	45	48	51	53	56	58	61
Stack	538.9mm	538.9mm	563.4mm	575.9mm	602.4mm	625.4mm	650.4mm
Reach	371.1mm	371.1mm	374.5mm	380.4mm	382.1mm	384.4mm	385.5mm
Stack to Reach Ratio	1.45:1	1.45:1	1.5:1	1.51:1	1.58:1	1.63:1	1.69:1
Seat Tube Length, C-T	450mm	480mm	510mm	530mm	560mm	580mm	610mm
Top Tube Length, Effective/Horizontal Center	505mm	515mm	525mm	545mm	560mm	575mm	590mm
Top Tube Slope	12deg	8.6deg	8deg	7.2deg	6.9deg	7.3deg	6.9deg
Head Tube Angle	71.8deg	71.8deg	72deg	72.3deg	73.5deg	73.5deg	74deg
Seat Tube Angle	76deg	75deg	75deg	74deg	73.5deg	73deg	72.5deg
Head Tube Length	125mm	125mm	150mm	162mm	180mm	204mm	228mm
Bottom Bracket Drop	75mm	75mm	75mm	75mm	75mm	75mm	75mm
Bottom Bracket Height	268mm	268mm	268mm	268mm	268mm	268mm	268mm
Chainstay Length	404mm	404mm	404mm	404mm	406mm	410mm	410mm
Chainstay Length Horizontal	397mm	397mm	397mm	397mm	399mm	403.1mm	403.1mm
Front-Center	576.9mm	576.9mm	586.4mm	593.2mm	590mm	599mm	602mm
Front-Center Horizontal	572mm	572mm	581.6mm	588.4mm	585.2mm	594.3mm	597.3mm
Wheelbase	969mm	969mm	978.6mm	985.4mm	984.2mm	997.4mm	1000.4mm
Fork Offset/Rake	48mm	48mm	48mm	48mm	48mm	48mm	48mm
Fork Length (On-Axis)	576.9mm	576.9mm	576.9mm	576.9mm	576.9mm	576.9mm	576.9mm
Trail	62.2mm mid/neutral	62.2mm mid/neutral	61mm mid/neutral	59.1mm mid/neutral	51.5mm mid/neutral	51.5mm mid/neutral	48.4mm mid/neutral
Mechanical Trail	59.1mm	59.1mm	58mm	56.3mm	49.4mm	49.4mm	46.5mm
Wheel Flop	18.5mm	18.5mm	17.9mm	17.1mm	14mm	14mm	12.8mm
Tire to Pedal Spindle	63.9mm 170 mm cranks	63.9mm 170 mm cranks	73.4mm 170 mm cranks	80.2mm 170 mm cranks	77mm 170 mm cranks	86mm 170 mm cranks	89mm 170 mm cranks
Pedal Spindle to Ground Clearance	98mm 170 mm cranks	98mm 170 mm cranks	98mm 170 mm cranks	98mm 170 mm cranks	98mm 170 mm cranks	98mm 170 mm cranks	98mm 170 mm cranks

	45	48	51	53	56	58	61
Wheel Size	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD
Tire Width	32mm	32mm	32mm	32mm	32mm	32mm	32mm
Tire Width Max	35mm	35mm	35mm	35mm	35mm	35mm	35mm
Tire Outer Diameter	686mm	686mm	686mm	686mm	686mm	686mm	686mm
Bike Length with Tires	1655mm	1655mm	1664.6mm	1671.4mm	1670.2mm	1683.4mm	1686.4mm

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.

Learn more about the Upright/Aggressive Scale

Category Trend

Endurance Road

Source:https://bassobikes.com/en/bikes/road-bikes/astra

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2026 Basso Bikes Astra Base

Geometry

Base Build

Stack and Reach vs. Category Trend