Surly Big Fat Dummy Frameset

£1,800.00
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All-Terrain, Fat Tire Trail Bike

Big Fat Dummy is truly a hulking beast of a bike. Maximalist bikepackers, those looking to make bikepacking a family affair, and those that help maintain their local trails will appreciate the Big Fat Dummy hauling abilities.

At first glance, it might just seem like a beefed-up version of Big Dummy, but that’s actually not the case. Specifically designed around fat tires, it has a longer toptube and slacker headtube offering the most stable, stiff, and predictable ride possible while hauling a lot of cargo.

  • Single-piece frame increases stiffness and decreases torsional flex
  • Human cargo compliant with the use of Dummy Rail Collars
  • Three-pack mounts, double water bottle bosses on seattube, internal dropper post routing
  • Clearance for 26" x 5.25" tires or 29” x 3.0” tires
Frame Construction

4130 Chromoly, Natch tubing, double-butted main triangle, trumpet flaired tubes, TIG welded, ED coated

Fork Construction

4130 Chromoly, Natch tubing, double-butted tapered fork blades, TIG welded, ED coated

Rear Dropout Configuration

Vertical

Rear Hub Spacing

12 x 197mm (Surly axle included)

10 x 190mm with Surly 10/12 Adapter Washers (not included)

Front Hub Spacing

15 x 150mm (Surly axle included)

Rear Brake

Disc - 51mm I.S. (203mm max rotor)

Front Brake

Disc - 51mm I.S. (203mm max rotor)

Head Tube

Ø44mm

Steerer Tube

Ø28.6mm (1-1/8")

Crown Race

Ø30mm (1-1/8")

Stock Headset Upper (S.H.I.S.)

ZS44/28.6

Stock Headset Lower (S.H.I.S.)

EC44/30

Seat Collar

Ø33.1mm

Seatpost

Ø30.9mm

Front Derailleur (Clamp)

High direct mount top-pull (Ø34.9mm)

55mm offset adapter (included)

Max Chainring (CL)[3]

No frame limitations

Bottom Bracket

100mm threaded (1.37" x 24TPI)

Tire Clearance Frame [1]/[2]

26 x 5.25" 

29 x 3.0"

Tire Clearance Fork [1]

26 x 5.25" 

29 x 3.0"

Rigid Fork Spec

468 x 47mm

Max Suspension Fork Length [4]

511 x 51mm (Fatbike 100mm)

Bottle Mounts Frame

2 Three-Pack (S)

2 Standard + 2 Three-Pack (M - L)

Bottle Mounts Fork

2 Three-Pack

Rack Mounts Frame

Yes (Surly Dummy Rails)

Rack Mounts Fork

Yes (upper, lower, and mid-blade threaded)

Fender Mounts Frame

N/A

Fender Mounts Fork

N/A

Other Features

Kickstand plate

Internal dropper post routing compatible