Rare Earth Cycles Sisu Fat Bike

Brian Hall of Rare Earth Cycle Craft builds gorgeous bicycle frames in his River Falls, Wisconsin, shop. As an alumnus of Waterford Precision Cycles, I’ve followed this fellow frame builder since I first learned of him on The Radavist after he finished the Baja Divide. His Sisu fat bike alone is worthy of a post on Fat-Bike.com. As an avid bikepacker myself, I was also intrigued that Brian took that Horse With No Name frame across the Tour Divide Route after the Baja Divide. It was obvious that this guy had no fear!

But when he modified a factory Otso Actodus into a step-through frame to accommodate an 86-year-old ripper with some mobility issues to keep riding, I contacted him to ask if I could drive down for a shop visit. Brian was gracious and said he would be happy to show me his shop. He also mentioned he was just finishing up a special single-speed bike to be raced on the Tour Divide Route later this year. I grabbed my camera gear, hopped in my little Ford Maverick, and took off for River Falls.

Always a maker of some kind, Brian started building frames as a hobby in his garage during the pandemic. In 2022, he retired from a career in footwear design and development, sold the farm, and started riding the Baja Divide on a Horse With No Name frame he built specifically for the trip. John Watson at The Radavist did a nice piece on the bike if you want to check it out. Brian got back to Wisconsin in February of 2023, found a place to live with a good shop space, and Rare Earth Cycle Craft was born.

Back to fat bikes and Brian’s very cool Sisu model. Proud Finnish people are quick to say the word “Sisu” cannot be translated into other languages, but originated from the Finnish word ‘sisus’, which means ‘guts’ or ‘insides’. That is why it is often translated as inner strength, stoic determination, hardiness, courage, and resilience.

An apt name for a fat bike that was built with trail geometry, to be a year-round mountain bike with a narrower Q Factor than most fat bikes. Brian built the frame around an 83mm downhill bottom bracket, giving it a Q Factor of 188mm with the Appleman Cycles cranks and maximum 4” x 27.5 tire clearance. The frame is a mix of 4130 and Columbus Zona tubing, has Paragon Machine Works UDH dropouts with 177 rear/150 front axle spacing.

• Build kit:
• White Industries headset
• Enve M6 carbon riser bar
• Industry 9 stem
• Paul Love Levers
• Paul Klamper brakes
• Light Bicycle 27.5 carbon rims
• Berd spokes
• Onyx Vesper hook flange hubs
• Maxxis FBF and FBR 27.5×3.8” tires
• Appleman Cycles 165mm cranks and spider
• Alugear 32t chainring
• One Up V1 dropper post
• Ergon SMC saddle
• GX AXS Transmission shifter, derailleur, and cassette

In addition to the mix of elegantly curved tubing, the frame also has Brian’s signature double top tube and portage handle between the drive-side seat stay and seat tube. The front fork has a truss-style look, without the complications of a full-truss head tube construction like his Horse With No Name bikepacking frame.

I was particularly intrigued by the BerdSpoke/Onyx hooked hub. I don’t really care about the weight savings, but Berd pokes are supposed to be almost indestructible and reduce vibrations for an improved ride quality. And if you do break a spoke, the ability to replace it so easily in the field while bikepacking is very tempting. I also like the fact that the spokes and hubs are manufactured by my neighbors in Minnesota.

Brian used an off-the-shelf Enve handlebar and Industry Nine stem, but many of his frames get custom titanium handlebar/stem combos he bends and builds himself. Each Rare Earth frame built so far has had its own unique headbadge. While I was at Brian’s shop, I also photographed a stunning single-speed 29er Tour Divide Route race bike Brian built for Randy Windle (@windlecommarandy) from Arkansas. Brian was able to incorporate a small piece of Hachita, New Mexico turquoise from near the southern terminus of the Tour Divide.

I hope to make another trip to Rare Earth Cycle Craft in the near future to photograph Brian during the frame-building process to share more of his thoughtful craftsmanship. Stay tuned to your Fat-Bike.com channels for that one.

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Are you a frame builder making custom fat-bikes? Give us a shout! We’d love to learn about your craft and process. We will be making several trip in the next few months and if we pass through your area we’d love to visit! Get in touch at [email protected].