Otso Cycles Announces the Arctodus – The fattest of the fat(bike)

Here’s what some of you have been waiting for. A fat bike that can run the biggest tires on the widest rims. Basically the monster truck of fat bikes. It’s called the Arctodus and I think that I might be in bike love. I’ve always thought that steel, fat bikes are really photogenic. The smaller diameter of the steel tubes coupled with the huge expanse of black rubber makes for a great-looking bike. I ride a ton of non-groomed conditions in the winter, so this platform could be right up my alley. I can’t wait to throw my leg over one of these bad bears! The press release with all of the details and an explanation of all of the innovative features is below.

Otso Cycles Introduces Arctodus. A Steel fat bike that can clear the biggest fat tires available.

Minneapolis, Minn. (October 11, 2022)

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, mounts, and extra room for cargo, and can clear the biggest fat bike tires on the market. Arctodus is ready for afternoon exploration, polar expeditions, and everything in between.

There’s no need to wait for the trail groomer. Arctodus was made for fresh 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 and Tuning Chip hardware. Even the geometry is catered for exploration, with extra trail for optimal flotation and bottom bracket height that will ride above deeper snow. A medium Arctodus has a head tube angle of 68.5º, a seat tube angle of 74º, and a trail of 94mm. Whether you’re exploring local trails or a national forest, you can trust Arctodus to keep you riding.

Arctodus was built around a 26″ x 4.8″ tire for optimal handling and control on loose trails. The biggest 26” 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. 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 +/- 0.2º. 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. No matter the conditions, Arctodus has an answer.

Also found in all Otso bikes is suspension-corrected geometry. Arctodus can fit a suspension fork with up to 120mm of travel. A port near the bottom of the seat tube accepts cable housing for a dropper post. This frame is compatible with the Tuning Chip dropout singlespeed kit for cyclists who prefer to ride without gears. The head tube sizing and standard are compatible with Wolf Tooth GeoShift Angle Headsets, which change the head tube angle by +/- 1º or 2º, This allows for a head tube angle range from 66.5º to 70.5º to further customize the ride.

Arctodus is available in two colorways: Glacier Blue & Purple and Black & Silver. The base build starts at $2,590 with Shimano SLX and aluminum components, while the frameset starts at $1,390. All components and accessories are customizable via the Custom Bike Builder, including drivetrain, tires, anodized accent colors, grips, and more. Find Arctodus now on OtsoCycles.com and with bike shops that stock Otso Cycles.

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Just an old cat that rides bikes, herds pixels, ropes gnomes and sometimes writes stories. I love a good story.


  1. Sweet Bike. I have always been curious about those angle headsets. Do the aftermarket ones void the warranty in anyway? I would love to make my bike a little more slack.

    • Otso employee here. Adding a Wolf Tooth GeoShift Angle Headset in the correct specs to Arctodus will not void the warranty, nor will any other headset that matches the frame specs. Go forth and add slack!

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