feels off.
I feels like you are pushing your preferences. I want a ride that feels as close as possible to an analog bike ride with the ability to boost at some points (big headwinds, long or steep hills, the end of a ride if I'm pushing to extend the length of the trip) but otherwise having the motor turned off/no assist or, at worse, using the lowest level of assist to overcome the weight of the motor and battery. Dealing with gears and having my speed tied to how hard I'm pedaling is the feeling I'm looking for.

Torque sensing, crank drive with a smallish motor and battery looks to be the best solution for an inexperienced bike mechanic. Perhaps I'm looking in the wrong places but buying a torque sensing geared rear hub motor kit isn't any cheaper than a TongSheng or ToSeven kit and will be harder to install. It might save weight but on the other hand the weight isn't distributed as well.

 

[harrys]

I want a ride that feels as close as possible to an analog bike ride with the ability to boost at some points (big headwinds, long or steep hills, the end of a ride if I'm pushing to extend the length of the trip) but otherwise having the motor turned off/no assist or, at worse, using the lowest level of assist to overcome the weight of the motor and battery. Dealing with gears and having my speed tied to how hard I'm pedaling is the feeling I'm looking for.

Torque sensing, crank drive with a smallish motor and battery looks to be the best solution for an inexperienced bike mechanic. Perhaps I'm looking in the wrong places but buying a torque sensing geared rear hub motor kit isn't any cheaper than a TongSheng or ToSeven kit and will be harder to install. It might save weight but on the other hand the weight isn't distributed as well.

I'm not aware of many torque sense DIY hub motor kits, unless you want to buy some add-ons from Grin in Vancouver, CA. They seem kind of bulky to me.

I'm in the USA, living in Illinois, but I've carted my ebikes out to South Dakota and Colorado, and down to flat Florida. My wife and I are retired and I am very happy that she likes to ride with me. We just ride for fun, around 2400 miles annually. Average speed about 12 mph, Around 20 miles. THis will be our 10 year in ebikes.

My first conversions were 500W hub motors. with 17-20A controllers. About 1000W peak on 48V. Cadence sensor bikes can be pretty numb, as far as pedal feel. This forum generally agrees that KT controllers offer the best pedal assist feel for hub motors. As a engineer, I believe the safer hub motor configuration is a rear motor. I've done 2 front drives, but it took me a few years of stable riding to believe they weren't going to fall off. Then again, a lot of that is following known standards, as well as inspection.

Our current rides are a pair of TSDZ2 mid drives, running 48V and OSF firmware. I ride the blue 10 speed because we had the same bike 50 years ago.Both bikes have over 3000 miles, but they have had their issues.


Prior to that, we put over 5000 miles each on 20" folders. Easy to throw inside my car.Gain portability, but lose on versatility, StIll OK on gravel if you're careful,


I don't like fat tire ebikes. Have owned two, They're like Hummers when you ride on bike paths. OK for riding on the street where the bigger size makes you more visible.

Will continue later.

 

[DBonar]

Your use and solutions sound pretty close to mine. How much improvement do you find with the OSF compared to the stock firmware on your TSDZ2s? I could flash the firmware if I have to but I'd prefer not and at least one place seems to have stopped selling with the OSF installed.

 

[harrys]

I did not mention the make-buy decision. If you sit around for a year or so, and follow ebike discussions, deals and clearance sales pop up. I and family members have picked up really two decent new ebikes under $300. Even without sales, you will be hard pressed to DIY a bike for less than a commercially built one in the USA. If one has the skills/knowledge to DIY an ebike, most commercial bikes under $1000 USD can be kept running.

The biggest question on either DIY or store bought is battery reliability and safety. Too complex to discuss. WIth the push for UL2271 in the USA, that helps qualify many batteries on commercial bikes.

 

[saneagle]

I want a ride that feels as close as possible to an analog bike ride with the ability to boost at some points (big headwinds, long or steep hills, the end of a ride if I'm pushing to extend the length of the trip) but otherwise having the motor turned off/no assist or, at worse, using the lowest level of assist to overcome the weight of the motor and battery. Dealing with gears and having my speed tied to how hard I'm pedaling is the feeling I'm looking for.

