Brother Cycles Big Bro Frameset 2021 (Green)

The frame is made out of tough 4130 double butted cro-mo tubing and comes with a 100mm suspension corrected fork, both with corrosion resistant ED coating applied. For 2021 the Big Bro now features Boost spacing which means there’s clearance for big 27.5 x 3″ tyres or 29 x 2.6″ tyres if you’d prefer to go with a 29er setup. It features stealth dropper routing, rack mounts, bottle mounts on the seat tube, down tube and under the down tube for an extra bottle or storage. The forks also feature triple bottle mounts to fit further bottle cages or Anything Cages. S-bend chainstays with replaceable alloy thru axle sliding dropouts allow for geared or singlespeed setups.

Like all Brother products the Big Bro has been rigorously tested out in the real world – we took prototypes across the South Downs, through Snowdonia National Park and up to the Scottish Highlands. The Big Bro has since completed two of the worlds toughest bikepacking endurance races – the 4,418km Tour Divide from Canada to Mexico and the 1,710km Silk Road Mountain Race in Kyrgyzstan.
FEATURES
Tubing: – 4130 Chromoly steel – double-butted main triangle, ED coated
Brake compatibility; 51mm IS disc brake mount, 180mm max rotor size
Dropouts: Boost 12x148mm thru axle (included)
Seat post diameter: 30.9mm
Seat clamp diameter: 33.1mm (included)
Headset: 44mm, SHIS ZS44/28.6 upper, EC44/40 lower (not included)
Front derailleur clamp diameter: 34.9 mm high direct-mount (adapter available separately)
Bottom bracket shell: 73mm bottom bracket, ISO threaded
Maximum tyre clearance: 29″ x 2.6″, 27.5″ x 3.0″ (note: not all drivetrains allow for these maximum tyre clearances)
Fork : 4130 Chromoly tapered unicrown fork, ED coated. 15x110mm Boost thru axle (included)
Full-length cable housing guides for derailleurs and brakes
3 sets bottle cage mounts on all sizes
Chainring clearance: 44-30t double, 38t single
Weight: medium (18″) frame 2.60kg, fork (300mm steerer) 1.37kg
Tested to ISO 4210 MTB standard