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    Fenrir Stainless


    The Otso Fenrir is a ride-anywhere bike for bikepacking races and afternoon adventures alike. It can be built with drop bars or with MTB bars and both selections are available as stock build options. A tire clearance of 29” x 2.8” or 27.5” x 3.0” keeps the Fenrir rolling on rough terrain, while extra frame and fork braze-ons are ready to carry gear for days or weeks on the trail. Like all Otso bikes, the Fenrir has adjustable geometry via the patented Tuning Chip rear dropout system that makes the bike as adaptable as its rider.


    While all Otso bikes are known for their versatility, the Fenrir might be the most versatile yet. It was designed to accommodate drop bars with a 50mm stem or MTB bars with an 80mm stem. It can be built with gears or single speed, with a suspension fork or rigid, with a mechanical or electronic drivetrain, or with a dropper or rigid seat post. The ability to fully customize the build of the bike makes the Fenrir as versatile as its rider.


    The Fenrir was designed with the option to be built with drop bars or MTB bars. When configured with drop bars, the Fenrir rides like an extra-capable gravel bike. The relatively longer top tube means a shorter stem is needed with drop bars to align with the rider's preferred reach. It can be built with standard road/CX/gravel bars for rides on local trails or with wider bars to fit a handlebar roll loaded with lots of gear.


    When built with MTB bars, Fenrir rides like a 90s XC bike. It's fun and lively, yet efficient and Capable with a capital C. It can handle any sketchy descent or technical climb with ease. Because the top tube is relatively short for a mountain bike, a longer stem (80-90mm) is ideal for maintaining reach. Ride it on your local singletrack or load 'er up for that backcountry tour that you've been dreaming about--you know the one. However you choose to build it, Fenrir will ride any road/trail on the map and carry all the gear to get you there.


    Every last feature of Fenrir is optimized for bikepacking. The stainless steel frame is strong, comfortable, and surprisingly light weight. It can be built with flat bars or drop bars depending on your affinity for large handlebar rolls. Single speed is an option for folks who like simplicity while touring. It has extra mounts on the frame and fork for hauling all the gear you'll need for days (or weeks) on the trail. The frame and fork can clear 29" x 2.8" or 27.5" x 3.0" tires for trails that are especially gnarly. No matter your destination and how long it takes to get there, Fenrir is ready.


    All metal Otso bikes have the option to be built single speed or with gears. Fenrir is included in that group because it has a small notch on the rear dropout near the Tuning Chip. If you build your Fenrir with gears, but want to convert to single speed later on, we have the single speed Tuning Chip available on our website alongside other accessories. There's no wrong way to build your Fenrir.




    A bikepacking bike needs to be able to carry all the gear for days or weeks on the trail. Fenrir has mounts for bottles, fenders, and racks. The Enve fork also has three-pack mounts on either side for sharing the load.


    Pick a trail on the map and ride it. Fenrir has the endurance of a gravel bike, with the stability of a mountain bike. Above all, it is Capable with a capital C so you can stay the course and reach your destination.


    A small port near the bottom of the seat tube allows for the cable routing of a dropper post. If you don't ride with a dropper, you probably won't even notice the port.


    Tires need to meet demands of the trail for traction, stability, and comfort. Fenrir can ride up to 29" x 2.8" or 27.5" x 3.0" tires.  


