The Surly Moonlander has just set a new maximum tyre width for bicycles: 6.25 inches, or 159 mm!
This new fat tyre size allows you to run lower tyre pressures than ever before, increasing the tyre footprint on the ground, and providing more flotation over this world’s softest surfaces. You can actually drop the tyre pressure down to just 1 or 2 psi!
To keep the overall wheel diameter in check, Surly has reduced the rim size to 24″. When combined with the 6.2″ tyre, this matches the overall wheel diameter of a 26 x 5.1″ model found on the Surly Ice Cream Truck (more or less).
With the smaller rim size, Surly can use a standard-length front fork, which in turn keeps the head tube at a reasonable length and the handlebars at an ideal height.
Why Is This Bike Ideal For Soft Surfaces?
Other than the all-new 6.2” Surly Molenda tyres, Surly has made some important frame modifications to suit soft surfaces.
They’ve dropped the top tube as low as possible to minimise the standover height. This should give you enough top tube clearance to dab your foot into the sand and not injure yourself.
In addition, the tall bottom bracket height provides plenty of clearance for backcountry riding and monster trucking over rocks, roots and grasses.
An interesting feature is the small handhold between the nook of the seat tube and the top tube. This makes the Moonlander a bit easier to lift and manoeuvre.
The Surly Moonlander V2 Is A Mid-Tail Fat Bike
Surly has also extended the rear end of the Moonlander. The chainstays are now 562 mm long, which is over 100 mm longer than previously.
These extra-long chainstays make the bike super stable at speed and prevent your front wheel from lifting while riding up steep inclines.
But importantly, the long chainstay length helps to create space for the 6.2″ wide rear tyre AND the front sprocket – it can get especially cosy at the chainstay near the tyre.
The Front and Rear Hubs Are Identical
The Surly Moonlander employs two rear hubs, which are both 197 mm in width. This is a somewhat standard size in the fat bike world, for example, it’s found on the Surly Ice Cream Truck.
The advantage of using identical front and rear wheels is that they’re interchangeable! This would allow you to fit different tooth sprockets on each wheel and swap them depending on how mountainous it is.
Alternatively, if the freewheel of one hub stopped functioning, you could swap the wheels around. Or if you partially damaged one wheel you could move it to the front where it will experience less stress.
The Surly Moonlander Is A Pinion Fat Bike
I’m excited to finally see a Surly bike with a Pinion gearbox!
Pinion gearboxes are less susceptible to damage than derailleurs, they don’t require any tuning or adjustment, they don’t wear out, and you can change gears at any time. There is very little cleaning too – the only maintenance is the 10,000km oil change which takes no more than 15 minutes to complete.
The gearbox model that Surly has picked is the Pinion C1.9 XR. This is a 9-speed box with a 568% range – that’s even more gear range than the best 1X derailleur setups. You can expect the biggest gear to be around 5.7x larger than the smallest, suiting almost all-terrain.
There is a custom high-offset spider that mounts the front sprocket with the perfect chain line for the 197 mm rear hub. Combined with the custom Pinion fat crank arms for Surly, the q-factor (distance between the right and left crank arms) works out to be the same as other fat cranksets (~230mm).
What Are The Moonlander Gear Ratios?
There is a 34-tooth front and 34-tooth rear sprocket.
When we run the calculations, we find that the Surly Moonlander has a 16″ low gear, and a 93″ high gear – that’s 1.3 to 7.4 in metres development. This should be low enough for almost all backcountry riding.
What Frame Material is the Surly Moonlander?
Surly uses double-butted steel tubes for the front triangle and straight gauge tubes for the rear triangle. An electro-deposition coating is applied to the frame, which protects it from corrosion.
What Other Wheel and Tyre Sizes Will Fit The Surly Moonlander?
The Surly Moonlander will also fit 26 x 5.1”, 27.5 x 4.8”, and 29 x 3.0” tyres.
What Mounts Does The Surly Moonlander Offer?
You’ll find 4x cargo cage mounts on the fork, fender mounts, rear rack mounts, and bottle cage mounts on each side of the downtube.
What If You Don’t Want To Use Tubeless?
Surly have a new TPU inner tube in the matching 24 x 6.2” size that can be run down at low pressures (2-10psi). The tubes are US $49 a piece.
As the TPU tubes don’t stretch to fill the tyre, they apparently provide even better sidewall support and improve the tyre’s traction.
How Much Does The Moonlander Weigh?
The Surly Moonlander tips the scales at 21.1 kilograms (46.6 lb).
This is quite heavy for a bicycle but I can assure you this mass will be very easily concealed when the terrain is soft.
How Tall Should You Be To Ride A Moonlander?
The Moonlander comes in four sizes from small to extra-large, and the stack and reach measurements are typical of rigid fat bikes.
This should suit riders from 163 cm through 198 cm (5ft4 to 6ft6).
Can You Fit A Suspension Fork On The Surly Moonlander?
You cannot fit any current mountain bike suspension fork on the Moonlander due to the monstrous front tyre width.
How Much Does The Surly Moonlander Cost?
You can get a Surly Moonlander for US $4,199 (complete bike) or just the frameset for US $1,199 (not including the gearbox).
Read more about the Surly Moonlander at SurlyBikes.
