Brother Cycles Stroma Electric Blue - Frameset

The Brother Cycles Stroma is a frameset for anyone who wants to build a fast road bike that doesn’t have to stay at home just because the weather or road surface gets worse. The Stroma is designed for year-round cycling and sits somewhere between road, all-road, and fast gravel. Our advice is much the same as before: ignore the weather gods and ride anyway.

The geometry is clearly geared toward road riding, but the Stroma is more practical than a traditional race frame. There is clearance for tires up to 700 × 38 mm, or 32 mm with full-length mudguards, giving you much more freedom when the pavement gets rough or the ride continues onto gravel. Mudguard and rack mounts also make the frame work very well as a fast year-round bike, commuter, or long-distance road bike.

The frame has a heat-treated Reynolds 725 main triangle and a custom-shaped Reynolds 520/500 rear triangle. Up front is a Brothers carbon fork with a 12 × 100 mm thru-axle, mudguard mounts, and internal routing for a dynamo cable. The combination of a steel frame and carbon fork gives the Stroma the blend of compliance and direct feel that suits a fast bike for long days in the saddle.

The rear uses a 12 × 142 mm thru-axle and flat-mount disc brakes with clearance for rotors up to 160 mm. The frame has two bottle cage positions, mounts for a rear rack and mudguards, and Di2 cable ports that can also be used for internal routing to a rear dynamo light. The threaded 68 mm bottom bracket shell and standard 27.2 mm seatpost keep several key standards simple.

Compared with the Brother Kepler, the Stroma is more road-oriented, with less tire clearance, a lighter carbon fork, and a more focused feel for asphalt and faster gravel. The Electric Blue version combines the vivid blue paint with white sections on the rear triangle, top tube, and fork – a fairly classic racing look on a frame built for many more days of the year than a traditional road bike.

Quick Specs

• Model: Brother Cycles Stroma
• Type: Steel frameset for road, all-road and fast gravel
• Color: Electric Blue
• Frame: Reynolds 725, heat-treated and double-butted main triangle, ED-coated
• Rear triangle: Reynolds 520/500
• Fork: Brother monocoque carbon fork with a tapered steerer tube
• Sizes: X-Small, Small, Medium, Large and X-Large
• Wheels: 700C
• Max tire width: 700 × 38 mm
• Max tire width with fenders: 700 × 32 mm
• Rear axle: 12 × 142 mm thru-axle, included
• Front axle: 12 × 100 mm thru-axle, included
• Brakes: Flat mount, max 160 mm rotor
• Headsets: ZS44/28.6 upper / EC44/40 lower, not included
• Seatpost: 27.2 mm
• Seat clamp: 30 mm, included
• Bottom bracket shell: 68 mm, ISO threaded
• Front derailleur clamp: 28.6 mm
• Max chainring: 50T single or 53/39T double
• Bottle cage mounts: 2 sets
• Mounts: Luggage racks and fenders at the rear, fender mounts on the fork
• Dynamo cable: Internal routing through the fork
• Di2: Cable ports in the frame
• Frame weight: Approximately 1.97 kg in size Medium
• Fork weight: Approximately 500 g with an uncut steerer tube