Review: Brother Cycles Big Bro

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Sometimes, simplest is best.

As the sport of mountain biking continues to fragment into more and more niches, it’s worth looking back to when it all began. In those early days, there weren’t downhill bikes, or enduro bikes, or trail bikes, or even full suspension bikes. There were only mountain bikes – pure and simple mountain bikes.

With knobbly tyres, wider handlebars and lower gearing, mountain bikes were simply about about exploring off the beaten path, away from busy city streets and bitumen roads, and out into the wilderness away from it all. Going places that road bikes could not go. Tackling singletrack that touring bikes could not tackle. Pointing to a place on a map and saying “Let’s do it! Who’s bringing the coffee?”

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
All loaded up: The Big Bro from Brother Cycles.

While it may be far more modern in numerous ways, the Brother Cycles Big Bro embodies the same spirit of those early mountain bikes. It doesn’t have an expensive carbon fibre frame or a fancy suspension design. Heck, it doesn’t have suspension at all. But that isn’t the point with this bike – this is pure and simple; a bike built for off-road adventures.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Founded in 2010, Brother Cycles is based in London.

Introduced late last year, the Big Bro is the first 29er mountain bike from London-based Brother Cycles. The Brother Cycles brand originally launched in 2010 with a focus on high-quality steel frame fixies and urban warfare machines. Started by brothers Will & James, Brother Cycles has steadily increased its range over the years, with more dirt-curious models since joining the line.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The Big Bro is the brand’s 29er mountain bike. But it’s got a load of tricks up its sleeve.

The Big Bro is the most capable of the lot. It features a tough steel frame that’s ready for a’punishing, proper tyre clearance for up to 29 x 2.4in tyres, and geometry tailored towards singletrack meandering. It’s got lugs for nearly every pannier, mudguard and mounting accessory you can think of, and as such, it slots right into the off-road bikepacking category alongside other bikes such as the Genesis Longitude and Surly Karate Monkey.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
A matching rigid fork is included with the frame, and has mounts for EVERYTHING.

As a rider who predominantly resides in the full suspension trail bike camp, this test was (in theory) going to be a stroll down an unfamiliar road. And yet in many ways, riding the Big Bro would prove to be more of a journey that would bring me back around full circle to where mountain biking all started for me.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The Big Bro in it’s natural environment.

The Bike

When the Big Bro first turned up at Singletrack Towers, there wasn’t a soul in the building who didn’t fall in love with it’s stunning custom build. Put together by the bling-merchants at Soho Bikes in London, our Big Bro frame came absolutely dripping with the hottest bling from Hope, Renthal, SRAM and Brooks. There literally wasn’t one part that didn’t scream ‘high performance chic’.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Our Big Bro test bike came to us with a souped-up bling kit courtesy of Soho Bikes. Note: hand model’s own.

Constructed from 4130 cromoly steel, the Big Bro frame is simple, elegant, and built for longterm durability. The front triangle uses double butted tubes, which helps shave some weight in the steel tubing by thinning out the walls in the centre of each tube. It also increases the frame’s ability to filter out vibrations. The rear triangle employs more slender tubes with subtle curves that help to increase tyre clearance while offering some ‘spring’ to the back end of the bike.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Good ol’ 4130 cromoly steel tubing.

The frame is painted in a subtle Stone Green colour (I’d call it eggshell blue), and a matching cromoly fork is included in the package. The fork is suspension corrected, so technically you could fit a 80mm travel fork on the front without cause for concern. The problem being that there ain’t too many 29er suspension forks designed with 1 1/8in steerer tubes anymore, so that kind of limits your upgrade potential.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
And a good ol’ threaded bottom bracket shell.

To be honest though, we don’t envisage too many Big Bro riders wanting to elect for extra squish. There’s generous room for decently wide 29er tyres, and you could easily squeeze a 2.6in wide tyre into the widely-spaced fork legs. Either way there’s loads of mud clearance, and the fully rigid setup offers numerous durability benefits for those who favour fewer moving parts.

Geometry wise, the Big Bro isn’t exactly pushing boundaries. It’s standard fare for a rigid 29in mountain bike, with a 71-degree head angle and a 73-degree seat angle. However, our Medium test bike puts out a decent 595mm effective top tube length, which helps to increase the overall reach and wheelbase length for added stability.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Neat modular sliding dropouts allow for geared or singlespeed setup.

