For the explorer who sees no trail, only horizon, the 2025 Surly Moonlander is your ticket to the edge of the map—and beyond. This is not merely an evolution of the fat bike; it is a complete re-imagining of what’s possible on two wheels . Featuring colossal 24 x 6.2-inch tyres—the widest found on any production bicycle—and Surly’s first-ever integration of a Pinion gearbox, the Moonlander is designed to “float” over sand, snow, rock, and tundra with an almost otherworldly composure . For the rider seeking a Large frame, this machine offers a stable, commanding platform for multi-day bikepacking expeditions or simply the most unforgettable ride on your local beach.
Frame and Fork
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Frame: Built to withstand the harshest environments on Earth, the frame is constructed from 100% Surly Chromoly Steel . The triple-butted main triangle and TIG-welded construction offer the perfect blend of strength, durability, and compliance. The geometry features a radically sloping top tube for maximum standover clearance—a crucial detail when navigating soft, unpredictable terrain where dabs are inevitable . An anti-corrosion E.D. coating protects the frame from the elements, whether salt spray or snow melt .
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Fork: The matching Surly Moonlander fork, also made from 100% Chromoly steel, tracks true through soft ground thanks to its 197mm x 12mm thru-axle dropout, ensuring precise steering and rock-solid stability .
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Adventure Ready: True to Surly’s ethos, the frame and fork are studded with countless accessory mounts, allowing you to bolt on racks, fenders, and cargo cages for epic, self-supported journeys .
Drivetrain
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Gearbox: The centerpiece of the Moonlander’s transformation is the Pinion C1.9 XR 9-speed gearbox . This German-engineered transmission is a sealed, oil-bath unit that operates independently of external contaminants. It offers a massive 568% gear range, requires minimal maintenance (oil changes only every 10,000km), and allows for shift-on-the-stop capability—a godsend when navigating technical, low-speed terrain .
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Control & Crankset: Shifting is managed by a simple and robust Pinion Twist shifter . The custom Surly Pinion crankset features a high-offset spider to provide the necessary chain clearance for the massive 6.2″ tyres .
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Chain: Power is transferred via a KMC EPT (Extreme Performance Treatment) chain, designed to resist corrosion and wear in the gritty, wet conditions this bike thrives in .
Cockpit and Finishing Kit
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Handlebars & Stem: The rider commands the trail from behind the Surly Terminal Bar, a steel handlebar known for its significant backsweep, providing an upright, comfortable, and controlled riding position ideal for long days in the saddle . It’s clamped by a 4-bolt Promax stem (70mm length on the Large frame) .
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Seatpost: A TransX YSP15JL dropper post with 125mm of travel is a standard feature, allowing you to instantly lower your center of gravity on descents or when traversing steep, slippery slopes .
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Saddle & Grips: Contact points are covered by a comfortable WTB Volt saddle and locking Velo grips for security and comfort .
Brakes
Wheels and Tires
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Tires: The undisputed stars of the show are the Surly Molenda 24 x 6.2″ tyres . With a footprint over three times wider than a standard mountain bike tyre, they provide unparalleled flotation. Riders can drop pressures as low as 4 PSI to effectively “paddle” through soft sand or snow, transforming impossible terrain into a ridable surface .
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Rims: These massive tyres are mounted on Surly Clown Royal 24″ rims, which are a staggering 100mm wide—a purpose-built foundation for the bike’s extreme footprint .
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Hubs: A unique feature is the use of matching Novatec 197mm x 12mm rear hubs on both the front and rear wheels. This provides ultimate redundancy on expeditions; if a freehub fails, the wheels can be swapped to keep you moving .
Sizing: The “Large” Fit
This size Large frame is designed to accommodate taller riders with confidence and stability.
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Rider Height: Designed for riders approximately 180cm to 190cm (5’11” to 6’3″) tall .
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Key Geometry (Size Large): The bike features a long 1114.8mm wheelbase and 450mm chainstays for planted stability, while the 608.3mm stack and 429mm reach create a spacious yet controlled cockpit .
Why This Bike?
The 2025 Surly Moonlander is a statement. It declares that adventure is not found on the beaten path, but in the places where the path disappears. This is a purpose-built tool for extreme soft-terrain exploration, bikepacking in the frozen north, or simply experiencing the sheer, grin-inducing fun of riding on surfaces that stop other bikes in their tracks . In size Large, it offers the perfect proportions for taller riders to harness this beast’s unique capabilities. It is, as one reviewer put it, “unquestionably the biggest bike which I have ever swung a leg over,” and it’s ready to take you to places you’ve only dreamed of .
