A key feature of the Brompton is the compactness and practicality of its fold. With a little practice, this is achieved without any difficulty in 10 - 20 seconds. The dimensions of the folded bike are: 585mm high x 545mm long x 270mm wide (23" x 21.5" x 10.6").
When folded, a Brompton stays locked together, making an extremely compact package little larger than its wheels. The folded package may be picked up without any risk that the bike will unfold - reassuring when running for a train or handing it to a cloakroom attendant!
There are no projections or loose parts with the folded package and, using the frame or saddle as a handle, it carries like a small suitcase, lightweight and easy to manage. The fold is designed to keep vulnerable parts, like lights and cable-runs, out of harm's way and, by folding them in, to keep the greasy chain and gears away from clothing and luggage. Small rollers allow the bike to be pushed into inaccessible corners.
Full instructions for folding and unfolding, with diagrams, are given in the Owner Manual but these are the basic steps:
All Bromptons have rear suspension, which also allows instant "parking" of the bike:
1. Park the bike by swinging the rear wheel under the main frame - the Brompton will stand on its own, leaving both hands free;
2. Unclamp and fold back the front wheel - the right hand pedal should be moved out of the way if necessary - and hook onto the rear frame
3. Unclamp and lower the handlebars and saddle, and stow the folding pedal; these items can be dealt with in any order after the second step
1. Raise and clamp the saddle and handlebar, and unfold the folding pedal; these items can be dealt with in any order, but they must be unfolded before moving on to step 2
2. Unfold and clamp front wheel; the bike is now parked
3. Lift up the rear end of the bike - a little flick is usually the most effective method - to swing the rear wheel out; the bike is ready to ride
The key to understanding the fold of the Brompton is the seat pillar: it is the seat pillar which locks the folded package together by projecting down from the main frame, so preventing the rear frame from rotating, which in turn prevents the front wheel from swinging free. If the seat pillar is visible below the main frame, do not try to park or unpark the Brompton, and do not try to hook or unhook the front wheel from the rear frame. Similarly, if the seat pillar is not fully down, the folded package may fall open when the bike is picked up.