Surly Big Dummy

Name: Surly Big Dummy
Brand: Surly

2025 UrbanUtilityLong-tail cargo Manufacturer page

Last known price: $2,449

Prices shown first for United States
Suspension: Rigid
Wheels: 26″
Drivetrain: 1 × 9 32t / 11–46t
Gear range: 418%
Frame: Steel
Brakes: Mechanical disc

Rider height by size (cm)

Size guide

SM 160–177.8
MD 167.6–182.9
LG 177.8–195.6

Components

15 of 20 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

100% Surly Chromoly steel, Natch tubing, double-butted main triangle, TIG welded Not identified

Suspension

1 part

Fork
- Surly

Drivetrain

7 parts

Bottom bracket

73mm BSA threaded (1.37" x 24TPI) Not identified
Cassette
- microSHIFT ADVENT H-Series 9 Speed Cassette 11-46 9 speeds 11–46t
Chain
- KMC X10 10 speeds
Crankset
- Race Face 32t
Front derailleur

None
Rear derailleur
- microSHIFT ADVENT Medium Cage Clutch 9 speeds
RD-M6195M
Shifters
- microSHIFT ADVENT Trail Trigger Shifter 1×9 9 speeds
SL-M9195

Brakes

3 parts

Brake levers
- SRAM FR-5
FR-5
Brakes
- Avid
Disc rotors

51mm IS (160-203mm) Not identified

Wheels and tires

4 parts

Front hub
- Novatec
Rear hub
- Novatec
Rims

OE, 38mm, 36h Not identified
Tires
- Surly

Cockpit and contact points

5 parts

Sizes and geometry

3 sizes Open in the geometry plotter

Enter your height to highlight matching ranges.

Size MD

Table

Reach 431mm

Stack 599mm

Wheelbase 1500mm

Head angle 70.0°

Seat angle 72.5°

Every size is drawn to the same scale, in millimeters. Explanatory schematic on an assumed 26″ wheel; exact published values are in the table below.

Size Reported by the manufacturer

Complete manufacturer geometry table 3 published sizes

Complete manufacturer geometry by size
Measurement
Frame
Reachmm	409.9	431.1	447.2
Stackmm	571.1	599.3	627.4
Top tube lengthmm	590	620	645
Seat tube lengthmm	406	432	508
Head tube lengthmm	150	180	210
Head tube angle	70°	70°	70°
Seat tube angle	72.5°	72.5°	72.5°
Chainstay lengthmm	821	821	821
Wheelbasemm	1469	1500.4	1526.8
Front centermm	650	682	708
Bottom bracket dropmm	40	40	40
Standover heightmm	725	773	823
Fork rakemm	43	43	43
Trailmm	70	70	70
Stack/reach ratio	1.39	1.39	1.40
Suspension and parts
Crank lengthmm	170	175	175
Handlebar widthmm	718	735	735
Stem lengthmm	70	70	80

Not published by the manufacturer: Bottom bracket height, Front travel, Rear travel, Stem angle, Seatpost length and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Steel
Fork material: Steel

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: 46
Lowest gear: 18.1 in
Highest gear: 75.6 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Mechanical disc

Fit and controls

Seatpost: Rigid seatpost
Shifting: Mechanical

Additional specifications

Bottom bracket standard: BSA
Tire width: 2.5″
Wheel material: Aluminum
Wheel size: 26″

Gearing

Estimated speeds at 80 rpm

Lowest gear: 6.9 km/h
Highest gear: 29.0 km/h

Total gear range 418%

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.