Tumbleweed’s New Fat-bike Looks VERY Interesting!

The folks at the Tumbleweed Bicycle Company have developed the Prospector with bikepacking in mind and have built in some unique features including what they bill as it being the first production fat-bike to use a standard 73mm bottom bracket.


The Prospector is designed to be rugged, adaptable, and to carry a load – Tumbleweed continues the adventure, even after the trail ends. The Prospector is the first production fat-bike to use a standard 73mm bottom bracket and can handle a variety of tire sizes and wheel combinations, up to a 4” tire. Utilizing common mountain bike parts and existing standards, allowing for easy and affordable part sourcing – a necessity when traveling in remote or international locations. Designed around the 14 speed Rohloff hub for maintenance free shifting, the Prospector is also front and rear derailleur compatible.


A custom bottom bracket yoke and 73mm Phil Wood EBB (Eccentric Bottom Bracket) allows for maximum tire and mud clearance while maintaining a narrow pedaling stance and allowing the use of many off-the-shelf mountain bike cranks. The EBB allows the rider to set BB height and tension the chain, all while keeping the rear wheel locked in the correct position.


With over a decade of researching, building, and riding various off road touring bikes in the harshest terrains worldwide, Tumbleweed breaks the mold on production bikepacking frames.


Tumbleweed Prospector Frame Specs:

  • Tumbleweed hollow cast BB yoke (Designed by Anna Schwinn) for maximum tire and mud clearance. Compatible with most Shimano mountain cranksets
  • 73mm Tumbleweed exclusive Phil Wood Eccentric Bottom Bracket.
  • Double butted, heat treated chromoly tubing.
  • Tumbleweed vertical dropouts (Designed by Anna Schwinn) with Rohloff OEM slot and chainstay mounted disc brake. M6 and M5 Rack and Fender mounts. Replaceable derailleur hanger (Wheels Manufacturing number 6)
  • Braze ons: Front and rear rack and fender mounts, three water bottle mounts on frame, triple water bottle mounts on fork
  • 135mm symmetrical QR rear hub spacing
  • 135mm fork spacing for rear disc spaced hubs, allows front and rear wheel interchangeability. Unicrown, 100mm suspension corrected
  • Tire clearance for 26×4″ on 65mm rim (Rohloff SPEEDHUB or singlespeed only), 29×3.0″ on 50mm rim, or 27.5×3.25″ on 50mm rim
  • Chainring clearance: 24-38 Mountain Double, or 24-32-42 Mountain Triple. Chainring clearance is only limited when the Eccentric BB is in the far rearward position. Larger chainring combinations may be used if this rear position is avoided. In order to use a 3″ tire with derailleurs, a 1x or offset 2x crankset must be used.
  • 31.6mm seatpost, 35mm seat clamp
  • Available Colors: New Mexico Turquoise and Desert Sandglow
  • MSRP: $1,450 (Frame)

We are working on getting one of these for a full test so stay tuned, meanwhile learn more about the Prospector at Tumbleweed Bicycle Company www.tumbleweed.cc