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The latest addition to the Rå lineup, the Bergsra is a 165mm rear, 170–200mm front enduro bike built to handle big terrain without fuss. Compatible with 29" or mullet setups and dual crown forks, it features adjustable geometry, chainstay length, and leverage ratio—offering a versatile, highly tunable platform. Designed for everything from bike park laps to enduro racing or just fast trail riding, it’s the result of five years of development, six full prototypes, and countless refinements along the way.

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Every detail has been tested, refined, and rebuilt through riding and obsession — not as a finishing touch, but as the foundation of everything this bike is built to do.

RA Bergsra
RA Bergsra
RA Bikes RAF kit with modular dropouts and assembly tools

The Bergsra frame is packed with precision-engineered details to enhance your ride. Easily adjustable modular dropouts for chainstay tuning, along with simple kinematic flip chips for meaningful ride feel changes. A main pivot with ultra-low maintenance bearings and replaceable ISCG tabs ensure reliable performance. The corrosion-resistant polyester seat tube liner minimizes maintenance, while accessible linkage bearings and a service-friendly design keep things simple.

Custom steel mountain bike frame being TIG welded by hand
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  • BERGSRA

    Enduro / Big Mountain / Gravity / Bike Park

    Pronounced: "Berg-Srah"

    High above the forests, in the stone and snow of the mountain itself — that’s where the Bergsra lives.

    Drawn from Norse folklore, Bergsra (or Bergsrå) was the guardian spirit of the mountain — something ancient, watchful, and powerful. Not just living in the mountain, but of it.

    This, RA’s longest travel frame. Designed for serious terrain, from enduro race stages to alpine ridge lines and heavy bike park laps. It’s stable, confident, but also precise, calm, and tuned to carry speed through the rough.

    It wasn’t built just to survive the mountain.
    It was built to feel at home in it.

  • More Than Steel

    RA isn’t just another boutique brand welding round tubes into a frame. It’s the product of years spent chasing a feeling — one I couldn’t buy, so I built it instead.

    I started in 2017 with a few hand tools, a corner of a freezing shed, and zero budget. No investors, no shortcuts. Just an idea I couldn’t shake and a stubborn refusal to settle for “good enough.” I didn’t come into this from design school or marketing — I came in through riding. A lot of riding. I’ve raced, crashed, pushed past the edge, and kept going. I know how a bike should feel — and more importantly, how it shouldn’t.

    So I taught myself everything. Machining, welding, CNC programming, fixturing, stress analysis, geometry theory. Not from books — from trying, breaking, and trying again. I didn’t want to rely on catalog parts or pre-made “framebuilder kits.” If something didn’t exist, I designed and built it. If it broke, I figured out why and made it better. These bikes have been tested, broken, rebuilt — over and over — until they didn’t.

    "There are no Chinese whispers here. No rider feedback to designer to engineer to production manager to factory to accountant. It’s just me."

    I’ve done 36-hour shifts in the workshop, wired on stubbornness and tea. I’ve had months where I couldn’t afford a new gas bottle for the welder, so I machined small parts until I could. I’ve chased tolerances in the thousandths, fought with warped tubes at 2AM, and questioned the whole thing more times than I’d admit out loud. When the prototype cracked. When the mill kicked and snapped an Endmill I couldn’t afford to replace. When people told me — kindly or not — that it would never be more than a hobby.

    But that feeling — that moment when it all works — it never let go.

    These tubes carry stories long before they ever became part of a bike. Profiles developed decades ago — for aircraft wings, race car chassis, suspension arms — because they worked.

     

    Some of those shapes were born in the arms race of early 20th century warfare, others in motorsport’s golden age. The top tube on the Bergsra? Originally developed for the Maserati 250F. Proven profiles from places where failure wasn’t an option — a profile refined for strength, lightness, and feel long before carbon and computer models took over.

    Still drawn today, still formed by a small handful of UK craftsmen using original tooling over a century old — the same tooling used for aircraft and racing icons that came long before bikes like this were even imagined.

    But this isn’t nostalgia. This isn’t retro. This isn’t steel for the sake of being different.

    This is steel chosen, shaped, and tuned with intent — to flex where it should, to hold its line when things get rough, and to feel calm when everything else is moving.

    Stiff where it needs to be. Compliant where it matters. Balanced. Planted. Alive.

    It’s steel, yes. But it’s the kind of steel that carries stories in every profile, every bend, every detail — and it's been pushed a lot further than most builders are willing to go. Not to prove a point. Not to follow fashion. But because I need to know.

    Because I want to ride it harder, push it further, and still trust it to bring me home.

    "This isn’t built for #steelisreal. It’s built for the ride."

    And I didn’t get here alone.

    My family have backed me from the very beginning — not just in words, but with real belief, real support, and everything they could give. They never asked “why,” only “how can we help?” And I’ve leaned on that more times than I can count.