The type of motor - crank vs hub - has no bearing on that. How natural it feels depends on the control system for the motor. You get crap and good control systems for both, and some that feel natural and some that don't. The best control system is the one that gives the power you want with the pedal effort you want when you want it.

Contrary to popular belief, torque sensor control systems generally don't give power in proportion to how hard you pedal. They all have different algorithms, where pedal effort is only one factor. The TDZ2 has a two step power that gives a small amount when you pedal lightly and more power when you cross a threshhold of pedal effort. The amounts of power are scaled up for each assist level, so you basically get 8 levels of assistance. That's the standard firmware. I haven't tried the OSF. I don't really see the point because the standar works pretty well. The Bafang BBS** systems give you one level of power regardless of how hard you pedal, but you can add it a lot of smoothing factors with the parameter adjustment software.

 

[harrys]

If your follow my posting history, I originally thought the TSDZ2 was a POS, compared to my hubmotors. Part of that was not being used to pedalling, although I thought I was a fit ebiker. I appreciate saneagles advice to avoid the TSDZ2. It expects you to work. In any case, a lot of that is fixed with OSF firmware. I like the feel of the torque assist now, but I had to use the OSF cadence mode on my wife's bike as she doesn't feel the need to pedal hard.

The TSDZ8 is not much more money, pre-tariff anyway, and might be a better choice. I read a common complaint on the earlier models was "no assist in level 1-2". That was my complaint on my TSDZ2, so I think that's people expecting the instant power of a hubmotor, I believe the current TSDZ8 have been adjusted. There are some pioneers trying to put OSF in the TSDZ8 and I would avoid that.

If you forgo torque sensing, the Bafang BBS02B will do everything, Quick and reliable. Had one since 2016, but I like my lighter bike.

There is also the Toseven DM02, and wouldn't you know, I have one in the box. Too many things to do and still not sure where I would put it, All I know is that my unit has a working display and the motor turns. I would expect about 30% more power with it.

 

[DBonar]

Contrary to popular belief, torque sensor control systems generally don't give power in proportion to how hard you pedal. They all have different algorithms, where pedal effort is only one factor.

That makes perfect sense and matches up with the idea that most (all?) to the torque sensor kits I have seen include a magnet ring for rotational speed sensing also. On the other hand multiple levels that I can more or less control via choosing gears and adjusting how hard I pedal sounds fairly natural.

 

[DBonar]

Part of that was not being used to pedalling, although I thought I was a fit ebiker. I appreciate saneagles advice to avoid the TSDZ2. It expects you to work.

This really hits at some of my confusion with Saneagles advice and similar advice on other forums. I'm coming at this from a strict analog biking situation. With proper gearing I don't find averaging 12 mph to be all that hard on flats or rolling hills over a 10 mile distance. I'm fine with that level of work and don't really want to drop below it. Any electric conversion will add weight but hopefully I'll get into better shape also or drop a few pounds of my weight.

 

[matthewslack]

Precise proportionality is exactly what Bosch, Shimano, Yamaha and Giant torque sensor systems deliver, which is what makes them so nice to ride, and why those riders who want that experience find them so good.

But not a kit, not 750W, although the higher torque models would amply cover your needs by the sound of it.

 

[DBonar]

At the moment those motors, as nice as they are, are not in the running unless a used or clearance deal appears.

 

[saneagle]

Precise proportionality is exactly what Bosch, Shimano, Yamaha and Giant torque sensor systems deliver, which is what makes them so nice to ride, and why those riders who want that experience find them so good.

But not a kit, not 750W, although the higher torque models would amply cover your needs by the sound of it.

If they were precicely proportional, the bike would stop between pedal strokes on a steep hill and you'd get a power surge every time you pressed the pedal. It would be terrible to ride. The old 24v Panasonic was like that.