	390	440	480	530
Stack	600mm	605mm	619mm	628mm
Reach	419mm	444mm	464mm	491mm
Stack to Reach Ratio	1.43:1	1.36:1	1.33:1	1.28:1
Seat Tube Length, Effective Unknown	390mm	440mm	480mm	530mm
Top Tube Length, Effective/Horizontal Unknown	575mm	602mm	625mm	657mm
Head Tube Angle	67.9deg	67.9deg	67.9deg	67.9deg
Seat Tube Angle	75.4deg	75.4deg	75.3deg	75.3deg
Head Tube Length	90mm	95mm	110mm	120mm
Bottom Bracket Drop	60.6mm	61.2mm	61.4mm	61.8mm
Bottom Bracket Height	307.7mm	307.1mm	306.9mm	306.5mm
Chainstay Length	425mm	425mm	425mm	425mm
Chainstay Length Horizontal	420.7mm	420.6mm	420.5mm	420.5mm
Front-Center	694mm	731mm	746mm	771mm
Front-Center Horizontal	691.4mm	728.4mm	743.5mm	768.5mm
Wheelbase	1112mm	1149mm	1164mm	1189mm
Fork Offset/Rake	49.4mm	59mm	49.2mm	44.1mm
Trail	96.2mm very high	85.9mm very high	96.5mm very high	101.9mm very high
Mechanical Trail	89.2mm	79.6mm	89.4mm	94.5mm
Wheel Flop	33.5mm	30mm	33.6mm	35.5mm
Tire to Pedal Spindle	155.7mm 170 mm cranks	192.7mm 170 mm cranks	207.7mm 170 mm cranks	232.7mm 170 mm cranks
Pedal Spindle to Ground Clearance	137.7mm 170 mm cranks	137.1mm 170 mm cranks	136.9mm 170 mm cranks	136.5mm 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.

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2025 TanTan Cycling (Seraph) FM539 29"

Geometry