The Brother Cycles Stroma is an all-road frameset for year-round road riding, longer distances and rougher tarmac. A Reynolds 725 steel main triangle is paired with a full-carbon road fork, combining a traditional steel frame with modern thru-axle and flat-mount fittings.

Tyre clearance is up to 38mm without mudguards, or 32mm with full guards fitted. Mudguard eyelets, rear rack mounts and two bottle positions make the Stroma practical for commuting and distance riding as well as an unladen road build. Internal dynamo routing in the fork supports a lighting setup; the frame’s Di2 ports can also route a rear dynamo-light cable.

This listing is for the frame and fork, with complete-bike images supplied as build inspiration. Brother notes that the orange downtube branding is brighter in person than it appears in the photographs. Select your size and colour, then check the component standards and geometry below before choosing the remaining parts.

Technical specifications

• 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 38mm (32mm 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

Frame geometry

Available options

• Frame Size: Large, Medium, Small, X-large, X-small
• Colour: Black, Light Grey

Frame warranty

Brother provides a three-year warranty against manufacturing and material defects for the original purchaser, with proof of purchase required. Paintwork, normal wear, misuse and damage caused by neglect or modification are excluded. Refer to the manufacturer’s full warranty terms for the conditions that apply.