Speaking of, the rear centre sits at a generous 445mm length in its shortest position, though that extends by nearly an inch thanks to the adjustable dropouts. Using four large stainless steel bolts to lock down the alloy dropouts to the steel frame, this adjustable design offers the ability to tweak the handling by altering the overall chainstay length. It also offers up the capability to go singlespeed, with in-built tensioners offering extra security.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Simple 135mm quick release dropouts.

As for the rest of the Big Bro frame, it’s refreshingly simple. There’s a 73mm threaded bottom bracket shell, a 1 1/8in headtube, and 135mm quick release dropouts. All cabling is external, and you can fit a front derailleur if you wish. There’s even clearance on the chainstay to fit a large triple chainset of the 26/36/48t variety.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
More lugs out back for bolting on a pannier rack.

Where the Big Bro separates itself from many other steel 29er hardtails on the market however, is in its provision for nearly every kind of bikepacking accessory you can think of. There’s mounts for mudguards, pannier racks, numerous water bottles, and Anything Cages – both on the frame and on the fork legs. Basically if you want to fit some kind of bag or cage to this bike, chances are it’ll take it.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Lovely Brooks saddle and carbon Hope seatpost.

I won’t dwell on the build of the Big Bro too much, because as I mentioned before, it’s been designed by Soho Bikes to be a jawdropper. And drop jaws it most certainly has. However, highlights that I must note include a beautiful Hope AM stem, a thoroughly comfortable Brooks Cambium saddle, and a slick 1×11 drivetrain complete with Hope’s own wide-range 10-44t cassette.

All up (with inner tubes but without pedals), the medium sized Big Bro came in at 11.2kg. Shortly after weighing it, I setup the rims with Stans Yellow Tape, pulled out the tubes, added valves and sealant, and dropped just over 200 grams off the total bike weight.

But enough of numbers. How does the Big Bro ride? How did it handle the variety of dirt roads, bridleways and singletrack trails around Calder Valley and beyond?

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Heading up on the Big Bro.

The Ride

First thing’s first. Those Renthal Carbon handlebars are trick, but they were too wide for me on a bike like the Big Bro. I swapped them for a set of alloy Ragley Wiser bars, with a slightly narrower 760mm width and a touch more rise at 25mm. The subtle cockpit change made a world of difference to comfort, reducing the lean over the grips and pushing my shoulders further upright.

Unlike some of the earlier rigid 29er mountain bikes I rode years ago, the Big Bro benefits from a much longer top tube. Not Mondraker Forward Geoemtry long, but long for this type of bike. This mates well to the 50mm Hope stem and the wide bars, providing a comfortable and secure stance over the front wheel. The overall riding position is comfortable, without going too far into the super-upright touring style. With the thin lock-on grips, smooth disc brake levers, and broad bars, it still has that familiar feel of a proper mountain bike.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The riding position on the Big Bro is comfortable, though it’s more mountain bike than touring bike.

Once I’d taped the Hope rims tubeless, I swapped in a set of Bontrager XR3 2.4in wide tyres to add a little more cushioning. With pressures set around 17-19psi, the versatile Bonty rubber provided a welcome boost to the Big Bro’s suppleness over packhorse trails and rooty wooded singletrack. Because of the lack of any actual suspension, tyre pressure is crucial to getting maximum comfort and grip out of the Big Bro, so pay attention with your tyre gauge. And unless your riding is going to encompass a whole load more bitumen, I’d recommend going as wide as you possibly can.

In the four months we spent together, the Big Bro carried me along on many an adventure. In some of our more testing moments, we plugged our way through hub-deep mud in the Pennines, and pushed hard against ravaging head winds on the moors. And in more positive times, we traversed across hill and dale on the South Downs Way under glorious sunshine, and darted around the smoother blue lines at numerous trail centres. But whether it was the daily bitumen grind, a post-work exploration mission on the local bridleway network, or a long distance weekender trip, the Big Bro proved a reliable companion that quietly went about its business without complaint.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Whatever the surface, the Big Bro just gets on with it. So versatile.

The 1×11 drivetrain proved quiet and efficient, though there were occasions where I would have liked a little more top-end speed for winding up on open dirt roads of a gradual descending gradient. Likewise, some of our local singletrack is particularly steep on the ups, and a smaller chainring would have been eagerly welcomed by my knees. That said, the simplicity of the 1x drivetrain is appealing, as are the stunningly clean lines it affords. And with the chassis offering good rigidity, the Big Bro never complained when I left the saddle to dig in on steeper upwards pinches.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
With its sharp geometry and rigid fork, the Big Bro weaves around bends crisply and quickly.

