BOSCH GEN2 & GEN3 MOTORS – TUNING, COMPATIBILITY, AND KEY DIFFERENCES
Bosch’s e-bike legacy
Bosch, founded in Stuttgart in 1886, is one of the most respected names in engineering and technology—best known for its work in automotive systems, appliances, and power tools. In 2009, Bosch entered the e-bike market with the creation of Bosch eBike Systems. The first Bosch-powered e-bike was presented at the Eurobike trade fair that same year, with series production launching in 2011. Since then, Bosch motors have become the standard in over 50 premium European e-bike brands.
OVERVIEW: BOSCH GEN2 AND GEN3 MOTOR SYSTEMS
Following the original Classic Line (Gen1), Bosch introduced two second-generation drive systems in 2014: the Active Line and the Performance Line, both part of Gen2 (BES2). The Active Line was developed for comfort-oriented riders and everyday cyclists, offering smooth support and an optional coaster brake configuration. The Performance Line, on the other hand, was aimed at more sporty and performance-focused riders, delivering higher torque and stronger responsiveness.
Both systems feature Bosch’s three-sensor technology, which continuously measures pedal force, cadence, and speed three times per second to ensure optimal pedal assistance. As with all Bosch systems, these are mid-drive motors.
In 2016, Bosch released the Performance Line CX, a top-tier model designed specifically for e-mountain biking. Two years later, in 2018, the third generation of motors (Gen3) launched with a revised version of the Active Line and a brand-new motor called the Active Line Plus. These newer drives are quieter, more compact, and smoother in power delivery thanks to a redesigned internal transmission.
FIRMWARE VERSION 1.8.4.0 AND ANTI-TUNING DETECTION
Starting with firmware version 1.8.4.0, Bosch implemented anti-tuning detection even in Gen2 and Gen3 systems. If your e-bike is running this version or higher, tuning devices originally made for Gen4 motors may be required to ensure compatibility.
SPECIFICATIONS OVERVIEW OF BOSCH GEN2 AND GEN3 MOTORS
The Bosch Active Line in Gen2 supports speeds up to 25 km/h and offers 48 Nm of torque. It is available with both derailleur and hub gear configurations, and in some cases, includes a backpedal brake option.
The Bosch Performance Line from model years 2015 to 2020 delivers 63 Nm of torque and offers assistance up to 275%, with support for cadences above 120 rpm. A Speed version is also available, extending assistance to 50 km/h.
The Performance Line CX, also part of Gen2, is tuned for higher power and steeper gradients. It supports up to 75 Nm of torque and 300% pedal assistance, also at cadences over 120 rpm.
For Gen3, the Active Line 2018 supports 25 km/h speeds, delivers 40 Nm of torque, and provides up to 250% assistance with a cadence range up to 100 rpm. The Active Line Plus is slightly stronger at 50 Nm torque and supports 270% pedal assistance, up to 105 rpm. The Performance Line from 2020, also part of Gen3, pushes torque to 65 Nm and supports 300% pedal assistance above 120 rpm cadence.
Some sources classify the Active Line under Gen2 and the Active Line Plus under Gen3, while others consider both as part of Gen3. This distinction has no practical effect, as the same tuning devices are compatible across all these systems, except where newer firmware versions require Gen4-compatible devices.
BOSCH GEN3 – ACTIVE LINE 2018 & ACTIVE LINE PLUS
The 2018 launch of the revised Active Line and new Active Line Plus marked a step forward in Bosch’s drive technology. These motors are significantly lighter, quieter, and more compact than earlier models. Thanks to a newly developed transmission, both units offer smoother and more natural pedal support. A key advantage of this setup is that the motor creates virtually no resistance when turned off, allowing riders to pedal normally without drag.
The Active Line 2018 was developed for everyday urban use and flat terrain. It weighs 2.9 kg and delivers 40 Nm of torque. In contrast, the Active Line Plus is designed for more versatile riding, including hilly routes and longer distances. It weighs 3.2 kg and outputs 50 Nm of torque. Both models are compatible with current Bosch displays and support both derailleur and hub gearing.
CAN BOSCH GEN2 AND GEN3 MOTORS BE TUNED?
Yes, both Gen2 and Gen3 motors—including the Active Line, Performance Line, CX Line, Active Line Plus, and Active Line 2018—can be tuned. Numerous tuning solutions are available. If your e-bike uses firmware version 1.8.4.0 or newer, make sure the tuning device is compatible with Gen4 systems.
WHICH TUNING ARE AVAILABLE?
You’ll find a wide selection of trusted and efficient tuning devices compatible with Bosch Gen2 and Gen3 motors. These devices help remove speed limits and give you more freedom and performance on your e-bike.
