Bosch Tuning: Guide for BES2, BES3, Smart System, Gen4, Gen5, BDU & rim magnet
Bosch e-bikes cannot be reliably identified solely by terms like CX, Gen4, or Gen5. Crucial factors include the system generation, display, app connectivity, BDU identification, sensors, rim magnet, and special features such as ABS or e-Shift. This guide explains the most important differences and leads to suitable product categories, solutions, and the Bosch Tuning Finder.
Bosch Gen1–Gen5BES2 & BES3 explainedBDU450, BDU3741, BDU3840Smart System & rim magnetNote ABS & e-Shift
Purion, Intuvia, Kiox, or Nyon usually indicate Bosch BES2. eBike Flow App, LED RemotePurion 200, Kiox 300, Kiox 500 or System Controller speak for Bosch BES3 / Smart System. With Bosch Gen4, it is always necessary to check more carefully, as both classic BES2 motors and early Smart system variants appear under this designation.
Note: If it is unclear whether a Bosch Gen4 bike belongs to the classic BES2 world or to the Smart System The Bosch Tuning Finder is the safest entry point.
Three characteristics are usually particularly helpful for a reliable classification: charging port, Display or control unit and Magnetic system on the rear wheelThis allows most Bosch e-bike systems to be quickly switched between previous generations, Bosch BES2 and Bosch BES3 / Smart System distinguish.
Quick rule: Purion, Intuvia, Kiox or Nyon are often indicative of Bosch BES2. eBike Flow App, LED Remote, Purion 200, Kiox 300 or Kiox 500 usually indicate Bosch Smart System / BES3 hin.
BES1 / EARLY SYSTEMS
Bosch Gen1
Early Bosch Classic Line with older system architecture and rectangular charging port.
Depending on the Bosch system, desired ease of use, and existing technical specifications, different solutions are possible. Some drivers prefer digital activation without traditional installation, while others rely on app functions, plug-and-play systems, or special solutions for... Smart System with rim magnet.
Note: If the Bosch system has not yet been definitively determined, it is recommended to first check the following:
Bosch Tuning Finder.
DIGITAL SOLUTION
No traditional installation desired
Particularly in demand among drivers who prefer a software-based solution and do not want a conventional chip installation.
The Bosch Tuning Finder helps in classifying BES2, Bosch Smart System / BES3, rim magnet, ABS, e-Shift and other special cases. This makes it easier to identify which product category or solution might be technically suitable.
Those already familiar with their Bosch system can directly compare different solutions. The choice depends, among other things, on the system generation, desired ease of use, installation effort, and the existing technical setup.
Important: At Bosch Gen4, Smart SystemFor rim magnets, ABS or e-Shift, a system check via the [unclear text] is recommended beforehand.
Bosch Tuning Finder.
With Bosch e-bikes, the exact system architecture is more important than the motor name alone. Terms like Bosch CX, Gen4, Gen5, Performance Line or Smart System These terms are often used interchangeably in everyday language. However, for technical classification and product selection, it is crucial to know whether the e-bike belongs to the early Bosch system, Bosch BES2, or Bosch BES3. Smart System for a trip to the Winterlude.
This distinction is particularly relevant for Bosch Gen4. A classic Bosch Performance Line CX Gen4 with BDU450 belongs to the BES2 world. An early Bosch Smart System CX with BDU3740 or BDU3741, on the other hand, already belongs to Bosch BES3. Both may appear in common parlance as "Bosch Gen4", but are not technically identical.
Define the system world: BES1, BES2 or BES3 / Smart System Classify via charging port, display, app and control unit.
Check display and app: Purion, Intuvia, Kiox or Nyon often support BES2; eBike Flow app, LED Remote, Purion 200, Kiox 300 or Kiox 500 for BES3.
Take BDU identifier into account: The exact drive unit identifier is particularly helpful for Bosch Gen4, Gen5, SX, PX, BDU37xx and BDU38xx.
Check magnetic system: For Smart System A classic spoke magnet or a rim magnet can be installed at the valve or on the rim.
Note special cases: ABS, ABS Pro, e-Shift, Speed Pedelec, Cargo Line, SX, PX or CX-R may influence the product selection.
