Bike-on-Bike
Default Config
Default Config
Insights
Average stack and reach vs trend of all-road/gravel bikes
Design deviates from other sizes of Serk Titanium A21
Somewhat upright stack and reach vs trend of progressive gravel bikes
Design deviates from other sizes of Mondince FM316
Geometry
Stack | 619mm | 620mm +1mm |
Reach | 403mm | 422mm +19mm |
Stack to Reach Ratio | 1.54:1 | 1.47:1 |
Seat Tube Length, C-T | 560mm | — |
Seat Tube Length, C-TTT | — | 510mm |
Top Tube Length, Effective/Horizontal HT Top | 594mm | 600mm +6mm |
Top Tube Slope | 8.4deg | 11deg +2.6deg |
Head Tube Angle | 70deg | 70.5deg +0.5deg |
Seat Tube Angle | 73deg | 74deg +1deg |
Head Tube Length | 188mm | 176mm -12mm |
Bottom Bracket Drop | 73mm | 75mm +2mm |
Bottom Bracket Height | 266mm | 276mm +10mm |
Chainstay Length | 430mm | 425mm -5mm |
Chainstay Length Horizontal | 423.8mm | 418.3mm -5.5mm |
Front-Center | 654mm | 671mm +17mm |
Front-Center Horizontal | 649.2mm | 664.7mm +15.5mm |
Wheelbase | 1073mm | 1083mm +10mm |
Fork Offset/Rake | 45mm | 50mm +5mm |
Fork Length (Axle-To-Crown) | — | 400mm |
Trail | 75.5mm high | 71.3mm -4.2mm high |
Mechanical Trail | 70.9mm | 67.2mm -3.7mm |
Wheel Flop | 24.3mm | 22.4mm -1.9mm |
Tire to Pedal Spindle | 145mm 170 mm cranks | 150mm +5mm 170 mm cranks |
Pedal Spindle to Ground Clearance | 96mm 170 mm cranks | 106mm +10mm 170 mm cranks |
Build
Wheel Size | 650B/27.5 in 584 mm BSD | 700C/29 in 622 mm BSD |
Tire Width | 47mm | 40mm -7mm |
Tire Outer Diameter | 678mm | 702mm +24mm |
Bike Length with Tires | 1751mm | 1785mm +34mm |
| Suspension Type | Rigid, non-suspension corrected | Rigid, non-suspension corrected |
| Bar Type | Drop Bar | Drop Bar |
| Frame Material | Titanium | Carbon/Composite |
| Fork Material | Carbon/Composite | Carbon/Composite |
| Brake Type | Disc | Disc |
Meta
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| Source | https://www.serk.cc/a21/ | https://www.anglecycle.com/2026-new-aero-downtube-drawer-gravel-bike-frame-fm316.html |
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