2023 Surly Bikes Big Dummy Base

	SM	MD	LG
Stack	571.1mm	599.3mm	627.4mm
Reach	409.9mm	431.1mm	447.2mm
Stack to Reach Ratio	1.39:1	1.39:1	1.4:1
Seat Tube Length, C-TTT	406mm	432mm	508mm
Top Tube Length, Effective/Horizontal HT Top	590mm	620mm	645mm
Top Tube Slope	17deg	16.5deg	11.6deg
Head Tube Angle	70deg	70deg	70deg
Seat Tube Angle	72.5deg	72.5deg	72.5deg
Head Tube Length	150mm	180mm	210mm
Bottom Bracket Drop	40mm	40mm	40mm
Bottom Bracket Height	303mm	303mm	303mm
Chainstay Length	821mm	821mm	821mm
Chainstay Length Horizontal	820mm	820mm	820mm
Front-Center	650.2mm	681.6mm	707.9mm
Front-Center Horizontal	649mm	680.4mm	706.8mm
Wheelbase	1469mm	1500.4mm	1526.8mm
Fork Offset/Rake	43mm	43mm	43mm
Fork Length (Axle-To-Crown)	417.8mm	417.8mm	417.8mm
Trail	79.1mm high	79.1mm high	79.1mm high
Mechanical Trail	74.3mm	74.3mm	74.3mm
Wheel Flop	25.4mm	25.4mm	25.4mm
Standover Height	725mm	773mm	823mm
Tire to Pedal Spindle	137.2mm 170 mm cranks	163.6mm 175 mm cranks	189.9mm 175 mm cranks
Pedal Spindle to Ground Clearance	133mm 170 mm cranks	128mm 175 mm cranks	128mm 175 mm cranks

Published Sizing Recommendations

Height

133 ft 4 in

148 ft 2 in

139 ft 8 in

152 ft 5 in

148 ft 2 in

163 ft 0 in

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_dummy#spec-geo