Brother Cycles Big Bro 2025 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.

Our all purpose, tough as nails 29er/27.5+ adventure frame; designed to take you well off the beaten track and beyond. Whether you’re running a lightweight bikepacking setup, front and rear panniers for a fully loaded ’round-the-world’ tour or just stripped back to thrash some forest trails the Big Bro can handle it.

New for 2025 // with the following updates the Big Bro is now an even more capable adventure frame – heat treated 4130 chromoly main triangle, new configuration sliding dropouts for a stronger and more reliable rear end, UDH full mount compatible rear mech hanger, top tube bag mounts and additional front rack mounts.

The frame is now constructed out of extra tough ‘heat treated’ 4130 double butted cro-mo tubing and comes with a 100mm suspension corrected fork, both with corrosion resistant ED coating applied. The Big Bro 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, multiple rack and bag mounts, a bottle mount on the seat tube and triple mounts on and under the down tube for extra bottles and storage. The Big Bro fork also features triple mounts to fit further bottle cages or Anything Cages.

The rear triangle features S-bend chainstays with replaceable alloy thru axle sliding dropouts for geared or singlespeed setups. These have been re-designed for 2025 to now feature a rail system for extra strength and reliability.

We now offer a Rohloff specific dropout set which makes the Big Bro compatible with the Rohloff 135mm Speedhub with OEM axle plate. See here for details.

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 many of the world’s toughest bikepacking endurance races – including the 4,418km Tour Divide from Canada to Mexico and the 1,710km Silk Road Mountain Race in Kyrgyzstan.