Turning your bike into an e-bike comes down to a few things: the drive type, how much weight you add, whether the assistance is torque-sensing (natural) or cadence-based, how much chainline offset the motor introduces, and whether it actually fits your frame — MTB, full-suspension or carbon. Here's an honest side-by-side of the main kits on the market.
Specs from manufacturer and independent sources, cross-checked (2026). Always confirm current figures before buying.
| Conversion kit | Weight | Torque | Min chainring (stock) | MTB | Full-susp. | Carbon frame | |||
|---|---|---|---|---|---|---|---|---|---|
| LIGHTEST Lightest mid-driveMid-drive · Italy 🇮🇹 · doesn't replace the BB | 1.75 kg (motor) | up to 120 Nm (70–90 legal · 120 peak) | Yes | +2.5 mmkeeps the original chainline | ≈ noneSymmetricnatural, centred stance (~175 mm) | 32Tkeep your own ring — down to 32T | ✓5 mounts · BSA & Pressfit | ✓dedicated bracket | ✓load spread away from the BB |
| CYC PhotonMid-drive · Hong Kong · replaces the BB | ~3.3 kg (motor) | 110 Nm | Yes | ~+5 mmchainline set by BB width | +25–30 mmAsymmetricright pedal sits further out | 34–36TCYC rings | ✓threaded BSA needed | △verify shock/linkage clearance | △not rated; high BB torque — ask maker |
| TongSheng TSDZ2Mid-drive · China · replaces the BB | ~3.6 kg (motor) | 80 Nm | Yes | ~+2–3 mmchainring pushed outward | +40 mmAsymmetricpedals shifted right of centre | 42Tstock offset ring | ✓threaded BSA; tight on Boost | △needs a chainstay bridge — often custom | ✗often won't fit; not rated for carbon |
| Bafang BBS02Mid-drive · China · replaces the BB | ~4.3 kg (motor) | ~80 Nm (nom.; "120" is peak) | No (cadence) | ~+5 mmneeds an offset chainring | +10–15 mmAsymmetricright pedal juts out | 44Tno smaller in stock | ✓threaded BSA; check clearance | △press-fit BBs & travel issues | ✗not rated for carbon BB — check maker |
| Bafang BBSHDMid-drive · China · replaces the BB | ~5.8 kg (motor) | 160 Nm | No (cadence) | ~+5 mmneeds an offset chainring | +20–25 mmWideroughly centred | 46Tno smaller in stock | ✓threaded BSA; check clearance | △press-fit, clearance & battery fit | ✗not recommended on carbon |
| Pendix eDrive500Mid-drive · Germany 🇩🇪 · left-side unit | ~4 kg (motor)drive unit, battery excluded | 65 Nm | Yes | Lowfixed 49 mm chainline | +~50 mmWidesymmetric, both sides | 38Tstandard rings | ✓threaded BSA only | △verify clearance + cable length | △metal by default; carbon = ask Pendix |
All weights are motor-only (add a battery separately) — LIGHTEST is roughly half the next-lightest mid-drive. Frame fit depends on your exact bike (bottom-bracket standard, clearances): ✓ = designed for it, △ = possible but verify first, ✗ = not recommended. The BB-replacing mid-drives (Bafang, TongSheng, CYC) generally need a threaded BSA bottom bracket and aren't rated for carbon BB shells; hub kits like Swytch and friction kits like Rubbee X don't touch the chain but trade away power and add their own limits. Bafang BBS02 (750 W) / BBSHD (1000 W) also exceed the EU 250 W / 25 km/h limit. Specs cross-checked against manufacturer manuals and independent reviews (2026).
Every other mid-drive kit adds 3.3 to 5.8 kg of motor. LIGHTEST adds 1.75 kg — about the weight of a full water bottle. Your bike still handles, climbs and lifts like a bike, not like a heavy e-bike. That's the whole point of a conversion: keep the bike you love, just make it electric.
Most mid-drives replace your bottom bracket and push the pedals wider — and often only on one side. Kits like the Bafang BBS02, TongSheng and CYC leave the right pedal further out: an asymmetric stance. Riders on forums often link a wide, off-centre stance to knee strain and discomfort. LIGHTEST doesn't replace the bottom bracket, so both pedals stay exactly where they were — centred and symmetric. No wide-legged, lopsided pedalling.
Mid-drive (at the pedals) gives the most natural feel and best climbing, using your bike's gears. Hub motors are simpler but heavier at one wheel. Friction drives press on the tyre — easy on/off, but limited power and traction.
The single biggest factor in whether your bike still feels like your bike. Heavy kits turn a nimble bike into a tank. LIGHTEST is the lightest mid-drive by a wide margin.
A torque sensor matches assistance to how hard you pedal — smooth and natural, like a Bosch or Shimano e-bike. Cadence-only kits (most Bafang) surge on and off. LIGHTEST, CYC, TongSheng and Pendix are torque-sensing.
The chainline is where your chainring sits relative to the rear gears. A mid-drive that replaces your bottom bracket pushes the chainring outward, forcing a special offset chainring and fussier shifting. LIGHTEST doesn't replace the BB and keeps the original chainline — just +2.5 mm — so your gears shift like before.
Q-factor is how far apart your two pedals sit — the width of your pedalling stance. A motor that replaces the bottom bracket pushes the pedals wider; riders on forums link this "wide stance" to knee strain. Symmetry matters too: some kits widen only the drive side, so your pedals are no longer centred on the bike and one leg sits further out. LIGHTEST keeps a natural, centred stance (~175 mm) — no widening.
Most kits need a specific bottom-bracket standard and can struggle on full-suspension or carbon frames — a BB-clamping mid-drive generally isn't rated for a carbon shell. LIGHTEST anchors away from the BB and spreads the load, so it fits MTB, full-suspension and carbon.
In the EU an e-bike must be 250 W / 25 km/h. High-power kits (Bafang 750–1000 W) are fun off-road but aren't street-legal as sold. Check your country's rules before buying.
LIGHTEST by Bikee Bike is the lightest mid-drive conversion kit: the motor weighs just 1.75 kg — roughly half the next-lightest mid-drives (CYC Photon ~3.3 kg, TongSheng TSDZ2 ~3.6 kg, Bafang BBS02 ~4.3 kg). A few front-hub or friction kits (Swytch, Rubbee) reach a similar system weight, but they aren't mid-drive and deliver far less torque and a less natural ride.
The torque-sensing mid-drives are LIGHTEST, CYC Photon, TongSheng TSDZ2 and Pendix eDrive. Among them LIGHTEST is by far the lightest (1.75 kg vs 3.3–7 kg) and is designed and assembled in Italy. Bafang BBS02/BBSHD use a cadence sensor, so assistance feels less natural.
Kits range from about €350 (budget mid-drive like TongSheng, motor only) to €1,490 (premium German Pendix). Front-hub kits like Swytch are around €600. LIGHTEST starts from €800 and includes the lightest mid-drive motor on the market, made in Italy.
A mid-drive sits at the bottom bracket and drives the bike's own chain: better balance, climbing and a more natural feel. A hub kit puts the motor in a wheel — simpler and cheaper, but heavier at one end and weaker on hills. For the closest feel to a factory e-bike with the least added weight, a light mid-drive like LIGHTEST (1.75 kg) is the strongest option.
Yes, if you already have a bike you like: a kit is far cheaper than a new e-bike and keeps the frame, fit and feel you know. Look for light, torque-sensing, reversible and legal. LIGHTEST is built around exactly those priorities: 1.75 kg, 120 Nm torque-sensing, removable in 5 minutes.