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    Big adventures require a bike that can rise to the occasion. Arctodus is named after Arctodus simus, an Ice Age behemoth that was the largest bear to ever walk the Earth. Like its namesake, Arctodus the bike is versatile, strong, and ready to explore. It has adjustable geometry, a durable steel frame, a massive front triangle for a frame bag, lots of cargo mounts, and can clear the biggest fat bike tires on the market. Arctodus is ready for afternoon exploration, polar expeditions, and everything in between.


    Otso bikes are available to purchase here on our website or with our network of Otso dealers. Our Custom Bike Configurator allows you to select most component options on your bike, including drivetrain, wheelset, tires, handlebars, seatpost, anodized accent color option, and more. Arctodus is also available as a frameset if you already have parts ready to go at home. We’re happy to talk through options to help you build the Arctodus that is perfect for you and your riding style.

    Arctodus Custom Bike Configurator Arctodus Custom Bike Configurator
    $ 2,395.00

    Arctodus SLX Arctodus SLX
    $ 2,395.00

    Arctodus Frameset Arctodus Frameset
    $ 1,495.00

    Note: Images may not show actual build kit content. Pricing and specifications subject to change without notice. Comparable components may be substituted when necessary to fulfill bike shipments.

    Otso has a small (but growing!) network of bike shops that sell our bikes. Click the button to the right to see a map of all Otso dealers. If there is not one in your area, you can still build and order any of our bikes right here on our website. Give us a shout at with any questions.  


    Arctodus was built around a 26" x 4.8" tire for optimal handling and control on loose trails. It can fit the biggest fat bike tires in the world. The biggest fat tire on the market is 26" x 5.05" and Arctodus eats them like a snack with room to spare. Same as 27.5" x 4.5", which is the biggest 27.5" tire available. Arctodus is the only bike to clear tires this big with a 12-speed drivetrain without chain interference. We achieve this by using a 5mm offset with the rear wheel. When a bike is created for big rides with fresh snow, it needs to fit tires that were designed for the same reason. This is a bike that prays for snow and cuts its own trail.


    A key feature in all Otso bikes is adjustable geometry and the ability to adapt the bike for the ride ahead. The patented Tuning Chip rear dropout system can change wheelbase length by up to 20mm, raise or lower the bottom bracket height by up to 4mm, and change the head tube angle by +/- 0.5º. Use the rear position when the trails are loose and you need as much control as you can get. Use the front position when the snow is firm and the trails let you take turns with a little speed. This frame is also compatible with Wolf Tooth GeoShift 1º and 2º Angle Headsets, effectively unlocking five head tube angles from 66.5º to 70.5º. No matter the conditions, Arctodus has an answer.


    There's no need to wait for the trail groomer. Arctodus was made for foot trails, forest paths, and snow-covered frozen lakes. The bombproof steel frame can withstand the demands of an expedition. A large front triangle can fit a healthy full frame bag. The carbon fork has mounts on either side for cargo. A rear rack can be attached via mounts on the seat stays. Even the geometry is catered for exploration, with optimal stability in deep snow. Whether you're exploring local trails or a national forest, you can trust Arctodus to keep you riding.



    Arctodus has a 100mm bottom bracket. This is 20mm narrower than other fat bikes that have the same tire clearance. Ride with massive tires without compromising handling.


    All Otso frames feature suspension-corrected geometry. Arctodus is compatible with suspension forks that have up to 120mm of travel. A few options are available on the Custom Bike Builder.


    Arctodus geometry was designed for optimal riding on fresh trails. The 68.5º head tube angle paired with massive tires gives Arctodus more stability than other fat bikes.


    A dropper post is a game changer in deep snow and technical winter riding. Arctodus has ample seat tube depth for longer travel dropper posts and a routing port just above the bottom bracket.


    Arctodus SLX Custom Bike Configurator
    Frame Chromoly with Tuning Chip™️ dropout system Chromoly with Tuning Chip™️ dropout system
    Fork Lithic full carbon fork, 15mm thru axle Lithic full carbon fork, 15mm thru axle
    Headset Wolf Tooth Performance headset Wolf Tooth, Custom Options
    Rear derailleur Shimano SLX M7100, 12-speed Custom Options
    Front derailleur N/A N/A
    Shifter Shimano SLX M7100, 12-speed Custom Options
    Cassette Shimano SLX M7100, 10-51T, 12-speed Custom Options
    Brakes Magura MT4 Custom Options
    Cranks Race Face Aeffect, Wolf Tooth CAMO 32T Round Chainring: 170mm S | 170mm M | 175mm L | 175mm XL Custom Options
    Bottom bracket Race Face, BSA 100mm Race Face, BSA 100mm
    Handlebar Aluminum, 31.8mm x 780mm, 20mm rise Custom Options
    Grips Wolf Tooth Fat Paw Grips, black Wolf Tooth, Custom Options
    Stem Aluminum +/- 7, 60mm S | 70mm M | 80mm L | 90mm XL Custom Options
    Seatpost Aluminum, 31.6mm x 400mm Custom Options
    Seatpost clamp Wolf Tooth 34.9, black Wolf Tooth, Custom Options
    Saddle WTB Volt 142mm WTB Volt 142mm
    Wheels Lithic Cryolite 100, 26", 97mm inner width, 150x15 thru axle front, 197x12 thru axle rear Custom Options
    Tires Schwalbe Al Mighty 26x4.8 Custom Options
    Chain Shimano SLX 12-speed Custom Options
    Frame Sizes S, M, L, XL S, M, L, XL
    Weight (size M, tubeless) 34.4 lbs Varies
    Frame SizeSmallMediumLargeX-Large
    Recommended rider height4'9"-5'5"5'5"-5'9"5'9"-6'1"6'1"-6'7"
    Recommended rider inseam29"-32"31"-33"32"-35"34"-37"
    Effective top tube589mm610mm632mm657mm
    Nominal head tube angle68.5°68.5°68.5°68.5°
    Tuning Chip induced head/seat tube angle change±0.2°±0.2°±0.2°±0.2°
    Head tube length90mm90mm100mm120mm
    Nominal seat tube angle74°74°74°74°
    Seat tube length380mm420mm465mm510mm
    Bottom bracket drop80mm80mm80mm80mm
    Chainstay length440-460mm440-460mm440-460mm440-460mm
    Fork offset51mm51mm51mm51mm
    Rigid fork axle to crown length485mm485mm485mm485mm

    Approved fit (tire width <126mm):
    26x4.8" Schwalbe Al Mighty on Lithic Cryolite 100
    26x5.0" Terrene Johnny 5 on Lithic Cryolite 100

    *For wheel/tire combinations not listed above, the max tire width should not exceed 126mm if you are running 12-speed, and clearance to the frame should never be less than 6mm.
    **Tire width and runout can vary by a couple millimeters, and tubeless tires will stretch slightly over time. Wheel dish will also affect chain clearance. Our tests were performed with new tires at 10psi on wheels dished 5mm to the non-driveside.

    Compatible fenders

    PDW - Mud Shovel Front and Rear Fenders

    SKS - Fatboard Fender Set


    compatible racks

    Axiom - Fatliner Rear Rack

    Salsa - Alternator Rear Rack 190 / 197

    Topeak - Uni Super Tourist Fat Rear Rack

    Blackburn - Outpost Fat Rear Rack

    Surly - Rear Disc Rack Wide


    Frame Bag Dimensions

    (click on links to view PDF drawings)