Brompton Project Bike S3E-X Superlight Polished Titanium 7.23 KG Bicycle

This is a titanium folding bike built from a frameset sourced from Asia and assembled over several months with carefully selected lightweight components. The frame, forks, seatpost, stem and rear triangle are all titanium, as are the low-rise handlebars, keeping the overall weight down to 7.23kg. That's genuinely light for a rideable folding bike, and the titanium construction means it'll resist corrosion and maintain its stiffness even as the weight drops.

The drivetrain uses a 50-tooth chainring paired with a 13, 14 and 15-tooth sprocket cluster, giving a narrow but practical gear range suited to flat urban terrain and the occasional gentle gradient. The chainset is Ace specification, with an Ace titanium bottom bracket keeping friction minimal. Power transfers through an MKS pedal set with titanium axles—the left pedal is removable, which is useful when folding the bike for storage. A lightweight derailleur handles gear changes, whilst a KMC silver chain and Alligator I-link cables complete the transmission.

Stopping power comes from Ciamillo brake stirrups fitted with Nest alloy brake levers, delivering caliper-style braking from both wheels. The 16-inch wheels are relatively lightweight and come shod with Schwalbe Kojak slick tyres, which roll efficiently on smooth surfaces. The front wheel uses a quick-release mechanism for easier folding. A Tange alloy headset keeps the steering smooth, and Ace roller wheels—essentially the folding mechanism—work alongside titanium hinge clamp levers and a titanium lower stop disc to manage the fold itself.

The saddle is a Bontrager silver model, chosen for its lightweight profile, whilst the seatpost clamp lever is silver alloy. Other details reflect the weight-conscious build throughout: titanium wheel nuts, titanium rear axle spindles and a titanium pedal holder mounted on the rear axle. All fasteners are either titanium or alloy rather than steel. Lighting is handled by a pair of Kiley LED USB-rechargeable units fitted front and rear, keeping the bike road-legal without adding significant weight. An Aceoffix silver luggage block allows for basic carrying capacity if needed. The bike folds in the traditional manner, making it compact enough for train storage or office cupboards once packed away.