Posted on October 5, 2022 by Zach Overholt
It’s now been six years since Otso Cycles spun out of Wolf Tooth Components, introducing the Voytek fat bike to the world in the process. In our opinion, that Voytek is still one of the best fat bikes you can buy, but it hasn’t stopped Otso from thinking about what comes next. From one legendary bear to another, the Arctodus gets its name from the Ice Age monster that was supposedly the largest bear to ever walk the earth.
That’s fitting since the Actodus fat bike is meant to roll the biggest fat bike tires currently available…
All photos c. Otso Cycles
Starting with a chromoly steel frame, it’s clear that the Arctodus is built for slightly different adventures than the carbon fiber Voytek. Designed specifically for maximum stability & flotation with backcountry-worthy durability, the Actodus is meant to stand alongside the Voytek – not replace it.
It’s no big surprise that the frame continues the use of Otso’s excellent Tuning Chip dropout system. Given the wide variety of tire and wheel sizes the Arctodus is built for, the ability to adjust the wheel base by 20mm, BB height by 4mm, and the head tube angle by +/-0.5º will be a welcomed touch.
Up front, the Arctodus is suspension corrected for a 120mm fork with a 68.5º head tube angle and 485mm axle to crown. Want it slacker or steeper? The head tube is designed to work with the Wolf Tooth GeoShift Angle Headsets which can change the head tube angle by +/- 1º or 2º, allowing for head tube angles from 66.5º to 70.5º.
The Arctodus will be sold in four frame sizes from small to extra large.
In terms of tire clearance, the Actodus was built around a 26 x 4.8″ tire for optimal handling. However, the frame and fork will swallow a 26 x 5.05″ or 27.5 x 4.5″ tire with ease. Actually, the frame will clear up to a 26 x 5.25″ tire and the fork will clear up to a 26 x 5.4″ tire on 100mm rims – though tires that wide don’t actually exist (yet?). It’s important to note that the Arctodus frame offers the same clearance in all Tuning Chip Positions, not just at the back.
Yes, there are other frames on the market that will clear tires that wide but Otso claims this is the only frame on the market that will allow for the use of a 12-speed drivetrain without any chain interference with the tire.
More impressive is that Otso was able to accomplish this while keeping the q-factor relatively narrow with a 100mm BSA bottom bracket. It’s not Voytek-narrow, but at 205mm with a RaceFace Aeffect crankset, it’s impressively compact considering the tire clearance, drivetrain clearance, and 36t round chainring clearance.
How did they do it? It all centers around a 197 x 12mm rear hub that is offset to the driveside by 5mm. That places the cassette farther out from the tire, and allows for the chain/tire clearance.
The Arctodus is dropper post compatible with a cable port in the seat tube, and runs full external housing for brakes and derailleurs. You’ll find three-pack mounts on the inside of the downtube, and on both fork lets, plus standard bottle cage mounts on the seat tube and the bottom of the downtube. There are also rear rack mounts for the frame.
Available now in Glacier Blue & Purple, or Black & Silver, complete base builds start at $2,590 with Shimano SLX 1×12 and the frameset will be offered for $1,390. As usual, the components are all customizable through the Otso Custom Bike Builder.
Zach Overholt is the Editor in Chief of Bikerumor. He has been writing about what’s new in the bicycle world for 12+ years. Prior to that, Zach spent many years in the back of a bicycle shop building and repairing nearly every type of bike, while figuring out how to (occasionally) ride them.
Based in Ohio, Zach is now slowly introducing a new generation to cycling and still trying to figure out how to fit the most rides into a busy schedule as a new dad.
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