2026 Principia Gravel 30 Base

	48cm	51cm	54cm	56cm	59cm
Stack	557mm	579.8mm	602.8mm	621.7mm	642.8mm
Reach	366.3mm	370.7mm	382.2mm	391.7mm	400.2mm
Stack to Reach Ratio	1.52:1	1.56:1	1.58:1	1.59:1	1.61:1
Seat Tube Length, C-T	480mm	510mm	540mm	560mm	590mm
Top Tube Length, Effective/Horizontal Center	526mm	537mm	555mm	570mm	584.5mm
Top Tube Slope	10.9deg	9.9deg	9deg	8.7deg	7.7deg
Head Tube Angle	69.5deg	70.5deg	71.5deg	71.5deg	72deg
Seat Tube Angle	74deg	74deg	74deg	74deg	74deg
Head Tube Length	115mm	135mm	155mm	175mm	195mm
Bottom Bracket Drop	67mm	67mm	67mm	67mm	67mm
Bottom Bracket Height	289mm	289mm	289mm	289mm	289mm
Chainstay Length	435mm	435mm	435mm	435mm	435mm
Chainstay Length Horizontal	429.8mm	429.8mm	429.8mm	429.8mm	429.8mm
Front-Center	603.8mm	604mm	612.6mm	628.4mm	638.1mm
Front-Center Horizontal	600.1mm	600.2mm	608.9mm	624.8mm	634.6mm
Wheelbase	1029.9mm	1030mm	1038.7mm	1054.6mm	1064.4mm
Fork Offset/Rake	45mm	45mm	45mm	45mm	45mm
Fork Length, Unknown	425mm	425mm	425mm	425mm	425mm
Trail	85.1mm very high	78.3mm high	71.7mm high	71.7mm high	68.4mm high
Mechanical Trail	79.7mm	73.8mm	68mm	68mm	65mm
Wheel Flop	27.9mm	24.7mm	21.6mm	21.6mm	20.1mm
Tire to Pedal Spindle	77.8mm 170 mm cranks	78mm 170 mm cranks	86.6mm 170 mm cranks	102.4mm 170 mm cranks	112.1mm 170 mm cranks
Pedal Spindle to Ground Clearance	119mm 170 mm cranks	119mm 170 mm cranks	119mm 170 mm cranks	119mm 170 mm cranks	119mm 170 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-aluminium/gravel-30---black-pg-2592

Geometry