Fatboy 20
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Fatboy 20

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Fatboy 20
Technical Specifications

So Junior wants to get rad just like Mom and Dad? Well, our Fatboy 20 has your kid's name all over it. It has all the same benefits as our 'big kid' Fatboy, only it's built on 20-inch wheels for an ultra-low standover height and kids' size. The family that eats trails together stays together.

  • The frame features an A1 Premium Aluminum construction that provides the ideal blend of efficiency and durability, while the geometry creates a roomy top tube and short chainstays for easy climbing and confident descending.
  • Our A1 Premium Aluminum fork is lightweight and pairs up perfectly with the fat wheel system to soak up trail chatter and bumps.
  • The SRAM X4 9-speed rear derailleur provides plenty of gears for your little ones to make it up and down almost anything, while being tough enough for abuse.

Technical Specifications

CHAIN KMC X9, 9-speed w/ reusable MissingLink™
BOTTOM BRACKET Square taper, 100x151.5mm, sealed bearings
CRANKSET 9-speed, 28T chainring w/ chainguard
SHIFT LEVERS SRAM, trigger, 9-speed
CASSETTE Sunrace, 9-Speed, 11-36t
REAR DERAILLEUR SRAM X4, long cage, 6-/7-/8-speed
FRONT HUB Stout 135, loose ball bearings, 10x135 QR, 32h
REAR HUB Stout 170, loose ball bearings, 9-/10-speed cassette body, 10x170mm QR, 32h
INNER TUBES 20x4.0" tube, Presta valve
SPOKES Stainless, 14g
RIMS 20" disc, alloy construction, 68mm internal width, 32h
FRONT TIRE Ground Control Fat, 60 TPI, wire bead, 20x4.0"
REAR TIRE Ground Control Fat, 60 TPI, wire bead, 20x4.0"
SADDLE Specialized Youth, steel rails
SEATPOST Alloy, single-bolt, 27.2mm
STEM Alloy, 7-degree rise, 31.8mm clamp
HANDLEBARS Specialized, alloy, 9-degree backsweep, 4-degree upsweep, 680mm width, 31.8mm
GRIPS Specialized Body Geometry XCT, lock-on
FRONT BRAKE Tektro Aries, mechanical disc, organic pads, 160mm rotor 
REAR BRAKE Tektro Aries, mechanical disc, organic pads, 160mm rotor 
PEDALS Platform
SEAT BINDER Alloy, 31.8mm
FORK Specialized A1 Premium Aluminum, 1-1/8" alloy steerer
FRAME Fully butted Specialized A1 Premium Aluminum, ZeroStack head tube, 100mm-wide threaded bottom bracket, 170mm rear hub spacing


Geometry Chart

Fatboy - Geometry

Reach 319mm
Top Tube Length, Horizontal 470mm
Stack 464mm
Wheelbase 914mm
Chainstay Length 390mm
Front Center 526mm
BB Drop 25mm
BB Height 264mm
Seat Tube Angle 72°
Head Tube Angle 69°
Seat Tube Length 280mm
Head Tube Length 120mm
Bike Standover Height 583mm
Fork Rake/Offset 35mm
Fork Length, Full 360mm
Trail 75mm