by Abbishek V Bharadwaj October 29, 2025 1 min read
The Cosmic 27.5 FATSO 21-Speed is Cosmic’s rugged all-terrain fat bike built for riders seeking adventure, stability, and bold styling in one package. Designed for comfort on rough tracks, trails, and city rides alike, it pairs a durable steel frame with wide 3-inch tires and a reliable Shimano 21-speed drivetrain.
Cosmic promotes it as a “ride-anywhere” model equally comfortable on city roads, mud paths, or sandy stretches.
“Adventure meets control the FATSO is made to conquer any surface you dare to ride.”
The FATSO 27.5’s frame is constructed from Hi-Tensile steel, known for toughness and vibration damping on uneven terrain. Its trail geometry provides a slightly upright riding position, offering better balance and control. Reinforced welding around the head tube and bottom bracket enhances durability — crucial for off-road usage.
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Strong, stable, and built for the road less traveled
The bike features a Shimano Tourney 21-speed drivetrain (3×7 setup) controlled by Shimano EF500 shifters. The gear range, from the 14–28T freewheel paired with a triple crankset, offers flexibility for climbs and flats alike. The shifting action is smooth for its category, and the Tourney setup is reliable and easy to maintain.
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Shift confidently through any surface — the 21-speed drivetrain keeps you in control.
Comfort is where the FATSO shines. The combination of its steel frame and 27.5” × 3.0” fat tires offers excellent cushioning on gravel, trails, and even pothole-filled city roads. The upright geometry reduces strain on the back and shoulders, making long rides manageable.
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Fat tires deliver unmatched grip and comfort — gliding over sand, mud, or gravel
The FATSO comes equipped with dual mechanical disc brakes, delivering strong and predictable braking in both dry and wet conditions. While they may require occasional tuning, they perform better than rim brakes, especially off-road.
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Reliable disc brakes and wide handlebars keep you in command wherever you ride
The highlight feature — 27.5” × 3.0” oversized fat tires mounted on double-wall alloy rims — defines the FATSO’s identity. They provide superior grip, shock absorption, and stability across sand, grass, and rocky paths. The wide contact patch ensures traction even at lower pressures, making it a joy for leisure and off-road enthusiasts.
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Big tires, big control — the FATSO’s wheel setup lets you float over anything
The Cosmic 27.5 FATSO 21-Speed is a versatile fat bike offering adventure-ready stability, eye-catching design, and a reliable drivetrain at an affordable price. It’s best suited for riders who enjoy exploring multiple terrains — from rough paths to urban roads — without the need for complex maintenance.