The Brompton factor
Bromptons account for the majority of used folding bikes sold in the UK. They are made in London, they fold smaller than most competitors, and the after-market support is better than any other folding bike brand. A twenty year old Brompton can still be serviced by any Brompton dealer, and replacement parts for almost every component on the bike are available off the shelf.
The flip side is price. A used Brompton holds its value extraordinarily well. A five year old Brompton in good condition often sells for seventy percent of the current new price. You are not paying for a cheap bike. You are paying for an engineered product that works, lasts and can be resold later with almost no loss.
Bromptons come in several gearing options. The two-speed is the lightest and simplest. The three-speed Sturmey Archer hub is the classic setup and is almost maintenance free. The six-speed combines the three-speed hub with a two-speed derailleur and gives you the widest range, at a small weight penalty. The newer twelve-speed is a more modern setup but the parts cost more when it comes time to service.
The alternatives to a Brompton
Dahon, Tern and B'Twin make folding bikes that generally fold a bit larger than a Brompton but offer more standard bike feel. If you are a taller rider or you want something that rides more like a normal bike over longer distances, a Dahon or Tern is worth considering. Parts are more standard than on a Brompton, but the fold is not as compact.
Birdy is a more premium Dutch-made folder with suspension front and rear. It folds slightly larger than a Brompton but rides far more smoothly. Prices on the used market are high and parts are specialist, so ownership can get expensive if something breaks.
