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Moonlander runs 4.8˝ tires on 100mm rims. Such a large footprint allows you to ride them at very low pressure, which (as with a snowshoe) enables unparalleled traction and float over all kinds of terrain…wet stuff, roots, rocks, pebbles, gravel, sand, and many types of snow. Moonlander, like its name implies, is meant to go beyond where normal bikes, even normal fat bikes, can go. It is designed from the ground up to ride where there are no roads, no trails and no people.

Like all of our framesets, Moonlander is made of 4130 CroMoly steel, with tubing designed specifically for this frame. The frame’s geometry is not unlike a standard mountain bike, with a bottom bracket height that supplies plenty of clearance for bushwhacking and monster-trucking while remaining low enough for a stable ride. The toptube maximizes standover height while keeping the headtube fairly high so you can set up your rig with a comfortable, all-day-grind riding position.

The frame features 135mm-spaced horizontal ‘dropouts’ with a derailleur hanger, meaning you can set it up as a singlespeed, with an internal gear hub, or standard derailleur drivetrain. The rear end is offset 28mm to allow the drivetrain and wide tires to play nicely together. Moonlanders come with a 135mm O.L.D. non-offset fork, but if you like being able to swap front and rear wheels you could get one matching the rear offset. The fork sports a 51mm I.S. disc caliper mount designed for a rear brake, and mid-blade thru-eyelets and lower rack barrels for mounting a fender and rack (you’ll probably need to alter something to fit, but the option is there should you choose to).


Moonlander Geometry 2014
SIZE Small (16) Medium (18) Large (20) xLarge (22) xxLarge (22L)
Reach 15.7 397.7 16.3 414.8 16.9 429.0 17.3 438.3 17.7 448.9
Stack 22.8 580.1 23.2 589.5 23.9 608.3 24.7 627.2 25.2 641.3
Head Tube Angle 70.5° 70.5° 70.5° 70.5° 70.5°
Head Tube Length 4.3 110.0 4.7 120.0 5.5 140.0 6.3 160.0 6.9 175.0
Seat Tube Length 16.0 406.4 18.0 457.2 20.0 508.0 22.0 558.8 22.0 558.8
BB Drop 2.4 60.0 2.4 60.0 2.4 60.0 2.4 60.0 2.4 60.0
Wheelbase 42.3 1073.4 43.1 1093.9 43.9 1114.8 44.5 1130.7 45.1 1146.4
Chainstay Length 17.7 450.0 17.7 450.0 17.7 450.0 17.7 450.0 17.7 450.0
Top Tube Length, Actual 21.9 555.2 22.5 570.8 23.2 590.2 23.9 607.3 24.4 620.6
Top Tube Length, Effective 22.6 575.0 23.4 595.5 24.2 615.0 24.8 630.0 25.4 645.0
Seat Tube Angle 73.0° 73.0° 73.0° 73.0° 73.0°
Standover Height 30.4 771.1 31.5 800.1 32.8 833.8 34.2 868.0 34.4 875.0
Fork Length 17.6 447.0 17.6 447.0 17.6 447.0 17.6 447.0 17.6 447.0
Fork Rake 1.7 43.0 1.7 43.0 1.7 43.0 1.7 43.0 1.7 43.0

All dimensions are preliminary and subject to change * Standover is measured from the top of the TT, at the center, with a tire measuring approximately Ø762mm


Surly 4130 CroMoly steel. Main triangle double-butted. TIG-welded. ED coated.

Rear Dropouts

Surly horizontal rear load, with derailleur hanger; 135mm O.L.D.; offset 28.0mm

Brake Compatibility

51mm IS disc mounts frame and fork. NOTE: Unlike Pugsley, Moonlander uses front caliper adapters for the front brake and rear caliper adapters for the rear brake.


Dual water bottle mounts, Surly Trip Guide full line guides for brake and derailleurs, fender and rack eyelets

Seatpost Diameter


Seatpost Clamp Diameter

30.0mm (Surly stainless included)

Headset/Steerer Tube

1-1/8" threadless

Front Derailleur Clamp Diameter

Direct mount 28.6mm diameter (adapter included, Moonlander specific)

Bottom Bracket Shell

100mm wide, standard English threading (1.37" x 24t)

Chainring Clearance

22/36t (NOTE: this is specific to using a Surly offset double crank—use of other cranks may limit number and size of rings and may cause tire/chain rub!)

Tire Clearance

4.8" tires on 100mm rims, hell yes.


Tapered straight blade butted 4130 CroMoly. 51mm IS front disc mount. 135mm-spaced dropouts


Titanium Sand


Frame Warranty


This Surly product is warranted against defects in materials and workmanship for three years from the date of retail purchase of the product, subject to the limitations detailed below. Save your dated receipt for proof of purchase.

This warranty does NOT cover the following:

  • Damage due to improper assembly or follow-up maintenance or lack of skill, competence or experience of the user or assembler
  • Products that have been modified, neglected, used in competition or for commercial purposes, misused or abused, involved in accidents or anything other than normal use
  • Installation of components, parts or accessories not originally intended for or compatible with bicycle as sold
  • Damage or deterioration to the paint, surface finish, aesthetics or appearance of the product
  • Normal wear and tear
  • Labor required to remove and/or refit and re-adjust the product within the bicycle assembly

This limited warranty is expressly limited to the repair or replacement of a defective product, at the option of Surly, and is the sole remedy of the warranty. This limited warranty applies only to the original purchaser of the Surly product and is not transferrable. This warranty applies only to products purchased through an authorized dealer or distributor. In no event shall Surly be liable for any loss, inconvenience or damage, whether direct, incidental, consequential, or otherwise resulting from breach of any express or implied warranty or condition, of merchantability, fitness for a particular purpose, or otherwise with respect to our products except as set forth herein.

This limited warranty gives the consumer specific legal rights, and those rights and other rights may vary from place to place. This limited warranty does not affect your statutory rights.