Only then select the product world: Depending on the system, digital solutions, sensor solutions, boxes, modules or app-based products may be suitable.
Practical rule:
Classic Bosch systems from the BES1 and BES2 worlds often initially lead to
EBT Unlock Key.
Bosch Smart System / BES3 initially leads to
EBTsmart Unlock Key. At Smart System With a rim magnet, the
EBTsmart Unlock Key Switch
be relevant.
The following overview leads to the most important Bosch categories and product areas. It is particularly useful if you are already generally familiar with the system. If you are unsure, you should use the Bosch Tuning Finder beforehand.
The following table serves as a technical guide. For product selection, not only the engine designation is important, but above all the system architecture: BES1, BES2, or... Bosch Smart System / BES3. Especially with Bosch Gen4 and Gen5, the display, app, charging socket, BDU identification, rim magnet, ABS and e-Shift should also be checked.
Note: BDU designations with "Y" are placeholders for sub-variants of a motor family. For a specific product recommendation, the complete BDU identification, display, app connectivity, and magnet system should be checked if possible.
The biggest source of error at Bosch is the confusion between classic Gen4 and BES2. Bosch Smart The system is based on BES3. Both systems can be described in everyday language as "Bosch Gen4" or "Bosch CX," but they are technically different. Therefore, the charging port, display, app connectivity, BDU (Battery Distribution Unit), and magnetic system are crucial for selecting the right product.
Bosch BES2: classic Gen2–Gen4 world
classic oval Bosch charging socket
Typical displays: Purion, Intuvia, Kiox or Nyon
No eBike Flow app as a central system app
classic Bosch Gen4 CX, often referred to as BDU450 / BDU450 CX
typical product range: EBT Unlock Key and classic Bosch solutions
Mnemonic: Bosch Gen4 is not a definitive system designation. A Bosch Gen4 CX with a BDU450 motor belongs to the classic BES2 system. An earlier Smart System CX with a BDU3740 or BDU3741 motor, on the other hand, belongs to Bosch BES3. If you are unsure, the Bosch Tuning Finder is the most reliable starting point.
The BDU identifier designates the Bosch Drive Unit and is particularly helpful for Gen4, Gen5, SX, PX and Smart System bikes in terms of precise technical classification. It is often more crucial than terms like "CX", "Performance Line“ or “Gen4”.
BDU example
Typical classification
Important notes
BDU450 / BDU450 CX
classic Bosch Gen4 CX / BES2
not automatically Smart System
BDU3740 / BDU3741
early Bosch Smart System / BES3
In everyday life, it can still be described as Gen4.
BDU37xx
Smart system family with sub-variants
"xx" is a placeholder, check the exact last digits
BDU3840 / BDU3863 / BDU3883
Bosch Gen5 / BDU38xx family
Smart System, check the exact variant and special cases
BDU31xx / BDU33xx / BDU34xx
other smart system families
Also pay attention to the display, app, magnet type, ABS and e-Shift.
Important: Abbreviated designations such as BDU37, BDU37xx, or BDU38xx are often insufficient for a reliable product recommendation. If possible, the complete BDU identifier should be displayed in the eBike Flow app or on the device itself. Drive Unit being checked.
At the Bosch Smart System / BES3 is not only about the motor. The position of the speed sensor and the magnet type also play an important role. A classic spoke magnet requires a different product approach than a rim magnet or valve magnet. The appropriate category for rim magnet systems is available and includes dedicated smart system solutions.
Classic spoke magnet
The magnet is visibly attached to a spoke. The sensor is usually located on the rear stay or near the brake disc. Smart system bikes without a rim magnet generally use different solutions than valve or rim magnet systems.
If no classic spoke magnet is visible, the magnet is often located at the valve, in the rim, or as a special rim magnet. In this case, you should always check the specific rim magnet category.
If no spoke magnet is visible, a standard smart system solution should not be chosen prematurely. First, it should be checked whether a rim magnet or valve magnet system is present.
Within the Bosch portfolio, there are several digital product worlds. These should be clearly differentiated according to system generation and sensor logic: classic Bosch systems, Bosch Smart System / BES3 and Smart System special cases with rim magnet.
