Brother Cycles Stroma Frameset - 2025

The Stroma is a versatile, year-round road bike suited to the ever changing weather and road surfaces of the UK. It’s an all-road, fast gravel, endurance bike. However you want to classify it, the Stroma is an extremely capable machine – designed to be fast, responsive and supremely comfortable over distance, no matter how rough it gets.

The Stroma truly lives up to its namesake; a remote island off the rough north east coast of Scotland, battered by ferocious weather and near impenetrable tides.

The frame is constructed out of Reynolds 725 steel; a heat treated tubing famed for its strength and weight saving properties and an ideal material for the challenges posed by year round road cycling. We’ve matched this with the Brother full carbon road fork up front giving you a lightweight and responsive front end with optimum power transfer – this has also been updated for 2025 to now include internal dynamo routing – further enhancing the Stroma’s endurance credentials. The frame and fork have fitted eyelets for full mudguards and clearance for up to 38mm tyres or 32mm with mudguards.

Other features include thru-axle flat-mount dropouts, replaceable dropout inserts, 2 x bottle cage and rear rack mounts, and Di2 routing – which neatly doubles up as internal routing for a rear dynamo light.

Features
Frame tubing: Reynolds 725 heat treated chromoly double-butted main triangle, ED coated. Reynolds 520/500 custom formed rear triangle.
Brake compatibility: flat mount, 160mm max rotor size
Rear Dropouts: 12x142mm TA (included)
Seat post diameter: 27.2mm
Seat clamp diameter: 30mm (included)
Headset: 44mm, ZS44/28.6 upper, EC44/40 lower (not included)
Front derailleur clamp diameter: 28.6mm
Bottom bracket shell: 68mm bottom bracket, ISO threaded
Maximum tyre clearance: up to 700c x 35mm (30mm with mudguards)
Fork: 1.5″ – 1.1/8″ tapered steerer carbon monocoque disc fork, mudguard mounts. 12x100mm TA (included), dynamo routing
2 sets bottle cage mounts on all sizes
Rear rack and mudguard mounts
Di2 cable ports
Chainring clearance: up to 53-39t double, 50t single
Frame weight (medium): 1.97kg
Fork weight (uncut steerer): 0.50kg