UNLOCK THE FULL POTENTIAL OF YOUR BOSCH E-BIKE
Welcome to our in-depth guide on Bosch e-bike tuning. If you're looking to maximise performance and enjoy a more dynamic riding experience, you're in the right place. This guide covers everything you need to know: the different Bosch motor generations, tuning methods, compatible products, and the legal aspects every rider should understand.
WHY CONSIDER BOSCH TUNING?
Bosch drives are among the most widely used e-bike systems in the world. Whether your bike features an Active Line, Performance Line, or Performance Line CX motor, it’s typically limited to a top speed of 25 km/h. Tuning removes this restriction, allowing the motor to deliver its full potential. This is especially valuable for riders who want more power for steep climbs, faster speeds for commuting, or a sportier overall feel. When used responsibly and within legal boundaries—such as on private property or in countries that permit tuning—this can significantly enhance your e-bike experience.
BOSCH TUNING BY MOTOR GENERATION – IN DETAIL
Bosch Gen1 – Classic+ (BES1)
The original Bosch drive system: robust, somewhat loud, but still running strong on many early e-mountain bikes. It’s a relatively easy motor to derestrict and remains a solid choice for basic tuning. (Read more about Bosch Gen1 in the blog.)
Bosch Gen2 – Active / Performance Line (BES2)
The second-generation motors introduced improved power and quickly became widespread across mid-range e-bikes. Known for being particularly tuning-friendly, Gen2 systems remain popular with users looking for performance upgrades. (Read more about Bosch Gen2 in the blog.)
Bosch Gen3 – Active Line Plus (BES2)
Whisper-quiet and efficient, Gen3 motors are commonly found on newer e-mountain bikes. Though still part of the BES2 system, they pair well with modern displays and are easy to tune using wired and box tuning methods. (Read more about Bosch Gen3 in the blog.)
Bosch Gen4 – Performance Line CX (BES2)
A favorite among e-MTB enthusiasts, the Gen4 CX motor delivers up to 85 Nm of torque and has powered many premium bikes since 2020. It's highly responsive to tuning and remains one of the most sought-after motors for performance enhancement. (Read more about Bosch Gen4 in the blog.)
Bosch Gen4 – Smart System (BES3)
Launched in 2022, the Bosch Smart System (BES3) introduced a completely new architecture, including new displays, connectors, and deep integration with the eBike Flow app. Despite added anti-tuning measures, several tuning options remain available. (Read more about Bosch Smart System Gen4 in the blog.)
Bosch Gen5 – Smart System 2024+ (BES3)
This latest evolution of the Smart System adds even more connectivity and control—but also tighter restrictions. Bosch is increasingly active in blocking unauthorised modifications. However, tuning remains possible using select compatible devices. (Read more about Bosch Gen5 in the blog.)
Bosch Rim Magnet Systems (BES3)
Instead of the traditional spoke magnet, newer BES3-equipped e-bikes feature a rim magnet mounted directly on the valve stem. This design makes many older tuning boxes incompatible. Only a few specialised sensor-based tuning solutions are currently effective. (Read more about Bosch rim magnet systems in the blog.)
BOSCH GEN4 VS. GEN4/GEN5 SMART SYSTEM: KEY DIFFERENCES EXPLAINED
Although Bosch Gen4 motors may look nearly identical from the outside, they exist in two very different system versions: the long-established BES2 system and the newer, more connected BES3 Smart System. This difference plays a crucial role in tuning compatibility.
BOSCH GEN2 – GEN4 (BES2)
• Uses the BES2 system (in use since 2014)
• Equipped with a round 4-pin charging socket
• Compatible with classic Bosch displays such as Purion, Intuvia, Kiox1, Nyon1
• Still widely used across many e-bike models
• Numerous tuning solutions are available for this system
⚠️Not compatible with Smart System components
[Explore BES2 tuning options }
BOSCH GEN4 – GEN5 (BES3 SMART SYSTEM)
• Introduced in 2022 with the Bosch Smart System
• Features a new 2-pin magnetic charging socket (oval shape)
• Only works with Kiox 300, Kiox 500, or the LED Remote
• Requires setup and management through the Bosch Flow App
• Much more restrictive regarding tuning but still tuneable
⚠️ Important: Some models use a rim-mounted magnet, which affects tuning compatibility
[See compatible BES3 tuning}
BES2 OR BES3: UNDERSTANDING THE PRACTICAL DIFFERENCES
The key visual difference between Bosch BES2 and BES3 systems lies in the charging and diagnostic socket. BES2 uses the classic round 4-pin connector, while BES3 (Smart System) features a new oval, magnetic interface.
But the real distinction goes deeper—into the software architecture. BES2 systems remain highly tunable, with a wide range of compatible tunings and methods available. In contrast, BES3 is encrypted at the system level, making tuning far more restricted and requiring smart, precisely engineered solutions to achieve similar results.
For riders who prioritise flexibility and broader compatibility, BES2 is still the more open platform. For those using newer Smart System bikes, tuning is possible—but demands specialised knowledge and carefully developed devices.