For laying down the power, the Big Bro responds well under both your pedalling and turning directions. One thing I did experiment with was the chainstay length. For part of the test period I slammed the rear tyre in as short as possible, and enjoyed sharper handling as a result. With the rear tyre tucked in, the Big Bro felt more agile, and on smooth forestry-type singletrack, it was an absolute joy to weave in and out of corners around trees. With more stability and traction than a cyclocross bike, but more responsiveness and efficiency than a hardtail or full suspension mountain bike, it was on these types of trails that the Big Bro sung its best tune. In these moments, it kinda felt like I was riding my first mountain bike – except this one was faster, more stable, grippier and equipped with far, far, far better brakes.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The rougher the trail however, the more your knees and elbows have to become the suspension for the bike.

Get the Big Bro onto rougher trails however, and the rigid frame and uncompromising fork offers minimal forgiveness. Because there is no suspension, you have to become the suspension. So stand up, bend those elbows and knees, and let the bike flow beneath you.

The steep 71-degree head angle keeps steering quick, and when bouncing around rocky downhills, it can be a little too quick. You’ll have to retain a sharp mind in such scenarios, but with careful line choices, steady brake modulation and a loose body position, you’ll be surprised at what you can pick your way down. Perhaps slacker geometry would open up the Big Bro’s descending capabilities, but it would come at the expense of its nimble attitude on smoother wooded singletrack. Swings and roundabouts and all that.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Choose your lines carefully and watch the brakes, and the Big Bro will descend down a lot of stuff you might not expect it to.

For the latter part of the test period, I readjusted the dropouts into the longest position. The difference was instantly noticeable, with the Big Bro feeling just a little more chilled than previously. This was great for adding stability on rougher trails, where some of the sting was taken out of impact strikes when ploughing the rear tyre into rock ledges. It was also the default position I used whenever I was carrying gear. Adding extra weight to a bike requires a different approach to geometry and frame construction, with the bike needing to be capable of accepting higher loads. With bags, water and camping gear strapped on, the Big Bro had no difficulties adapting to the multi-day setup. Just a little more tyre pressure to handle the extra weight, and away the bike went, off into the distance towards our end destination.

And really, this is where the Big Bro’s strengths are at. Sure it rides well as a mountain bike on its own, but with all of the extra add-ons, this is a bike that surely deserves to be loaded up, with a map board on the handlebars and a couple of days of freedom in front of it.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
But it’s when the Big Bro is loaded up with gear and set course for adventure where its strengths really shine.

Durability Notes

Given the top-notch build, there were few problems I ran into through testing on the Big Bro. The gears performed flawlessly, the brakes were smooth and silent, and there were no ticks, clicks or annoying creaks that developed over time. Certainly something must be said for avoiding press-fit bottom brackets and internal headset bearings. Oh, and I’m a big fan of full-length external cable routing too.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The carbon seatpost is lovely, but I swapped it with an alloy post to use with heavier duty seat bags.

While the carbon handlebar and seatpost were beautiful additions to the build, they were less practical for bikepacking. To avoid damage, I swapped in an alloy seatpost and handlebar to offer sensible compatibility with a seat and handlebar bag.

Oh and a somewhat obvious but simple point of advice would be to fit a chainstay protector to silence chain slap and to reduce paint damage.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
The Big Bro doesn’t need thru-axles, but many modern wheels and hubs are electing for the thru-axle standard.

Three Things That Could Be Improved

  1. A 44mm head tube for improved compatibility with suspension forks for those that want them.
  2. Thru-axles. Not because the chassis needs more stiffness, but purely for compatibility reasons to open up more wheel and hub options.
  3. 27.5+ compatibility. While 27.5in wheels will fit in the Big Bro, there’s not quite enough clearance to get in a 2.8in tyre in the back. For a frame as versatile as the Big Bro, multi-wheelsize options would take it to a whole other level.
big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
I barely touched the sides of what gear the Big Bro can take.

Three Things What We Loved

  1. The simplicity. No pivots to worry about, no need for fork servicing, and no creaks and groans to ruin your riding tranquility.
  2. Adjustable dropouts. Offers an easy conversion to singlespeed, as well as the ability to change up the geometry.
  3. This bike has ALL OF THE MOUNTS. Seriously, there’s not much you can’t mount to this bike, and that makes it super easy to setup for bikepacking.
big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
Long distance off-road touring is this bike’s forte.


