2025 Radon Bikes Spire Disc Carbon

	XS	S	M	L	XL
Stack	508mm	523mm	542mm	563mm	588mm
Reach	379mm	384mm	388mm	397mm	406mm
Stack to Reach Ratio	1.34:1	1.36:1	1.4:1	1.42:1	1.45:1
Seat Tube Length, Unknown	460mm	490mm	510mm	530mm	560mm
Top Tube Length, Effective/Horizontal Unknown	515mm	536mm	548mm	565mm	587mm
Top Tube Slope	7.3deg	5.7deg	5.7deg	5.8deg	5.3deg
Head Tube Angle	71.5deg	72.5deg	73deg	73.5deg	73.5deg
Seat Tube Angle	75deg	74deg	73.5deg	73.2deg	73deg
Head Tube Length	110mm	120mm	140mm	160mm	180mm
Bottom Bracket Drop	69mm	69mm	69mm	69mm	69mm
Bottom Bracket Height	270mm	270mm	270mm	270mm	270mm
Chainstay Length	408mm	408mm	408mm	408mm	408mm
Chainstay Length Horizontal	402.1mm	402.1mm	402.1mm	402.1mm	402.1mm
Front-Center	577mm	577mm	583mm	595.9mm	611.8mm
Front-Center Horizontal	572.9mm	572.9mm	578.9mm	591.9mm	607.9mm
Wheelbase	975mm	975mm	981mm	994mm	1010mm
Fork Offset/Rake	44.6mm	43.6mm	44.2mm	46.6mm	46.2mm
Trail	66.4mm high	61.2mm mid/neutral	57.4mm mid/neutral	51.9mm mid/neutral	52.3mm mid/neutral
Mechanical Trail	63mm	58.3mm	54.9mm	49.7mm	50.1mm
Wheel Flop	20mm	17.5mm	16mm	14.1mm	14.2mm
Standover Height	743mm	767mm	787mm	808mm	832mm
Tire to Pedal Spindle	68mm 170 mm cranks	68mm 170 mm cranks	74mm 170 mm cranks	86.9mm 170 mm cranks	102.8mm 170 mm cranks
Pedal Spindle to Ground Clearance	100mm 170 mm cranks	100mm 170 mm cranks	100mm 170 mm cranks	100mm 170 mm cranks	100mm 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://www.radon-bikes.de/roadbike-gravel/carbon/

Geometry