SUNCORD Magnetic Chain Supporter ⁣ for Brompton Bicycle G Line

For use with integrated external bottom brackets (BB) 

Ring thickness: 2 mm

Adjustable travel: 26 mm 

Available with 3 different lengths of carbon plates to choose from 
Compatible with 44T to 58T round chainrings (not suitable for oval chainrings).

Applicable models: Brompton, Birdy, and other vertically-folding bikes.

Installation Notes:

• The magnetic pulley must be within 4 mm — the key principle is that it should not touch the chain.

• If the gap is too large, chain drop may occur.

Working Principle:

When the bike is folded, the chain is automatically attracted and held in place, keeping it engaged with the chainring teeth and preventing slipping. This naturally creates an anti-drop effect for the chainring.
When the frame is unfolded, the chain automatically detaches from the magnetic pulley.
For best results, use it together with the magnetic derailleur chain supporter.