Tongsheng TSDZ2 Mid-Drive Kit
The budget mid-drive with a real torque sensor. The TSDZ2 reads how hard you pedal — not just that you're pedaling — so it feels natural and intuitive in a way most cheap kits never do.
What sets the TSDZ2 apart from a Bafang BBS kit is its built-in torque sensor. Cadence-only systems give you a fixed jolt of power the moment the pedals turn; the TSDZ2 meters assist to your pedaling effort, so it feels like a high-end factory e-bike — smooth, proportional, and easy on your drivetrain. For touring, light trail, and anyone who wants a bike that still feels like a bike, that's a big deal at this price.
The trade-offs: it makes less raw power than a BBSHD (figure ~80 Nm and a sensible 250–750W), and the stock firmware is merely okay. The enthusiast move is the open-source firmware (OSF), which unlocks far better assist tuning and motor protection — but it voids any warranty and takes some tinkering. It bolts to a standard 68–73 mm bottom bracket like the Bafang kits.
Where to buy
Two paths — match your spend to the build. Quality picks last longer and come with real support; affordable picks get you rolling for less. Always confirm fitment, voltage, and connectors for your bike first.
Quality picks
Affordable picks
Affiliate disclosure: some supplier links above are affiliate links and may earn us a small commission at no extra cost to you. It never affects which parts we list or how we rank them.
Pro tips from our test team
- The torque sensor is the whole point — buy this over a cadence-only kit if natural feel matters.
- Open-source firmware (OSF) dramatically improves tuning, but it voids the warranty — go in knowing that.
- Keep cadence up on climbs; like all mid-drives it puts torque through your chain and gears.