    Frame Custom butted austenitic stainless steel frame Custom butted austenitic stainless steel frame
    Fork Carbon Enve Mountain Fork, 15mm thru axle Carbon Enve Mountain Fork, 15mm thru axle
    Headset Wolf Tooth Performance Headset Wolf Tooth Performance Headset
    Rear derailleur Shimano GRX 810, 11-speed TRP G-Spec TR12, 12-speed
    Front derailleur N/A N/A
    Shifters Shimano GRX 600, 11-speed TRP G-Spec TR12, 12-speed
    Cassette Shimano SLX, 11-46T, 11-speed SRAM GX, 10-51T, 12-speed
    Brakes Shimano GRX 600 hydraulic Magura MT4 hydraulic
    Cranks Race Face Aeffect Race Face Aeffect
    Handlebar Lithic Corundum aluminum compact drop with 16° flare Lithic flat bar
    Tape / Grips Wolf Tooth Supple Lite Bar Tape Wolf Tooth silicone foam grips
    Wheels Sun Ringle Duroc 30 Sun Ringle Duroc 30
    Tires Maxxis Aspen 29" x 2.4" Maxxis Aspen 29" x 2.4"
    Frame Sizes XS, S, M, L, XL XS, S, M, L, XL
    Bottom bracket standard Shimano english thread BSA, Ø73mm
    Maximum chainring size 1x: 40T round or 38T oval
    Front derailleur type N/A
    Headset ZS44/28.6 upper, EC44/40.0 lower
    Seatpost diameter Ø31.6mm
    Internal dropper post routing Yes. Exit port on bottom of seat tube
    Seatpost clamp Ø34.9mm
    Front/rear hub standard 110x15mm thru axle / 148x12mm thru axle
    Front/rear axle Ø15x100mm front, TP=1.5, TL=15mm / Ø12x187mm rear, TP=1.5, TL=12mm
    Derailleur hanger Wolf Tooth Tuning Chip Right Dropout
    Rear brake (rotor) Flat mount, 74mm post mount available(160mm)
    Front brake (rotor) Post mount native,(160mm post mount or 180mm flat mount)
    Fork axle-to-crown 490mm (suspension corrected for 100mm suspension fork)
    Fork offset 44mm or 52mm
    Bare frame weight (L) 5.7lbs (2580g)
    Fork weight (Enve rigid fork) 676g
    Tire clearance (frame) 2.3" at 420mm chainstay position, 2.6" at 430mm, 27.5" x 3.0" or 29" x 2.8" at 440mm
    Tire clearance (fork) Max clearance 29" x 2.8" or 27.5" x 3.0"
    Braze-ons 3 bottle mounts, fender, rack, cable clamps
    Frame Bag Dimensions X-Small Small Medium Large X-Large
    XS S M L XL
    Recommended rider height 4'10"-5'4" 5'3"-5'7" 5'7"-5'11" 5'11"-6'3" 6'3"-6'6"
    Effective top tube 547mm 565mm 583mm 600mm 618m
    Nominal head tube angle 68° 68° 68° 68° 68°
    Tuning Chip induced head/seat tube angle change ±0.2° ±0.2° ±0.2° ±0.2° ±0.2°
    Head tube length 90mm 100mm 120m 140mm 160mm
    Nominal seat tube angle 75° 75° 75° 75° 75°
    Seat tube length 360mm 400mm 450mm 490mm 530mm
    Bottom bracket drop 68-72mm 68-72mm 68-72mm 68-72mm 68-72mm
    Chainstay length 430-450mm 430-450mm 430-450mm 430-450mm 430-450mm
    Wheelbase 1090-1110mm 1110-1120mm 1130-1150mm 1150-1170mm 1170-1190mm
    Trail 88mm 88mm 88mm 88mm 88mm
    Fork offset 51mm 51mm 51mm 51mm 51mm
    Rigid fork axle to crown length 495mm 495mm 495mm 495mm 495mm
    Stack 595mm 605mm 623mm 642mm 660mm
    Reach 387mm 403mm 416mm 428mm 441mm
    Standover 754mm 777mm 810mm 838mm 866mm

    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.

    Fenrir Stainless Flat Bar
    $ 4,120.00

    Fenrir Stainless Frameset
    $ 2,050.00

    Fenrir Stainless Drop Bar
    $ 4,120.00

    Fenrir Ti Frameset
    $ 3,550.00

    Fenrir Ti Drop Bar
    $ 5,120.00

    Fenrir Ti Flat Bar
    $ 5,120.00