Brompton parts guide
Which battery bag and frame does my Brompton Electric need?
Every Brompton Electric bag has a frame inside it, and the frame is what must match your battery and your bike. Answer two questions and you have your part.
First, find two things
Electric C Line or P Line — 16" wheels, the classic folding Brompton shape. Electric G Line — 20" wheels, the bigger model introduced 2024.
Check the label. The original battery carries the BMZ Drive Systems logo. The newer battery carries the green Greenway logo. Every Electric G Line battery is a Greenway.
The whole decoder in one table
The bag itself doesn't care which bike or battery you have — any Brompton Electric bag works everywhere. What must match is the frame inside the bag: it's what docks the battery to the bike.
| Your bike | Your battery | Frame you need | Note |
|---|---|---|---|
| Electric C Line / P Line | BMZ (original) | Your original BMZ-only frame — or the Adapter frame | Both hold a BMZ battery. Buying today, get the Adapter frame: it also takes a Greenway, so a future battery swap needs no new frame. |
| Greenway | Adapter frame | The original BMZ-only frame will not hold a Greenway battery. | |
| Electric G Line | Greenway | Greenway (V2) frame | The G Line uses its own frame — C/P Line frames don't fit it. |
| BMZ (original) | None — do not do this | A BMZ battery must never be used on a G Line: it will damage the bike, not just fit badly. |
Swapping a bag between bikes
Own two Bromptons? The bag travels fine — swap the frame inside it.
- G Line bag onto a C Line or P Line: not as it is. Put an Adapter frame in the bag and it works (the G Line's Greenway battery docks in the adapter).
- C Line / P Line bag onto a G Line, with a Greenway battery: not as it is. Put a Greenway (V2) frame in the bag first.
- C Line / P Line bag onto a G Line, with a BMZ battery: never. It's not just a bad fit — a BMZ battery will damage a G Line. The G Line needs a Greenway battery.
Frames come in two sizes. Small frames fit the small bags (City, Essential); large frames fit the large bags. Match the frame size to your bag as well as to your battery.
The parts
Not sure which battery or bag you have? Email a photo of the battery label to info@clevercycles.com, or bring it by the shop — we'll sort it while you wait.
