The Brompton C Line (12-Speed) is the ultimate long-range, terrain-tackling iteration of the iconic hand-brazed steel folding bike. Built around Brompton's precision-drawn, heat-treated steel frame, this model introduces an expansive 12-speed drivetrain delivering a 402% gear range—combining a 3-speed internal gear hub with an external 4-speed derailleur. Tipping the scales from 12.0 kg (26.5 lbs), it retains the legendary, compact 20-second fold (25.3" H x 23" W x 10.6" D) that allows it to transition effortlessly between city streets, train commutes, office storage, and steep hill climbs.
Designed for everyday practical mobility, the C Line 12-Speed comes factory-equipped with full-coverage mudguards, high-efficiency 65mm Advance Roller Wheels for smooth towing when folded, and Brompton's front carrier block for clip-on luggage. Available in three distinct handlebar geometry setups (Low, Mid, High) and supported by durable 349mm (16-inch) wheels with Schwalbe Marathon Racer tires, this build delivers the versatility of a full-size touring machine within an ultra-compact, portable footprint.
Specifications Breakdown
Frameset & Ergonomics
Main Frame: Precision-Drawn Heat-Treated Steel Tubing with Hand-Brazed and Auto-Brazed Joints.
Rear Frame & Fork: Brompton Advance Rear Frame (Steel) & Brazed Steel Fork.
Handlebar Options: Low (Sporty/Flat), Mid (Neutral/Relaxed), or High (Upright) Riser Bars.
Folded Size: 25.3" H x 23" W x 10.6" D (58.5cm H x 56.5cm W x 27cm D).
Seatpost & Saddle: Standard / Extended / Telescopic Black Seatpost; Brompton Standard Saddle with Integrated Carry Handle.
Grips & Hinge Clamps: Lock-On Soft-Compound Rubber Grips, Composite Hinge Clamp Levers.
Drivetrain & Brakes
Drivetrain System: Brompton 12-Speed Drivetrain (402% Gear Range).
Rear Hub & Derailleur: Brompton Wide Ratio 3-Speed Internal Gear Hub + Direct-Mount 4-Speed External Derailleur.
Shifters: Dual Trigger Setup (4-Speed External Derailleur Shifter + 3-Speed Hub Gear Shifter).
Crankset: 6061 Forged Aluminium Crank arms with 50T Chainring and Integrated Chainguard.
Sprockets: Brompton 4-Speed Sprocket Set (11-18T).
Brakes: Brompton Dual-Pivot Alloy Caliper Brakes (Front & Rear).
Wheels & Accessories
Rims & Hubs: Double-Wall Alloy Rims (28H), Sealed-Bearing Front Hub, 3-Speed Internal Rear Hub.
Tires: Schwalbe Marathon Racer, 349 x 35C (16 x 1-3/8"), Puncture-Resistant with Reflective Sidewalls.
Pedals: Brompton Folding Left-Hand Pedal, Non-Folding Right-Hand Pedal.
Integrated Accessories: Full-Coverage Mudguards, Front Carrier Block Adaptor (Luggage System), 65mm Advance Roller Wheels.
Approx. Weight: From 12.0 kg / 26.5 lbs (Max System Weight: 110 kg).
Key Highlights
Expansive 402% 12-Speed Range: By pairing a low-maintenance 3-speed internal gear hub with a lightweight 4-speed external derailleur, the bike provides ultra-low gearing for steep hills alongside high gearing for fast flat sprints.
Iconic Under-20-Second Compact Fold: Folds cleanly down into a locked package that fits under desks, in car trunks, or on public transit.
Hand-Brazed Steel Frame Construction: Handmade in London using heat-treated steel tubing, offering high frame stiffness, power transfer, and decades-long structural durability.
Integrated Luggage Carrier Block: Frame-mounted front carrier block transfers bag weight directly to the chassis rather than the handlebars, keeping steering stable even when carrying heavy cargo.
Customizable Fit & Handlebars: Offered in Low, Mid, and High handlebar riser profiles alongside standard, extended, and telescopic seatposts to accommodate riders of varying heights.