Geometry ?
Principia Gravel 30 2026 geometry in sizes 48–59: stack 557–642.8 mm, reach 366.3–400.2 mm, head angle 69.5–72°.
| 48 | 51 | 54 | 56 | 59 | |
|---|---|---|---|---|---|
| Stack | 557 mm | 579.8 mm | 602.8 mm | 621.7 mm | 642.8 mm |
| Reach | 366.3 mm | 370.7 mm | 382.2 mm | 391.7 mm | 400.2 mm |
| Head angle | 69.5° | 70.5° | 71.5° | 71.5° | 72° |
| Seat angle | 74° | 74° | 74° | 74° | 74° |
| Head tube | 115 mm | 135 mm | 155 mm | 175 mm | 195 mm |
| BB drop | 67 mm | 67 mm | 67 mm | 67 mm | 67 mm |
| Chainstay | 435 mm | 435 mm | 435 mm | 435 mm | 435 mm |
| Wheelbase | 1029.9 mm | 1030 mm | 1038.7 mm | 1054.6 mm | 1064.4 mm |
| Fork length | 425 mm | 425 mm | 425 mm | 425 mm | 425 mm |
| Fork offset | 45 mm | 45 mm | 45 mm | 45 mm | 45 mm |
Source: principiabikes.com, checked 13 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 48 (stack 557 / reach 366.3 mm).
Stack and reach within 12 mm of size 51 (stack 579.8 / reach 370.7 mm).
Stack and reach within 12 mm of size 54 (stack 602.8 / reach 382.2 mm).
Stack and reach within 12 mm of size 56 (stack 621.7 / reach 391.7 mm).
Stack and reach within 12 mm of size 59 (stack 642.8 / reach 400.2 mm).
Spotted a mistake or a missing build? Let me know.
Are you the manufacturer, or do you sell this bike? I’m missing 7 values for this model’s stem and bars. Add them