Specialized Fatboy 20

Name: Specialized Fatboy 20
Brand: Specialized

2020 MountainFat bike Manufacturer page

Last known price: $770

Prices shown first for United States
Suspension: Rigid
Wheels: 20″
Drivetrain: 1 × 9 32t / 11–36t
Gear range: 327%
Frame: Aluminum
Brakes: Mechanical disc

Sizes

Size guide

The manufacturer did not publish rider heights for these sizes.

Components

12 of 22 identified

Parts found in a manufacturer catalog show their brand, model and key numbers, and the steps show how precisely they are identified: brand, series, model, or the exact product. The info button has every detail and the text the manufacturer published.

Frame and fork

1 part

Frame

Specialized A1 Premium Aluminum, fully-butted w/ smooth welds, ZeroStack head tube, 170mm rear hub spacing, replaceable alloy derailleur hanger Not identified

Suspension

1 part

Fork
- Specialized

Drivetrain

6 parts

Bottom bracket

Square taper, sealed cartridge bearings, 100mm shell, 164mm axle Not identified
Cassette
- SunRace 11–36t
Chain
- KMC X9 9 speeds
Crankset

Forged alloy, 32T, w/ chainguard, Alloy, 28T Not identified
Rear derailleur
- SRAM X4 7 speeds
Shifters
- SRAM X4

Brakes

2 parts

Brake levers
- Tektro
Brakes
- Tektro

Wheels and tires

5 parts

Front hub

Stout 135, loose ball bearings, 10x135 QR, 32h Not identified
Rear hub
- Specialized
Rims

24" disc, alloy construction, 68mm internal width, 32h Not identified
Spokes

Stainless, 14g Not identified
Tires

Front: Ground Control Fat, 60 TPI, wire bead, 20x4.0", Rear: Ground Control Fat, 60 TPI, wire bead, 20x4.0" Not identified

Cockpit and contact points

7 parts

Grips
- Specialized
Handlebar
- Specialized
Headset

1-1/8", threadless, ZeroStack, semi-cartridge bearings Not identified
Pedals

Platform Not identified
Saddle
- Specialized
Seatpost

Alloy, single bolt, 27.2mm Not identified
Stem
- Specialized

Sizes and geometry

1 size Open in the geometry plotter

Complete rider-height ranges are not published for these sizes. You can still explore the geometry below.

Size 11"

Table

Geometry diagram unavailable

The drawing needs wheelbase, reach, stack, head tube angle, seat tube angle, head tube length, seat tube length, chainstay length and bottom bracket drop / Bottom bracket height, which the manufacturer did not publish. Available facts remain in the table.

Size

Complete manufacturer geometry table 1 published size

Complete manufacturer geometry by size
Measurement
Crank lengthmm	127
Handlebar widthmm	640
Stem lengthmm	60
Seatpost lengthmm	300

Not published by the manufacturer: Reach, Stack, Top tube length, Seat tube length, Head tube length, Head tube angle, Seat tube angle, Chainstay length, Wheelbase, Front center, Bottom bracket drop, Bottom bracket height, Standover height, Fork rake, Trail, Stack/reach ratio, Front travel, Rear travel, Stem angle and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Aluminum
Fork material: Aluminum

Suspension

Suspension configuration: Rigid

Drivetrain

Derived by Bikelake

Front chainrings: 1
Smallest chainring: 32
Largest chainring: 32
Rear sprockets: 9
Smallest sprocket: 11
Largest sprocket: 36
Lowest gear: 17.8 in
Highest gear: 58.2 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Mechanical disc

Fit and controls

Seatpost: Rigid seatpost
Shifting: Mechanical

Additional specifications

Tire width: 4″
Travel: Front: Additional specification: Not available: Yes
Rear: Additional specification: Not available: Yes
Wheel material: Aluminum
Wheel size: 20″

Technical analysis

2 measures

How these figures sit among bicycles of the same class and model year. Context, not a ranking.

Lowest gear

17.8 gear inches

This value is within the central range for this class.

Cohort: Mountain / Fat bike Model year: 2020
Sample: 74 bicycles with this information
Coverage: 77.8% of the class

Highest gear

58.2 gear inches

This value is below the central range for this class.

Cohort: Mountain / Fat bike Model year: 2020
Sample: 74 bicycles with this information
Coverage: 77.8% of the class

Gearing

Estimated speeds at 80 rpm

Lowest gear: 6.8 km/h
Highest gear: 22.3 km/h

Total gear range 327%

Technical details and class reference

These speeds describe the gearing at the selected cadence, not how fast you can ride.
Calculated from published gear-inch values and their wheel-size assumptions.
These gearing values describe the bicycle, not a selected frame size.
A 100% range means one ratio; 500% means the highest ratio is five times the lowest.
For e-bikes, motor assistance cutoff is not represented.

Gear-inch range

Lower gear-inch values travel less distance per pedal revolution; higher values travel farther.

This bicycle: 17.8–58.2 gear inches
Class reference (p10–p90): 15.6–89.8 gear inches; The band runs from p10 for the lowest gear to p90 for the highest gear.

Cohort: Mountain / Fat bike Model year: 2020
Lowest gear: 74 bicycles with this information, 77.8% of the class
Highest gear: 74 bicycles with this information, 77.8% of the class

Lineup changes

The published facts that differ across this family's builds and from the same model a year earlier. Missing information never counts as zero.

Differences across 2020 builds
Specification	This bicycle Specialized Fatboy 20	Specialized Fatboy	Specialized Fatboy 24	Specialized Fatboy Comp Carbon	Specialized Fatboy SE
Frame
Frame material	Aluminum	Aluminum	Aluminum	Carbon	Aluminum
Fork material	Aluminum	Carbon	Aluminum	Carbon	Aluminum
Drivetrain
Smallest chainring	32	30	32	30	28
Largest chainring	32	30	32	30	28
Rear sprockets	9	12	9	12	10
Smallest sprocket	11	Not informed	11	10	11
Largest sprocket	36	Not informed	36	50	42
Lowest gear	17.8 in	Not informed	21.3 in	16.5 in	17.3 in
Highest gear	58.2 in	Not informed	69.8 in	82.5 in	66.2 in
Brakes
Brake type	Mechanical disc	Hydraulic disc	Mechanical disc	Hydraulic disc	Mechanical disc
Other specifications
Tire width	4″	3.8″	4″	3.8″	4.6″
Wheel size	20″	27.5″	24″	27.5″	26″
Bottom bracket standard	Not informed	Not informed	Not informed	PF30	BSA