Big Bro

£625.00 Inc VAT

(Price for non-EU customers £520.83)

Our all purpose, tough as nails, 29er adventure frame – built to take you well off the beaten track and beyond. Whether you’re running a lightweight bikepacking 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.

The frame is made out of tough 4130 double butted cro-mo tubing and comes with a 100mm suspension corrected fork, both with corrosion resistant ED coating applied. There’s clearance for big 29 x 2.4″ tyres or up to 3 inch tyres if you’d prefer to go 27.5+. It features stealth dropper routing, rack mounts, bottle mounts on the seat tube, down tube and under the down tube for an extra bottle or storage. The forks also feature triple bottle 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.

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 two of the worlds toughest bikepacking endurance races – the 4,418km Tour Divide from Canada to Mexico and the 1,710km Silk Road Mountain Race in Kyrgyzstan.

Features

Frame Specs

FAQs

Features

Tubing: - 4130 Chromoly steel - double-butted main triangle, ED coated
Brake compatibility; 51mm IS disc brake mount, 180mm max rotor size
Dropouts: 12x142mm thru axle (included)
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 high direct-mount (adapter available separately)
Bottom bracket shell: 73mm bottom bracket, ISO threaded
Maximum tyre clearance: 29" x 2.4", 27.5" x 3.0"
Fork : 4130 Chromoly tapered unicrown fork, ED coated. 15x100mm thru axle (included)
Full-length cable housing guides for derailleurs and brakes
3 sets bottle cage mounts on all sizes
Chainring clearance: up to 48-36-26t triple, 42-28t double, 38t single
Weight: medium (18") frame 2.6kg, fork (260mm steerer) 1.25kg
Tested to ISO 4210 MTB standard

Big Bro technical drawing
SizeSmall (16)Medium (18)Large (20)xLarge (22)
Seat Tube (C-T)406mm457mm508mm559mm
Top Tube (C-C)556mm571mm595mm622mm
Top Tube (Effective)575mm595mm620mm645mm
Head Tube95mm100mm110mm125mm
Head Angle69.57070.570.5
Seat Angle73737373
BB Drop60mm60mm60mm60mm
Min Chainstay445mm445mm445mm445mm
Fork Length (A-C)483mm483mm483mm483mm
Fork Rake46mm46mm46mm46mm
Stack598mm605mm616mm630mm
Reach392mm410mm432mm452mm
Standover (mid top tube)782mm810mm840mm871mm
Wheelbase1083mm1098mm1118mm1144mm

How tight should I torque the bolts on my Big Bro sliding dropouts?

We recommend a max torque value of 24Nm for the 4 large M8 bolts which secure the sliding dropout plates on the Big Bro. Make sure to use a well fitting allen key socket so as not to round off the head of the bolt.

Are your frames guaranteed?

Our frames and bikes are fully guaranteed against manufacturing and materials faults or defects for 12 months from date of purchase. This guarantee does not cover items which are damaged through accident, misuse, wear and tear, neglect or those which have been repaired or altered by any other firm. Paintwork is not covered covered by this warranty, nor is any damage that happens to you or your other components as a result of any failure of one of our products.

This guarantee is only valid to the original customer and is non-transferable. We reserve the right to an independent opinion on whether the goods qualify for a refund. A dated proof of purchase must be provided before a warranty claim will be considered.

Can you build me a custom bike?

Sorry we don’t do custom builds, but you can contact one of our many stockists for assistance in building up a bike.

Where are your frames stocked?

You can see a list of shops where our frames are stocked here. If your LBS isn’t listed then ask them to get in touch with us about ordering a frame for you.

Where are your frames made?

Our frames are made in Taiwan. They are handmade using traditional brazing and welding techniques with the highest quality materials by a team of frame builders who have over 2 decades of experience. Each frame undergoes extensive quality and safety checks before it is shipped to us in the UK. Although built overseas our frames were carefully designed by us in London and are exclusive to Brother Cycles.