BES1 / BES2
EBT Unlock Key
For classic Bosch systems from Gen1 to Gen4 or BES1/BES2. Relevant for older Bosch systems without Smart System architecture.
For Bosch Smart System / BES3 with and without rim magnet. The product page lists the EBTsmart Unlock Key as a digital solution for compatible smart system bikes.
At the Bosch Smart Depending on the cockpit, the USB port on the system isn't always located where you'd expect it to be. Especially with the Kiox 300 or Kiox 500, the relevant port is often not directly on the display, but rather on... LED Remote or system controller. Detailed instructions for USB access are available and can be linked as a further practical article.
-Setup
Probable USB location
Important notes
Kiox 300 / Kiox 500 + LED Remote
LED Remote
often accessible from below, often behind a protective cap
Mini Remote + System Controller
System Controller in the top tube
Depending on the bike, the cover must be carefully removed.
Purion 200 / Purion 400
on the device itself
Pay attention to the protective cap or concealed cover.
The following technical articles delve deeper into key Bosch topics such as Gen5, wheel magnet, USB access, licensing solutions, model assignment and system terms.
Bosch tuning solutions differ not only in product name, but above all in their technical method. Key factors include system generation, sensor technology, installation effort, app connectivity, and special features such as wheel magnets, ABS, or e-Shift.
Check installation, connector, motor family and app compatibility
Chip without app
VOLspeed, PearTune, MBIQ, MTT SmartChip
Permanent hardware solution without app control
Connector, motor family, Smart SystemNote ABS, e-Shift and wheel magnet
Note: At Bosch Smart Before selecting any product, the system/BES3 should be checked to determine whether it uses a classic spoke magnet or a rim magnet. ABS and e-Shift can also influence the selection.
The appropriate solution arises from the system architecture. Therefore, it should first be clarified whether it is a Bosch BES1/BES2 system, Bosch Smart System / BES3 or a special case of a smart system with a rim magnet.
Bosch Gen1–Gen4 / classic systems
Older Bosch systems are usually BES1 or BES2. Typical systems are Gen1, Gen2, Gen3 and the classic Gen4 CX with BDU450.
If the charging port, display, BDU, or magnetic system is unclear, guesswork is not recommended. The finder guides you step-by-step to the appropriate product category.
The selection should not be based solely on terms like Bosch CX, Gen4, or Gen5. The Bosch Tuning Finder helps in classifying BES2, BES3, Smart System, BDU, rim magnet, ABS and e-Shift and leads to the appropriate product world.
BES2 is often recognizable by its Purion, Intuvia, Kiox or Nyon displays, as well as the classic charging port. BES3 / Smart System can usually be recognized by the eBike Flow app, LED Remote, Purion 200, Kiox 300 or Kiox 500.
Is Bosch Gen4 always BES2?
No. Bosch Gen4 can be classic BES2, but there are also early Smart System variants. Therefore, the charging port, display, app connectivity, and BDU should always be checked.
Why is the wheel magnet important?
For Bosch Smart The magnet can be located on the rim or the valve. In this case, different product logic applies than with a classic spoke magnet.
What does BDU mean?
BDU stands for Bosch Drive UnitThe exact BDU identifier helps in assigning the engine family, generation and suitable solution.
Which solution is suitable for Bosch Smart System with rim magnet?
For Smart System When using a wheel magnet, always check the specific wheel magnet category. Depending on the configuration, EBTsmart Unlock Key or EBTsmart Unlock Key Switch may be relevant.
What should be considered regarding ABS or e-Shift?
ABS and e-Shift are special cases and can influence product selection. The exact system logic should always be checked in such configurations.
What do I do if I cannot reliably identify my Bosch system?
Then the Bosch Tuning Finder should be used. It guides you step by step through system generation, display, app, BDU, magnet type and special cases to the appropriate product range.
Do you need help choosing the right tuning product or have questions about ordering, shipping, or invoicing? Here you'll find the quickest way to a suitable answer.
Find out the exact model name of your engine. (Read the instructions and/or data sheet for the e-bike or e-scooter). Now turn the Filter im
Shop on your engine. Or: Read the Guide Completely. In my experience, you'll know 80% more afterwards than before.
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