2025 Principia Gravel C20 Base

	50cm	52cm	54cm	56cm
Stack	581.5mm	597.7mm	609.4mm	628.3mm
Reach	369.6mm	379.4mm	387.6mm	396.5mm
Stack to Reach Ratio	1.57:1	1.58:1	1.57:1	1.58:1
Seat Tube Length, Unknown	500mm	520mm	540mm	560mm
Top Tube Length, Actual C-C	545mm	560mm	575mm	590mm
Top Tube Slope	11.3deg	10.7deg	9.7deg	9.4deg
Head Tube Angle	70.75deg	71.25deg	71.25deg	71.25deg
Seat Tube Angle	73.2deg	73.2deg	72.9deg	72.9deg
Head Tube Length	135mm	150mm	165mm	185mm
Bottom Bracket Drop	82.5mm	82.5mm	80mm	80mm
Bottom Bracket Height	271.5mm	271.5mm	274mm	274mm
Chainstay Length	435mm	435mm	435mm	435mm
Chainstay Length Horizontal	427.1mm	427.1mm	427.6mm	427.6mm
Front-Center	602.5mm	612.7mm	625.3mm	640.4mm
Front-Center Horizontal	596.8mm	607.1mm	620.1mm	635.4mm
Wheelbase	1023.9mm	1034.2mm	1047.7mm	1063mm
Fork Offset/Rake	50mm	50mm	50mm	50mm
Trail	70.7mm high	67.4mm high	67.4mm high	67.4mm high
Mechanical Trail	66.7mm	63.8mm	63.8mm	63.8mm
Wheel Flop	22mm	20.5mm	20.5mm	20.5mm
Standover Height	761.4mm	778.8mm	796.5mm	814.6mm
Tire to Pedal Spindle	78.5mm 170 mm cranks	86.2mm 172.5 mm cranks	98.8mm 172.5 mm cranks	111.4mm 175 mm cranks
Pedal Spindle to Ground Clearance	101.5mm 170 mm cranks	99mm 172.5 mm cranks	101.5mm 172.5 mm cranks	99mm 175 mm cranks

Very Upright

Somewhat Upright

Average

Somewhat Aggressive

Very Aggressive

The Bike Insights Upright/Aggressive scale is based on analysis of a bike’s proportions relative to similar sized bikes in the same category.

Category Trend

Source:https://principiabikes.com/gravel/gravel-carbon

Geometry