Brother Cycles Big Bro Frameset

Availability & Ordering
We list all framesets currently available from Brother Cycles as “in stock.” While we have a few on hand, most orders will be fulfilled via special order with approximately 14-day delivery.

To confirm ETA or any other questions, get in touch:
shop@bicyclejunction.co.nz | 04 385 2362

Brother Cycles Big Bro Frameset

Tough, versatile, and up for anything.

The Big Bro is Brother’s go-anywhere, carry-everything, ride-forever adventure frame. Whether you're strapping on lightweight bikepacking gear, loading up front and rear panniers for a world tour, or keeping it simple for weekend trail thrashing—the Big Bro is built to handle it.

Constructed from ED-coated 4130 chromoly steel and paired with a 100mm suspension-corrected steel fork, the Big Bro is tested and trusted on everything from the Scottish Highlands to the Silk Road Mountain Race.

Now with Boost spacing, it fits 27.5 x 3.0” or 29 x 2.6” tyres. Add in stealth dropper routing, triple mounts galore, sliding dropouts, and Rohloff compatibility—and you’ve got one seriously capable rig.

Frame Features

• Material: 4130 double-butted chromoly steel (ED coated)

• Fork: Chromoly unicrown fork, suspension-corrected (ED coated)

• Tyre Clearance: Up to 29 x 2.6” or 27.5 x 3.0”

• Dropouts: Sliding Boost 12x148mm (included) – geared or singlespeed

• Rohloff compatible: Optional dropout set available

• Brake Mounts: IS 51mm, 180mm max rotor

• Bottom Bracket: 73mm ISO threaded

• Seatpost Diameter: 30.9mm

• Seat Clamp: 33.1mm (included)

• Front Derailleur: 34.9mm high direct mount (adapter required)

• Headset: 44mm ZS44/EC44 (not included)

• Cable Routing: Full-length for brakes and derailleurs

• Mounts:

  • 3x bottle cage (including under downtube)

  • Triple mounts on fork legs

  • Rear rack and fender mounts

Chainring Clearance

• 1x: up to 38t

• 2x: up to 44/30t

• 3x: up to 48/36/26t

Weight

• Frame (M/18"): 2.60kg

• Fork (uncut, 300mm steerer): 1.37kg

Adventure-tested and expedition-approved.
From backcountry escapes to continent-crossing endurance rides, the Big Bro is the steel workhorse that keeps going—no matter what.