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Technical Specifications
All the fun of a fat bike with the performance of a Specialized. The Fatboy combines a lightweight frame and fork with 4.6" Ground Control tires to create a geometry similar to Specialized 29er geometry for nimble handling in the most extreme conditions.
  • Fat 26" disc, alloy single wall rims are designed to handle even the worst terrain
  • Specialized Ground Control Fat 26x4.6" tires roll over anything
  • Specialized FACT carbon fork w/ 5-inch tire clearance for stiff handling
  • Custom 2x10, forged alloy crankarm, w/ 100mm spindle for put the power down
  • Tektro Gemini, hydraulic disc brakes for reliable stopping power
  • SRAM X7, 10-speed, medium carbon cage derailleur for crisp and precise shifting
  • Fully butted M4 Premium Aluminum frame w/ up to 5-inch tire clearance is lightweight and stiff

Technical Specifications

CHAIN KMC X10L, 10-speed, reusable Missing Link
CRANKSET Custom Samox, 2x10, alloy, 100mm CNC spindle, w/ BB, 104/64mm BCD spider
FRONT DERAILLEUR SRAM X7, 2x10, low direct mount
SHIFT LEVERS SRAM S-Series, Grip Shift, 10-speed
CASSETTE Sunrace, 10-speed, 11-36
REAR DERAILLEUR SRAM X7 Type 2, 10-speed, medium cage
FORK Specialized FACT carbon, full monocoque, tapered steerer, 135mm hub spacing
FRONT HUB Specialized MTB Hi Lo disc, alloy, sealed cartridge bearings, 135mm wide, QR, 32h
INNER TUBES Standard, presta valve
SPOKES Stainless, 14g
RIMS Specialized Fatboy SL, alloy disc, single wall, 90mm wide, sleeve joint, hookless design, 32h
FRONT TIRE Specialized Ground Control Fat, 120TPI, folding bead, 26x4.6""
REAR TIRE Specialized Ground Control Fat, 120TPI, folding bead, 26x4.6""
SADDLE Body Geometry mountain, steel rails, 143mm
SEATPOST Alloy, 2-bolt, 12.5mm offset, 30.9mm, anti-corrosion hardware
STEM Specialized, 3D forged alloy, 4-bolt, 6-degree rise, anti-corrosion hardware
HANDLEBARS Specialized, low rise, double butted 6061 alloy, 9-degree backsweep, 5-degree upsweep, 15mm rise, 31.8mm
GRIPS SRAM, S-Series Grip Shift, 92mm
FRONT BRAKE Tektro Gemini, hydraulic disc, resin pads
BRAKE LEVERS Tektro Gemini, hydraulic
REAR BRAKE Tektro Gemini, hydraulic disc, resin pads
PEDALS Resin test ride, w/ toe clips, CEN std.
HEADSET 1-1/8"" upper, 1-1/2"" lower, Campy style, integrated sealed cartridge bearings, split crown race, 3.8mm cone spacer
SEAT BINDER Alloy, 34.9mm
FRAME Specialized M4 Premium Aluminum, fully butted w/ smooth welds, tapered headtube, post-mount disc dropouts, 190mm rear hub spacing, replaceable alloy derailleur hanger


Geometry Chart

Fatboy - Geometry

  S M L XL
Crank Length 170mm 175mm 175mm 175mm
Stem Length 60mm 60mm 70mm 70mm
Handle-Bar Width 750mm 750mm 750mm 750mm
Seat Tube Angle (Effective) 73° 73° 73° 73°
Reach 395mm 420mm 437mm 458mm
Stack 590mm 600mm 615mm 629mm
Bottom Bracket Drop 60mm 60mm 60mm 60mm
Chainstay Length 455mm 455mm 455mm 455mm
Head Tube Angle 70.5° 70.5° 70.5° 70.5°
Head Tube Length 110mm 120mm 135mm 150mm
Top Tube Length (Horizontal) 576mm 603mm 625mm 650mm
Seat Tube Length, Center to Top 394mm 445mm 483mm 533mm
Standover Height 757mm 793mm 820mm 849mm
Wheel Base 1083mm 1105mm 1128mm 1154mm
Seat Tube Angle (Actual) 73° 73° 73° 73°
Bottom Bracket Height 315mm 315mm 315mm 315mm
Seat-Post Length 350mm 350mm 400mm 400mm