2019 Surly Bikes Big Fat Dummy Base

	SM	MD	LG
Stack	569mm	597mm	625mm
Reach	411mm	432mm	448mm
Stack to Reach Ratio	1.38:1	1.38:1	1.4:1
Seat Tube Length, C-T	356mm	432mm	508mm
Top Tube Length, Effective/Horizontal Center	590mm	620mm	645mm
Top Tube Slope	23.9deg	18.2deg	13.2deg
Head Tube Angle	69deg	69deg	69deg
Seat Tube Angle	72.5deg	72.5deg	72.5deg
Head Tube Length	90mm	120mm	150mm
Bottom Bracket Drop	55mm	55mm	55mm
Bottom Bracket Height	332.2mm	332.2mm	332.2mm
Chainstay Length	875mm	875mm	875mm
Chainstay Length Horizontal	873.3mm	873.3mm	873.3mm
Front-Center	661mm	691.9mm	718.8mm
Front-Center Horizontal	658.7mm	689.7mm	716.7mm
Wheelbase	1532mm	1563mm	1590mm
Fork Offset/Rake	47mm	47mm	47mm
Fork Length (Axle-To-Crown)	468mm	468mm	468mm
Trail	98.3mm very high	98.3mm very high	98.3mm very high
Mechanical Trail	91.8mm	91.8mm	91.8mm
Wheel Flop	32.9mm	32.9mm	32.9mm
Standover Height	740mm	790mm	840mm
Tire to Pedal Spindle	103.8mm 170 mm cranks	134.7mm 170 mm cranks	161.6mm 170 mm cranks
Pedal Spindle to Ground Clearance	162.2mm 170 mm cranks	162.2mm 170 mm cranks	162.2mm 170 mm cranks

Very Upright

Somewhat Upright

Average

Somewhat Aggressive

Very Aggressive

The Bike Insights Upright/Aggressive scale is based on analysis of a bike’s proportions relative to similar sized bikes in the same category.

Category Trend

Source:https://surlybikes.com/bikes/big_fat_dummy/bike_info

Geometry