In this Tongsheng TSDZ2 review I will go over the Benefits of this particular electric bike conversion kit. In this post I will be reviewing the 250w version – this is the only variant I can recommend for road legal use in the UK, Europe and Australia. At the bottom of this post there is a link to a price comparison table for the Tongsheng and Bafang motor kits.
I will be reviewing the more powerful variants later (specifically for the US market).
Tongsheng have been manufacturing plug and play mid-drive electric bike conversion kits for a few years now, and although not as popular as the Bafang mid drive conversion kits, Tongsheng are steadily increasing in popularity Earlier versions did have some reliability issues, but as with the Bafang, a lot of these seemed to have been ironed out now.
I have personally installed approximately twenty of these kits on to various bikes, ranging from low-step commuter bikes through to full-suspension mountain bikes.
The main criteria for installation is similar to the Bafang, the main difference being is that Tongsheng offers the TSDZ2 in 68mm and 73mm bottom bracket variants As with the Bafang, the size of the bike’s bottom bracket needs to be a standard 68mm-73mm wide bottom bracket with an inside diameter of approximately 33.5mm. It must be noted that these kits are not intended to be installed on bikes that use a pressed-fit bottom bracket, as the dimensions are not compatible with the motor unit. There can be a way around this if a special shim and mounting plate are machined by a professional engineer.
If your bike has an eccentric bottom bracket as fitted to tandems and bike’s with internally geared hubs like the Shimano Nexus, installation is still possible, but may be problematic.
The motor comes as a kit with the following key components:
- The motor unit with integrated controller
- LCD Display – VLCD5 or XH18
- Wiring loom
- Inner and outer lock-nuts
- Chainring 42T
- Speed sensor and wheel magnet
- A bag of various Allen bolts and screws
- Installation tool / spanner
Please read my separate article on electric bike law here.
The installation of this motor is the same as with the Bafang Mid Drive. One of the really useful things about this kit, is unlike the Bafang kit, the Tongsheng kit comes with an installation spanner. If you are looking for a nice easy conversion to do yourself, but you have little or no experience with bicycle mechanics or using tools, I would not recommend this kit. I will write a separate post detailing the installation process with photos, but the installation will need to be carried out by someone who is fairly competent. Removing the bottom bracket can be a right pain, and you will require a lot of patience!
The installation video below shows the installation process, although it looks like they loosened the bottom bracket beforehand!
These motors have an internal torque sensor, and give assistance proportionate to the amount of force applied to the pedals (much like the Bosch system) . The upshot of this is, that you will need to make a certain degree of effort in order for the motor to work, unlike the Bafang system, which will give assistance as soon as the pedals are rotated.
These motors can be reprogrammed, but it is nowhere where near as straightforward as the Bafang – click here for further information on programming the Tongesheng motor. PLEASE NOTE: Reprogramming the 250w motor to any higher than 15A and 15.5mph (25km/h) will make it illegal for road use in the UK/UE/AU.
Like the Bafang, this motor works through a series of gears, and drives the rear wheel directly through a single front chainring. The benefit of this is the motor is using the bike’s gear ratios for maximum efficiency and torque. Also, like the Bafang motor, gear selection is important when pulling away or hill climbing.
I have supplied and installed quite a few Tongsheng TSDZ2 motors and to date, and I have only had one issue reported, and this was on a bike being used for serious off-road riding.
- Although I haven’t personally had any issues with the Tongsheng, they can and do occur from time to time.
- The torque sensor has been known to fail – although this seems rare and a replacement is not overly expensive.
- Controller failure is also much rarer now than it was a few years ago, a replacement controller is much cheaper than a Bafang controller.
- The blue nylon reduction gear can be prone to premature wear, although this seems to hinge on how hard the bike is being ridden and is unlikely to be a problem on commuter and leisure bike.
- Because of the way the power is delivered there doesn’t appear to be much of an increased risk of wear and tear on the bike chain and gear components.
The general feel is one of an enhanced cycling experience, you still have to put in an effort but it makes you feel like you have bionic legs, which is great fun!
Riding a Tongsheng powered Electric Bike
The first installation I did using a Tongsheng motor was on a Voodoo hardtail mountain bike, and I must say I was pleasantly surprised. The 250w motor is very quiet and smooth, and you have up to 4 levels of pedal assist to choose from.
The torque sensing pedal assist works really well, and having ridden Bosch equipped bikes, I would say the power delivery is very similar, although it does not have the added cadence sensor of the Bosch motor. The general feel is one of an enhanced cycling experience, you still have to put in an effort but it makes you feel like you have bionic legs, which is great fun!
Another big plus point is that unlike the Bafang motor, the pedalling resistance when this motor is switched off is barely noticeable.
As with the Bafang you will be limited to a single chainring, but Tongsheng offer a 42T as standard, which is much better gearing than the 44T minimum offered by Bafang. There is also a 104BCD and 130BCD chainring adapter available allowing you to use a standard chainring of your choice.
As this bike uses a torque sensing system, brakes with cut-off sensors are not required, reducing the need for more untidy external wires.
This motor is also 30% lighter than the Bafang equivalent, and the overall look is a little more discreet – below is a photo of an Orange full suspension mountain bike that a customer converted. He also owns a Haibike and actually prefers the Tongsheng conversion!
As with the Bafang, the Tongsheng will not be for everyone. Installation can be challenging and the motor may need periodic maintenance. It is nonetheless an excellent option, and the end result will be a bike that looks more like a factory produced ebike.
The torque sensing system may not suit everyone, as you will still need to put a fair amount of effort in for the pedal assist to work. But for me personally, I loved the way it provides assistance. My only real complaint, is that I generally ride my bike at a higher cadence of between 80-100rpm, and this motor does not seem to provide much assistance beyond 90rpm.
This motor is also a little cheaper than the Bafang, making it excellent value for money.
If you are comfortable with your ability to install it, and you have an appropriate donor bike, then as long as you can live with some of the compromises, this is an excellent electric bike conversion option and an excellent alternative to the Bafang.
In my next post I will be doing a head-to-head Tongsheng vs Bafang comparison
Value for Money9.0/10
Ease of Installation6.0/10
- Excellent Value for Money
- Very efficient
- Torque Sensing pedal assist
- Very neat installation
- Great performance
- Can be difficult to install for the inexperienced
- Torque sensing assist is not for everyone
- Assist stops working at high pedalling rpm
- Reliability issues reported when subject to hard off-road use.