    Friends didn’t just cheer from the sidelines — they rode early prototypes down serious trails, gave honest feedback, and took a chance when I had nothing but a raw frame and a promise. Some were the first to buy frames when I needed it most. Others chipped in with parts, tools, or just a hand when something heavy needed lifting or a problem needed solving.

    People in the industry — builders, riders, engineers and even the biggest corporations — gave me time, advice, encouragement, or opportunities they didn’t have to offer. And the MTB community as a whole… obsessive, passionate, generous to the core — they’ve welcomed me in, challenged me, and kept me going when the self-doubt crept in.

    I’ve built these frames, yes — but I’ve also been lifted by good people, every step of the way. And I’ll never forget it.

    This isn’t a sales pitch. It’s a note from the shed. From the edge of the map.


    From someone who couldn’t find what they wanted, so made it themselves.

    If any of that speaks to you — You’re probably the kind of rider I’m building for.

  • Travel Rear/Front: 165mm / 170-200mm
    Wheel Size: 29 Front - 29 / 27.5 Rear
    Max Tyre Width: 29 X 2.5
    Rear Hub: 148x12mm
    Drivetrain: 1X 52/55mm Chain line, SRAM UDH
    BB: 73 mm BSA - Replaceable ISCG05 Tabs
    Brake Mount: 200mm rear post mount, 220mm MAX
    Seat Post Diameter: 34.9mm / 38.5-39mm Clamp
    Cable Routing: Internal Cables. External rear brake.
    Rear Shock: 205x65mm Trunnion - 8x25mm hardware
    Fork Compatibility: 170-200mm + Dual Crown
    Leverage Ratio: Adjustable, independent of geometry
    Headset: Straight ZS56/ZS56


     

    TECHNICAL SPECIFICATIONS

    Beneath the sleek design of the Bergsra lies a wealth of obsesive details. From the highly tunable suspension platform to the easy to use internal cable routing, every detail has been carefully considered to provide a top-tier riding experience. Whether you’re adjusting the leverage ratio, changing the chainstay length and geometry or swapping between 29” and 27.5” rear wheels, the Bergsra is built to adapt, ensuring that it meets the demands of any trail.

  • Geometry 170mm Fork
    S
    M
    L
    XL
    Head Angle
    63.5°
    63.5°
    63.5°
    63.5°
    Seat Angle Effective
    79°
    79°
    79.6°
    79.6°
    Reach
    445mm
    465mm
    485mm
    505mm
    Stack
    628mm
    636mm
    645mm
    655mm
    Wheel Base (435/440mm CS)
    1227mm
    1252mm
    1281mm
    1305mm
    Front Center
    795mm
    817mm
    841mm
    865mm
    Axle to Crown (170mm ZEB)
    586mm
    586mm
    586mm
    586mm
    Offset (For refference)
    44mm
    44mm
    44mm
    44mm
    Trail (750mm OD Tyre)
    137mm
    137mm
    137mm
    137mm
    Bottom Bracket Drop 29 F+R
    30mm
    30mm
    30mm
    30mm
    BB Height (750mm OD Tyre)
    345mm
    345mm
    345mm
    345mm
    Seat Tube Length
    410mm
    420mm
    435mm
    435mm
    Head Tube Length
    100mm
    110mm
    120mm
    130mm
    Chain Stay Length
    435mm - 445mm - 455mm
    435mm - 445mm - 455mm
    440mm - 450mm - 460mm
    440mm - 450mm - 460mm
    Effective TT Length
    567mm
    590mm
    603mm
    625mm
  • RA Bergsra leverage ratio, anti rise, anti squat
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    Modular Dropouts - transmision compatible

    The frame uses modular dropouts that offer +10mm or +20mm chainstay length adjustment, while remaining fully compatible with the Universal Derailleur Hanger (UDH) and SRAM Transmission systems.

    Swapping dropouts takes less than five minutes — and thanks to the coaxial brake mount, there’s no need to realign the caliper. Quick, simple, and precise. Built to adapt as fast as you do.

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    Flip Chip Functionality

    A simple flip chip lets you switch between 29" and 27.5" rear wheels without affecting suspension kinematics or core geometry. A second “mid-position” chip refines the setup:

    With a 27.5" rear wheel, it runs in the lower, slacker setting.
    With a 29" rear wheel, it runs in the higher, steeper setting.

    This gives a 5mm bottom bracket shift and a 1° head angle change — without compromising suspension feel or ride balance.

    It’s a subtle but powerful way to tune geometry to your setup:
    Offset the increased stack of a 200mm dual crown fork by running the lower setting and a steeper headset. Or, set it up as a sharp, trail-capable 29er with quicker handling and more pedal clearance.

    Real adjustment, real effect — without unintended side effects.

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    Replaceable ISCG-05 Tabs

    The frame includes replaceable ISCG tabs mounted on a stainless steel splined interface. This adds protection in case of impact and makes the system easy to service.

