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Description
OEM Replacement Chainring for Bosch Gen 2 Mid-Drive E-Bikes
The Bosch Chain Wheel Disc (Chainring) - 20t, BDU2XX is an original equipment manufacturer (OEM) replacement chainring designed specifically for Bosch Gen 2 mid-drive electric bike systems. Compatible with Bosch Active Line, Performance Line, and Performance Line CX drive units from model year 2014 onwards, this steel chainring provides reliable power transmission and precise shifting performance for e-bikes. The 20-tooth configuration offers a balanced gear ratio that works well for mixed terrain riding—providing enough torque for climbs while allowing for comfortable pedaling at speeds beyond the motor's assistance cutoff (typically 20-28 mph depending on your system). The reinforced steel construction is engineered to withstand the higher torque loads generated by e-bike motors, making it more durable than standard bicycle chainrings.
This chainring features a direct mount design that fits the Bosch Gen 2 splined interface, and the specially designed tooth profile ensures excellent chain retention even under the increased power of electric assist. Whether you're replacing a worn chainring or customizing your gearing setup to better match your riding style and terrain, this genuine Bosch part delivers the quality and compatibility you need. Installation requires a crank puller and Bosch spider/lockring tool to remove the crankarms and access the chainring mount. The 20-tooth option is a popular upgrade from the stock 15t or 18t chainrings on many Bosch e-bikes, as it provides a taller gear for faster cruising speeds while maintaining adequate climbing ability when paired with an appropriate rear cassette.
Built to Last
- Genuine Bosch OEM replacement part—ensures perfect fit and compatibility.
- 20 teeth configuration—balanced gear ratio for mixed terrain and comfortable high-speed pedaling.
- Steel construction—reinforced chainring engineered to handle e-bike motor torque loads.
- Direct Mount Bosch Gen 2 interface—splined design for secure, precise mounting.
- Compatible with Bosch Active Line, Performance Line, and Performance Line CX drive units.
- Fits BDU2XX generation Bosch motors (Gen 2 mid-drive systems from 2014 onwards).
- Specially designed tooth profile—ensures excellent chain retention under electric assist power.
- Black finish—matches OEM appearance and resists corrosion.
- More durable than standard chainrings—built to withstand increased torque from e-bike motors.
- Size: 42 x 3/32" (standard e-bike chain width).
- Popular upgrade option—provides taller gearing for better performance beyond motor cutoff speed.
- Allows customization of gear ratios—fine-tune your setup to match riding style and terrain.
- Optimal power transfer—engineered to maximize efficiency from rider and motor to drivetrain.
- Reliable shifting performance—precise design ensures smooth gear changes.
- Installation requires crank puller and Bosch spider/lockring tool (not included).
- May require Bosch lockring and sealing ring for complete installation (not included).
- Note: Larger chainrings may have limited clearance with motor casing—check fitment on your specific bike.
- Bosch part number: 1270016205.
UPC / Part Numbers
| Option | SKU | UPC |
|---|---|---|
| Default | 1270.016.205 | 4047025220590 |
