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

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.