    Once your chainguide offset is set, the entire guide and tab unit can be removed by simply undoing the BB cup — no need to re-stack fiddly washers each time. Quick to install, easy to live with, and built to take a hit.

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    Advanced Main Pivot System

    The main pivot uses 41mm angular contact stainless bearings with a preloaded compression collet arrangement. This eliminates any potential play. 

    Additionally, there’s an extra seal before the bearings to ensure ultra-low maintenance. 

    This setup allows for quick and easy servicing, with only three bolts needed to remove the rear triangle - without removing the cranks.

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    Cable Routing

    Our frames use internally routed cables with Nylon guide tubes that are bonded into stainless ports. This keeps the weather out, prevents cable rattle, & makes cable installation straightforward, contributing to a clean & quiet ride. With the exception of the rear brake which is externally routed for ease of maintenance. The rear brake can also be routed on either side of the head tube for left or right rear brake prefferences.

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    custom engraving

    Every frame can be subtly customised with engraving on the bottom bracket shell and top tube accessory plate. Whether it’s a name, number, phrase, or something personal — it’s a small mark that makes the bike unmistakably yours. Built and finished with meaning.

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LIFETIME WARRANTY

We stand by our craftsmanship. The Bergsra comes with a lifetime warranty, so you can ride with confidence knowing we’ve got you covered. In the event of a crash, our fair and transparent replacement service ensures you're not left out of pocket. We also maintain long-term back catalogue support, meaning parts and service will be available for years to come.

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FINISHING

All frames are powder coated for a tough, lasting finish, with a carefully selected range of standard colours designed to suit the frame’s aesthetic and function. Custom finishes are available on request for those after something more personal, and we’re happy to discuss options directly. For added protection, factory-fitted PPF kits are also available.

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STAINLESS STEEL & PRECISION MACHINING

Exposed, unpainted surfaces are made from stainless steel, offering long-term durability and corrosion resistance. Critical areas like the main pivot shell and linkage mounts are precision-machined after welding to guarantee exact tolerances and alignment.

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COAXIAL BRAKE MOUNT

Built around a 200mm direct post mount, the coaxial brake mount aligns precisely with the hub axle face, keeping the caliper perfectly centered on the rotor — eliminating twist, misalignment, and the need for facing.

Because the mount is coaxial, you can adjust chainstay length or remove the rear triangle without touching brake alignment. Everything stays dialed. Less time in the stand, more time riding.

3D Printing

3D printing is used for the Chainstay yokes, guided by strict criteria. Printed parts are only considered if they offer multiple benefits—such as reducing part count, integrating features, improving strength, decreasing weight, or simplifying manufacturing. Being trendy isn’t one of them!

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Dual Crown Compatible

With a straight ZS56 headtube ready for angle and reach-adjust headsets, along with a crossbraced gusset and reinforced top tube designed to withstand the impacts of dual-crown forks, the Bergsra is bike park and superenduro ready.

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ADJUSTABLE LEVERAGE RATIO

The lower shock mount features a 4-position flip chip, offering a 10% change in leverage ratio for an instantly noticeable difference in ride feel. Switching from a progressive setting for bike park hits to a more linear tune for natural singletrack takes less than a minute. Designed to work seamlessly with both coil and air shocks, this adjustment is completely independent of geometry.

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FLOATING BRAKE MOUNT

Part of thr RAF-KIT upgrade, the floating brake offers tuneable braking characteristics, with a two-position forward mount providing either 60% or 40% anti-rise. It’s designed to work seamlessly with the modular dropouts and adjustable chainstay lengths, all while using a standard rear hub and requiring no special tools. Mount points also allow use of the seat stay boss from the fixed brake adapter—ideal for quick back-to-back testing.

FORMED TUBES

Tubes are formed in the UK by motorsport and aerospace suppliers, using shaping techniques developed over decades. From aircraft wing ribs to modern chassis tubing, these methods help fine-tune ride feel through careful control of stiffness and compliance. From subtle ovalising to joint shaping, the result is a frame that feels responsive, durable, and built for real-world riding.

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Designed for Serviceability

From day one, the Bergsra was built to be easy to live with. All frame hardware is oversized and made from high-spec materials—titanium, 7075-AL, and stainless steel—for strength, durability, and long-term reliability. Most fasteners use standard 5mm or 6mm Allen keys, so there’s no rummaging for niche tools mid-service.

Linkage bearings are easy to remove and refit thanks to a split design that eliminates awkward press fits, and key areas are sealed with O-rings to keep small parts in place and the rebuilds frustration-free.

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The Rå Kit – Each frame comes with a pro-grade hard case. Complete with custom-cut foam inserts. Inside, you’ll find the full set of modular dropouts, the mid position geometry chip, spare small parts, and a complete set of linkage bearings along with the tools to press them in and out. 

There’s also space for other small parts like suspension tokens. It’s everything you need, all in one place—an industry-first level of support and attention to detail.

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