Brother Big Bro
Ultra classy adventure & trail bike
The Brother Big Bro is Brother Cycles’ all purpose, tough as nails, 29er adventure bike – built to take you well off the beaten track and beyond. Whether you’re running a lightweight bike-packing setup, front and rear panniers for a ’round-the-world’ tour or stripped back to thrash some forest trails the Big Bro can handle it all.
For 2025 the high quality steel frame has been upgraded, with new rear drop-outs, a UDH mech hanger and heat treated tubing, plus top tube bag bosses and additional rack bosses on the fork. Still with clearance for big volume tyres of course, delivering a ride quality that is simply outstanding and totally fuss free.
Like all Brother products the Big Bro has been rigorously tested out in the real world – prototypes were taken 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 bike-packing endurance races – the 4,418km Tour Divide from Canada to Mexico and the 1,710km Silk Road Mountain Race in Kyrgyzstan.
The frame is now made out from 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 inside and out. There’s clearance for big 29 x 2.6″ tyres or up to 3 inch tyres if you’d prefer to go 27.5+.
“every time I rode it, I returned feeling delighted by its handling and how much fun I’d had… Excuse the poetic license, but it’s a mountain bike that’s crying out to be ridden along grassy drover’s tracks in Mid Wales, or the historic, stony byways of England’s Lake District. It’s a Rough-Stuff Fellowship tourer, with a plus-sized twist. There are no airs or pretenses; aside, that is, from that lovely, eye-catching finish. It’s just a blast to ride.” Bikepacking.com
The Big Bro features stealth dropper routing, rack mounts, top-tube bag mounts, bottle mounts on the seat tube, down tube and under the down tube for an extra bottle or storage. The forks also feature 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.
“I quickly fell in love with this bike. It is refreshingly simple in design, stunning to look at and beautifully made. It just seemed to call out ‘ride me’ every time I looked at it” Singletrack Magazine
Frame Tubing: 4130 Heat Treated Chromoly steel – double-butted main triangle, ED coated frame
Brake Compatibility: 51mm IS disc brake mount, 180mm max rotor size
Frame Dropouts: Boost 12x148mm thru axle (included)
Gear Hanger: SRAM UDH type, full mount compatible
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 top pull or 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)
Guides: Full-length cable housing guides for derailleurs and brakes
Mounts: 3 sets bottle cage mounts on all sizes
Chainring Clearance: 48-36-26t triple, 44-30t double, 38t single
Weight: Medium (18″) frame 2.60kg, fork (300mm steerer) 1.37kg
Tested to ISO 4210 MTB standard
COLOURS
For summer 2025 Brother Cycles have introduced two classy new colourways – Swamp Thing and Stealth. Both feature the new metal head badge, and look stunning in the flesh!
Big Bro – Stealth Colourway
Big Bro – Swamp Thing Colourway
BROTHER BIG BRO
All Brother Big Bros start out as a bare frameset initially, for building up into a complete bike with suitable components of your choice.
Below are some example custom builds that we can offer ‘off the peg’ or use as a start point for further customisation.
Brother Big Bro CUES 11s – £1,749
Specification
FRAME: Brother Big Bro 4130 Heat Treated Chromoly, ED coated, UDH
FORK: Brother Big Bro 4130 Chromoly, ED coated
HEADSET: M:Part
BOTTOM BRACKET: Shimano BSA 73
SHIFTER: Shimano CUES U6000 11-speed
BRAKES: Shimano M200 Hydraulic Disc, RT26 6 Bolt 160/180mm rotors
FRONT DERAILLEUR: n/a
REAR DERAILLEUR: Shimano CUES U6000 11-speed, Shadow+
CRANKSET: Shimano CUES U4000 11-speed, 30T or 32T
CASSETTE: Shimano CUES LG400 Link Glide 11-50T 11-speed cassette
CHAIN: Shimano Link Glide HG-X LG500
HANDLEBAR: Ritchey Comp
GRIPS: Gusset Single File Lock-On grips
STEM: Ritchey Comp
SEATPOST: Ritchey Comp
SADDLE: Fabric Scoop Sport Radius
WHEELS: Oxford Evo Trail 29″ TLR
TYRES: Vittoria Barzo or Mezcal Sport TLR 29×2.4″
PEDALS: Half price pedals of your choice from leading brands, including Shimano, Look and Crank Brothers, available with every new bike order
EXAMPLE WHEEL OPTIONS:
- Halo Ridgeline II – add £109
- DT Swiss M1900 – add £179
COLOUR: Swamp Thing (Green) or Stealth (Black)
Brother Big Bro Deore 12s – £1,999
Specification
FRAME: Brother Big Bro 4130 Heat Treated Chromoly, ED coated, UDH
FORK: Brother Big Bro 4130 Chromoly, ED coated
HEADSET: M:Part
BOTTOM BRACKET: Shimano BSA 73
SHIFTER: Shimano M6200 Deore 12-speed
BRAKES: Shimano MT200 Hydraulic Disc, RT10 Centrelock 160/180mm rotors
FRONT DERAILLEUR: n/a
REAR DERAILLEUR: Shimano M6200 Deore 12-speed, Shadow+, SGS long cage
CRANKSET: Shimano M6200 Deore 12-speed, 30T or 32T
CASSETTE: Shimano M6200 10-51T 12-speed cassette
CHAIN: Shimano Deore
HANDLEBAR: Ritchey Comp
GRIPS: Gusset Single File Lock-On grips
STEM: Ritchey Comp
SEATPOST: Ritchey Comp
SADDLE: Fabric Scoop Sport Radius
WHEELS: DT Swiss M1900
TYRES: Vittoria Barzo or Mezcal Sport 29×2.4″ TLR
PEDALS: Half price pedals of your choice from leading brands, including Shimano, Look and Crank Brothers, available with every new bike order
COLOUR: Swamp Thing (Green) or Stealth (Black)
EXAMPLE WHEEL OPTIONS:
- Halo Ridgeline II – deduct £69
- Hope Fortus 30W-Pro 5 – add £119
Brother Big Bro XT 12s – £2,449
Specification
FRAME: Brother Big Bro 4130 Heat Treated Chromoly, ED coated, UDH
FORK: Brother Big Bro 4130 Chromoly, ED coated
HEADSET: Hope – choice of colours
BOTTOM BRACKET: Hope – choice of colours
SHIFTER: Shimano M8200 XT 12-speed
BRAKES: Shimano MT400 Hydraulic Disc, RT64 Centrelock 160/180mm rotors
FRONT DERAILLEUR: n/a
REAR DERAILLEUR: Shimano M8200 XT 12-speed, Shadow+, SGS long cage
CRANKSET: Shimano XT 12-speed – 28T, 30T or 32T
CASSETTE: Shimano XT 10-51T 12-speed cassette
CHAIN: Shimano XT
HANDLEBAR: Ritchey Comp
GRIPS: Gusset Single File Lock-On grips
STEM: Ritchey Comp
SEATPOST: Ritchey Comp
SADDLE: Ergon SR Allroad Mens/Womens
WHEELS: Hope Fortus 30W – choice of hub colours
TYRES: Vittoria Barzo or Mezcal Sport 29×2.4″ TLR
PEDALS: Half price pedals of your choice from leading brands, including Shimano, Look and Crank Brothers, available with every new bike order
COLOUR: Swamp Thing (Green) or Stealth (Black)
EXAMPLE WHEEL OPTIONS:
- Halo Ridgeline II – deduct £189
- DT Swiss M1900 – deduct £119