Brother Cycles Big Bro — Custom Build
The Brother Big Bro is built for going beyond the edges of the map — a tough-as-nails 29er/27.5+ adventure frame made to carry you well off the beaten track. Bikepacking, week-long forest missions, or just a fast local rip after work — the Big Bro handles it all with calm, capable confidence.
Our 2024 custom build takes this already-legendary platform and gives it the Bicycle Junction treatment. The frame is built from heat-treated 4130 double-butted Chromoly with an ED-coated finish for maximum durability, paired with a 100 mm suspension-corrected fork and Boost spacing for proper modern clearance. Run big tyres, load it with bags or racks, or strip it back for trail duty — it’s designed to adapt.
This build rolls on Wheelworks W:Three wheels, wrapped in Vittoria Mezcal 29×2.35 tyres for fast, reliable traction on everything from gravel to alpine singletrack. Shimano’s XT 1×11 drivetrain (11–46) keeps things simple and bombproof, while Shimano M5120 four-piston brakes deliver confident stopping power fully loaded or fully pinned. A Ritchey cockpit rounds out the build for long-distance comfort and control.
The Big Bro is the kind of bike you grow into — not out of. It’s carried riders across the South Downs, Snowdonia and the Scottish Highlands, and it’s proven itself on the Tour Divide and the Silk Road Mountain Race. This custom BJ build is ready for your version of that story.
Build Highlights
– Shimano XT 1×11 drivetrain, 11–46
– Wheelworks W:Three handbuilt wheelset
– Shimano M5120 four-piston brakes
– Ritchey bars, stem and seatpost
– Vittoria Mezcal 29×2.35 tyres
| Frame Size | Small (16) | Medium (18) | Large (20) | X-Large (22) |
|---|---|---|---|---|
| Seat Tube (C-T) | 406 mm | 457 mm | 508 mm | 559 mm |
| Top Tube (C-C) | 556 mm | 571 mm | 595 mm | 622 mm |
| Top Tube (Effective) | 575 mm | 595 mm | 620 mm | 645 mm |
| Head Tube | 95 mm | 100 mm | 110 mm | 125 mm |
| Head Angle | 69.5° | 70.0° | 70.5° | 70.5° |
| Seat Angle | 73.0° | 73.0° | 73.0° | 73.0° |
| BB Drop | 60 mm | 60 mm | 60 mm | 60 mm |
| Min Chainstay | 445 mm | 445 mm | 445 mm | 445 mm |
| Fork Length (A-C) | 483 mm | 483 mm | 483 mm | 483 mm |
| Fork Rake | 46 mm | 46 mm | 46 mm | 46 mm |
| Stack | 598 mm | 605 mm | 616 mm | 630 mm |
| Reach | 392 mm | 410 mm | 432 mm | 452 mm |
| Standover (29 × 2.25") | 782 mm | 810 mm | 840 mm | 871 mm |
| Wheelbase | 1083 mm | 1098 mm | 1118 mm | 1144 mm |
Custom Builds
Get Inspired
Feast your eyes on our Custom Build Gallery - every bike spec’d and built in the Bicycle Junction Workshop. From pinstriped cargo bikes for breweries to ground-up world tour machines, we’ve done it all.
Click below for inspiration, and get in touch to start building your own dream bike.