2018 Brother Cycles Big Bro Base

	Small (16)	Medium (18)	Large (20)	xLarge (22)
Stack	598mm	605mm	616mm	630mm
Reach	392mm	410mm	427mm	437mm
Stack to Reach Ratio	1.53:1	1.48:1	1.44:1	1.44:1
Seat Tube Length, C-T	406mm	457mm	508mm	559mm
Top Tube Length, Effective/Horizontal HT Top	575mm	595mm	615mm	630mm
Top Tube Length, Actual C-C	556mm	571mm	590mm	607mm
Top Tube Slope	22.3deg	17.2deg	12.8deg	9deg
Head Tube Angle	69.5deg	70deg	70.5deg	70.5deg
Seat Tube Angle	73deg	73deg	73deg	73deg
Head Tube Length	95mm	100mm	110mm	125mm
Bottom Bracket Drop	60mm	60mm	60mm	60mm
Bottom Bracket Height	308.2mm	308.2mm	308.2mm	308.2mm
Chainstay Length	445mm	445mm	445mm	445mm
Chainstay Length Horizontal	440.9mm	440.9mm	440.9mm	440.9mm
Front-Center	644.9mm	659.8mm	674.7mm	690.7mm
Front-Center Horizontal	642.1mm	657.1mm	672.1mm	688.1mm
Wheelbase	1083mm	1098mm	1113mm	1129mm
Fork Offset/Rake	46mm	46mm	46mm	46mm
Fork Length (Axle-To-Crown)	483mm	483mm	483mm	483mm
Trail	88.6mm very high	85.1mm very high	81.6mm very high	81.6mm very high
Mechanical Trail	83mm	79.9mm	76.9mm	76.9mm
Wheel Flop	29.1mm	27.3mm	25.7mm	25.7mm
Standover Height	782mm	810mm	840mm	871mm
Tire to Pedal Spindle	106.7mm 170 mm cranks	121.6mm 170 mm cranks	136.5mm 170 mm cranks	152.5mm 170 mm cranks
Pedal Spindle to Ground Clearance	138.2mm 170 mm cranks	138.2mm 170 mm cranks	138.2mm 170 mm cranks	138.2mm 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://www.brothercycles.com/shop/bikes/big-bro-complete/

Geometry