A simple, tough and well put together 29er mountain bike that has a thirst for adventure. The Big Bro isn’t a hardcore mountain bike, and it isn’t a touring bike – it takes on the grey area somewhere between the two. By drawing from both genres though, Brother Cycles has created a highly versatile bike that is just as happy turning over soil in the woods as it is clocking up miles. And between adventures, it’ll double-duty as a tough commuter bike too.

big bro steel rigid adventure camping mountain bike bikepacking wil calderdale
I had a habit of running into views like this while riding the Big Bro. It’ll do that to you.

Brother Cycles Big Bro Specifications

  • Frame // 4130 cromoly steel
  • Fork // Brother Cycles 4130 cromoly steel unicrown
  • Hubs // Hope Pro4, 100mm QR Front & 135mm QR Rear
  • Rims // Hope Tech XC 29er, 32h
  • Tyres // Schwalbe Nobby Nic EVO Pacestar 2.25in
  • Chainset // Hope Crankset & BB w/36t chainring
  • Rear Mech // SRAM XX-1, 11-Speed
  • Shifters // SRAM XX-1, 11-Speed
  • Cassette // Hope 10-44t, 11-Speed
  • Brakes // Hope Tech 3 X2, 180mm Front & 160mm Rear
  • Stem // Hope AM 50mm
  • Bars // Renthal Fatbar Carbon, 780mm Wide, 10mm Rise
  • Grips // Santa Cruz Palmdale Lock-On
  • Seatpost // Hope Carbon, 27,2mm x 350mm
  • Saddle // Brooks Cambium
  • Size Tested // Medium
  • Sizes available // Small, Medium, Large, X-Large
  • Weight // 11.2kg (24.64lbs)

Review Info

Brand:Brother Cycles
Product:Big Bro
From:Brother Cycles,
Price:£499 (frame & fork)
Tested:by Wil Barrett for 4 months

Comments (0)

    Sounds exactly like my El Mariachi. Glad someone else is making a steep angled bike now that Salsa stopped.

    Looks good. Now, a couple of questions: is it possible to fit conventional cycle touring racks front and rear? Also is it possible to build it up with bottom of the range shimano items? The reason for the latter is that riding in remote areas I like to have components that even the most basic and remote bike shop can replace. I have a couple of big cycle journeys in Iceland in mind. I backed off one as it was not rideable on 35mm touring tyres (oh and bad weather too) and I need a bike that will take tyres at least 50mm across.

    @molgrips – YES! That was the other frame I was trying to remember! Shame they don’t make the El Mariachi frame any more 🙁

    That said, while the El Mariarchi and Surly Karate Monkey have similar geo and ride qualities to the Big Bro, they don’t have quite the same number of mounting options for things like racks, cages and mudguards. The Big Bro has been designed to be quite a bit more versatile for bikepacking and off-road touring.

    @fatoldman – you bet! There are mounts on both the frame and fork for conventional touring racks. On the fork, you have the option to fit either a traditional low-rider style rack, or a porteur-style rack.

    As for building the frame up with bottom of the range Shimano items, ultimately you can build up the frame with whatever you like! The Big Bro only comes as a frame and fork package, so you can spec it out with whatever components you choose.

    Hope that helps, but give me a shout if you’ve got any more questions!



    Really good review Wil.

    Sounds like the sort of bike I was looking for when I bought my KM Ops.

    I was quite excited by the bike until I saw the sliders. With the multiple options for swinging dropouts or PF30/BEER EBB’s or standard EBB’s, out there, I never understand why builders use the ‘barnicle’ slider on their frames. It’s a bit like putting a VW Beetle roof on an Aston Martin.

    Aside from that, it looks to be a quite a capable and fun daily rider and bikepacking rig. However, for bikepacking, I’d definitely put on a bendy/alt bar of your choice (who am I kidding, I haven’t used a straight bar for a decade). Far more comfortable for long days of riding. Also, fewer wrist & hand issues for many folks.

    How does it compare to a 2017 Genesis longitude for example? I picked up a big bro frame in my lbs but bought the longitude in the end as it took 27.5+ wheels as well. I’m loving the longitude, it’s so simple and reminds me of my first specialized hard rock from 1989.

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