Produce any interesting machine and someone will want to customise it. Engineer Steve Parry has been producing custom folding bikes to order for over a decade – concentrating on the Brompton in recent years.

In practice, you can order a Brompton from Mr Parry with just about any choice of parts and accessories, from the single-speed on this page to the all- singing, all-dancing 14-speed overleaf.

The basic single speed weighs 9.7kg (21.3lb) – around two kilograms lighter than a standard L3. This weight saving is achieved largely with high-tech materials: titanium/carbon fibre telescopic seat pillar, carbon fibre forks, stem and cranks, with MKS demountable pedals.

The single-speed rear hub is a Shimano freehub with all but the 11-tooth sprocket removed to save weight. Unusually, the bike is fitted with slightly oversize Birdy 18-inch wheels and Schwalbe Stelvio tyres. Price is £1,200 – broadly the same as the equivalent Bike Friday, Airnimal or Bridgestone Moulton.

In contrast, the Rohloff version features every conceivable accessory and weighs 13.9kg (30.5lb).The seat pillar is the same, but the lightweight saddle has been replaced with a Brookes leather item, and the cranks are Shimano 105.The handlebar stem is carbon fibre again, but this time with integral suspension. Brakes are superb – Hope hydraulic discs front and rear, giving a best stop of around 0.75G before lifting the rear wheel.The Brompton rear rollers are replaced with SP narrow discs and the rear suspension is fitted with a hook to prevent involuntary folding. Finally, there’s that hub… Steve fabricates his own rear frames to accommodate the much wider 14-speed Rohloff, but the folded size of the bike is little changed, and the system works well. Price? About £2,000 depending on the exact spec.That’s about the same as the Birdy Grey or Airnimal Ultima.

SP Bicycles
tel 01934 516158
mail spbicycles@btopenworld.com