Compare: 2023 BMC Switzerland Kaius 01 One 61 vs 2025 Serk Titanium A40 Base XXL

Insights

Somewhat upright stack and reach vs trend of progressive gravel bikes

Average stack and reach vs trend of all-road/gravel bikes

Design deviates from other sizes of Serk Titanium A40

Stack	620mm	638mm +18mm
Reach	414mm	406mm -8mm
Stack to Reach Ratio	1.5:1	1.57:1
Seat Tube Length, C-T	533mm	—
Seat Tube Length, Unknown	—	585mm
Top Tube Length, Effective/Horizontal Center	604mm	—
Top Tube Length, Effective/Horizontal Unknown	—	601mm
Top Tube Slope	11deg	7.8deg -3.2deg
Head Tube Angle	72deg	71.5deg -0.5deg
Seat Tube Angle	73deg	73deg +0deg
Head Tube Length	196mm	218mm +22mm
Bottom Bracket Drop	80mm	73mm -7mm
Bottom Bracket Height	271mm	278mm +7mm
Chainstay Length	—	420mm
Chainstay Length Horizontal	420mm	413.6mm -6.4mm
Front-Center	644mm	648.5mm +4.5mm
Front-Center Horizontal	631mm	644.4mm +13.4mm
Wheelbase	1051mm	1058mm +7mm
Fork Offset/Rake	45mm	47mm +2mm
Fork Length (Axle-To-Crown)	387mm	—
Trail	66.7mm high	67.9mm +1.2mm high
Mechanical Trail	63.5mm	64.4mm +0.9mm
Wheel Flop	19.6mm	20.4mm +0.8mm
Standover Height	818mm	855mm +37mm
Tire to Pedal Spindle	118mm 175 mm cranks	127.5mm +9.5mm 170 mm cranks
Pedal Spindle to Ground Clearance	96mm 175 mm cranks	108mm +12mm 170 mm cranks

Wheel Size	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD
Tire Width	40mm	40mm +0mm
Tire Width Max	44mm	—
Tire Outer Diameter	702mm	702mm +0mm
Bike Length with Tires	1753mm	1760mm +7mm
Crank Length	175mm	—
Stem Length	110mm	—
Stem Angle	-12.5deg	—
Suspension Type	Rigid, non-suspension corrected	Rigid, non-suspension corrected
Bar Type	Drop Bar	Drop Bar
Frame Material	Carbon/Composite	Titanium
Fork Material	Carbon/Composite	Carbon/Composite
Brake Type	Disc	Unknown