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Bosch eBike motors explained: smart system, system 2 and drive units

How to tell a Bosch smart system bike from Bosch eBike system 2, what separates Active Line Plus, Performance Line, CX and SX, and what an owner vs a Bosch dealer can do.

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Bosch makes mid-drive motors, which it calls drive units, along with batteries, displays and apps that many bike brands build into their e-bikes. Bosch currently sells two separate systems: the smart system, launched in 2021, and Bosch eBike system 2, launched in 2013 (Bosch overview). Knowing which one you have, and which drive unit, tells you which parts fit and what a dealer needs to do.

How to tell which one you have

  • The app. Smart system bikes connect to the eBike Flow app, and a display is optional for that. Bosch eBike system 2 needs its display to connect to the eBike Connect app (Bosch overview).
  • The display. Bosch eBike system 2 uses Purion, Intuvia, Kiox or Nyon displays (Bosch eBike system 2). Smart system displays include Kiox 300, Kiox 400C, Kiox 500, Purion 200 and Purion 400 (Performance Line CX), and some bikes use an LED Remote (smart system).
  • The battery. Tern says you can tell the two apart by where the charge lights sit on the battery (Tern on Bosch systems).
  • The drive unit code. Bosch gives each drive unit a code starting with BDU, and your bike's spec sheet or manual usually lists it. The codes below show which system each belongs to.

Models and what's different

These are the figures Bosch publishes on its US and international product pages. Your bike maker can set some limits lower.

  • Active Line Plus. On the smart system, the BDU344Y gives 60 Nm, up to 600 W and up to 340% support, with assist to 20 mph. The earlier smart system BDU334Y gives 50 Nm. On Bosch eBike system 2, the BDU350 gives 50 Nm and 415 W (Active Line Plus).
  • Performance Line. The smart system BDU346Y and BDU336Y give 75 Nm and 600 W. The system 2 BDU365 gives 65 Nm (Performance Line).
  • Performance Line CX. The current smart system BDU384Y (Gen 5) is Bosch's eMTB unit. Bosch lists up to 120 Nm and 750 W, notes that torque can vary with the shifting system, and says the bike maker can cap torque at the factory setting. The Bosch eBike system 2 version is the BDU450CX (Performance Line CX).
  • Performance Line SX. The BDU314Y is a light smart system unit for slim eMTB, gravel and urban bikes. Bosch lists 60 Nm, up to 600 W and about 2 kg (Performance Line SX).
  • Other lines. Bosch eBike system 2 also includes Active Line, Cargo Line, Performance Line Sport and Performance Line Speed (Bosch eBike system 2). Bosch has also announced the Hub Line, its first hub motor (Bosch overview).

Smart system or eBike system 2

  • Parts don't mix. Tern explains that components, including batteries and chargers, only work within their own system. If you want a second battery or charger, buy one for your system (Tern on Bosch systems).
  • Phone and updates. Many smart system features run through the phone over Bluetooth, and the system takes updates over the air. Some extras need a ConnectModule and a Flow+ subscription. Bosch eBike system 2 does not need phone pairing (Tern on Bosch systems).
  • Riding modes. In the eBike Flow app you can adjust riding modes within the limits the bike maker set. Bosch warns that higher support values can increase wear and reduce range (Performance Line CX).

What this means for repair

What an owner can do:

What needs a Bosch dealer:

  • Diagnosis and updates. Dealers use the Bosch DiagnosticTool to read out eBike information, load software updates, make adjustments and print a diagnosis report on the condition of Bosch parts. They can also run a full battery check with the CapacityTester (Bosch dealer service).
  • Repairs. Bosch's Kiox manual says to have repairs done only by a certified bicycle dealer, and to contact the dealer when a code stays after a restart (Kiox manual).
  • First inspection. Bosch suggests one after about 4 weeks or 300 km (Bosch dealer service).

Bosch drive units and batteries are sealed. Never open them, and never try to change the assist speed. A swollen, damaged or very hot battery needs a Bosch dealer. See battery won't charge and e-bike battery care.

Videos

Bosch E-bike Smart System explained from GuyKesTV: Explains how the Bosch smart system ties the drive unit, battery, remote and app together and how it differs from the older system.

Related pages

Sources

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