Geometry ?
FiftyOne Assassin 2026 geometry in sizes S–XL: stack 540–620 mm, reach 375–430 mm, head angle 69.5°.
| S | M | L | XL | |
|---|---|---|---|---|
| Stack | 540 mm | 565 mm | 590 mm | 620 mm |
| Reach | 375 mm | 395 mm | 415 mm | 430 mm |
| Head angle | 69.5° | 69.5° | 69.5° | 69.5° |
| Seat angle | 73.5° | 73.5° | 73.5° | 73.5° |
| Seat tube (?) | 465 mm | 490 mm | 510 mm | 530 mm |
| Head tube | 116 mm | 141 mm | 170 mm | 202 mm |
| Top tube (effective) | 535 mm | 562.1 mm | 589.8 mm | 613.6 mm |
| BB drop | 70 mm | 70 mm | 70 mm | 70 mm |
| Chainstay | 430 mm | 430 mm | 430 mm | 430 mm |
| Wheelbase | 1023 mm | 1052.1 mm | 1081.7 mm | 1107.9 mm |
| Fork length | 405 mm | 405 mm | 405 mm | 405 mm |
(?) by the seat tube length: the manufacturer doesn’t say whether it’s measured centre to centre (c-c) or centre to top (c-t).
Source: storage.fiftyonebikes.com, checked 12 Nov 2026 · bar position: worked out from published data
Stock build
I don’t have the build for each size yet.
Frames with similar geometry
Stack and reach within 12 mm of size S (stack 540 / reach 375 mm).
Stack and reach within 12 mm of size M (stack 565 / reach 395 mm).
Stack and reach within 12 mm of size L (stack 590 / reach 415 mm).
Stack and reach within 12 mm of size XL (stack 620 / reach 430 mm).
Spotted a mistake or a missing build? Let me know.
Are you the manufacturer, or do you sell this bike? I’m missing 6 values for this model’s stem and bars. Add them