Chainrings for eBike conversion kits must withstand the combined torque of motor and rider — requiring robust construction and compatibility with mid-drive motor interface standards.
What chainring size is best for an eBike conversion kit?
For mid-drive kits like Bafang, a 42T–46T narrow-wide chainring is the standard recommendation — providing appropriate gearing ratios when combined with a 7–10 speed rear cassette. Smaller rings (38T–40T) work better in very hilly terrain like Vancouver's North Shore.
What is a narrow-wide chainring and why does it matter on eBikes?
Narrow-wide chainrings have alternating wide and narrow teeth that engage both inner and outer chain link plates, retaining the chain more securely. This is critical on eBikes where motor torque and vibration can throw the chain on standard chainrings without a front derailleur or chain guide.
Are Bafang mid-drive chainrings standard sizes?
Bafang mid-drive motors (BBS01, BBS02, BBSHD) use a proprietary chainring interface with a specific bolt circle diameter. Bafang-compatible aftermarket chainrings (42T, 44T, 46T, 48T) are widely available. Always specify your Bafang model when purchasing chainring upgrades.
Do hub motor eBikes need special chainrings?
Hub motor e-bikes use a standard bicycle chainring on the crank — no proprietary interface required. Any standard BCD-compatible chainring in the appropriate size works. For single-speed hub motor setups, a narrow-wide chainring prevents chain drop without a front derailleur.
How long does a chainring last on an eBike?
With regular chain replacement (every 1,500–2,000 km), a quality steel chainring lasts 10,000+ km on a mid-drive eBike. Aluminium chainrings wear faster under motor torque and are generally not recommended for high-power eBike applications.