Brother Cycles Big Bro adventure bike frame kit

The rugged, all-terrain Big Bro adventure frame kit is designed to take you beyond the beaten path. Whether you're using a light bikepacking setup, loaded front and rear panniers for a world tour, or simply hitting forest trails, the Big Bro will deliver.

The frame is made from durable double butted 4130 chromoly steel and is fitted with a 100mm suspension fork , both with a corrosion resistant ED coating . The Big Bro now features Boost spacing, providing clearance for large 27.5 x 3" or 29 x 2.6" tires if you prefer a 29er setup. It includes an internal dropper post pass-through, luggage rack mounts, bottle cage mounts on the seat tube , on and under the down tube . The forks also feature triple eyelets for additional bottle holders or storage. S-shaped bases with replaceable sliding alloy legs allow for single-speed or single-speed configurations .

The Rohloff 135 mm Speedhub hub can be adapted to the Big Bro thanks to a set of specific dropouts for Rohloff.

Like all Brother Cycles products, the Big Bro has been rigorously tested in the real world, with prototypes taken across the South Downs, Snowdonia National Park and as far as the Highlands of Scotland. The Big Bro has since completed two of the world's toughest bikepacking endurance races: the 4,418km Tour Divide from Canada to Mexico and the 1,710km Silk Road Mountain Race in Kyrgyzstan.

Technical characteristics:

• Frame tubes: 4130 chromoly steel - double butted main triangle, ED coating
• Brake Compatibility: IS 51mm disc mount, maximum rotor size 180mm
• Dropouts: Boost 12x148mm with thru axle (included)
• Seat tube diameter: 30.9 mm
• Seat clamp diameter: 33.1 mm (inclusive)
• Headset: 44mm, SHIS ZS44/28.6 upper, EC44/40 lower (not included)
• Front Derailleur Clamp Diameter: 34.9mm, Direct Mount High (Adapter available separately)
• Bottom bracket: 73mm, ISO thread
• Maximum tire clearance: 29" x 2.6", 27.5" x 3.0" (note: not all drivetrains allow these maximum clearances)
• Fork: Unicrown tapered 4130 chromoly fork, ED coating, Boost 15x110mm thru axle (included)
• Full-length cable housing guides for derailleurs and brakes
• 3 sets of wine rack brackets on all sizes
• Chainring clearance: double 44-30t, single 38t
• Weight: medium frame (18") 2.60 kg, fork (300 mm head tube) 1.37 kg
• Tested according to ISO 4210 MTB