Bike-on-Bike
Default Config
S
No Diagram
Default Config
Insights
Somewhat upright 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 LightCarbon LCG072-D
Geometry
Stack | 548mm | 547.3mm -0.7mm |
Reach | 364mm | 368mm +4mm |
Stack to Reach Ratio | 1.51:1 | 1.49:1 |
Seat Tube Length, C-T | 485mm | — |
Seat Tube Length, Effective Unknown | — | 480mm |
Top Tube Length, Effective/Horizontal Center | — | 525mm |
Top Tube Length, Effective/Horizontal HT Top | 523mm | — |
Top Tube Slope | 9.3deg | — |
Head Tube Angle | 70deg | 70.5deg +0.5deg |
Seat Tube Angle | 74deg | 74deg +0deg |
Head Tube Length | 110mm | 132mm +22mm |
Bottom Bracket Drop | 75mm | 79mm +4mm |
Bottom Bracket Height | 264mm | 282mm +18mm |
Chainstay Length | 430mm | 420mm -10mm |
Chainstay Length Horizontal | 423.4mm | 412.5mm -10.9mm |
Front-Center | 589mm | 593.7mm +4.7mm |
Front-Center Horizontal | 584.6mm | 591.5mm +6.9mm |
Wheelbase | 1008mm | 1004mm -4mm |
Fork Offset/Rake | 45mm | 51.5mm +6.5mm |
Fork Length (On-Axis) | — | 383mm |
Trail | 75.5mm high | 73.2mm -2.3mm high |
Mechanical Trail | 70.9mm | 69mm -1.9mm |
Wheel Flop | 24.3mm | 23mm -1.3mm |
Standover Height | — | 769mm |
Tire to Pedal Spindle | 80mm 170 mm cranks | 62.7mm -17.3mm 170 mm cranks |
Pedal Spindle to Ground Clearance | 94mm 170 mm cranks | 112mm +18mm 170 mm cranks |
Build
Wheel Size | 650B/27.5 in 584 mm BSD | 700C/29 in 622 mm BSD |
Tire Width | 47mm | 50mm +3mm |
Tire Outer Diameter | 678mm | 722mm +44mm |
Bike Length with Tires | 1686mm | 1726mm +40mm |
| 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://de.lightcarbon.com/uploadfile/downloads/2026-2027%20LightCarbon%20Frame+Component%20Catalog%20-V1.pdf |
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