Commuter Bicycle

Material Composition Assumptions

The baseline commuter bicycle consists of several key material components that drive manufacturing emissions. The aluminum alloy frame represents the largest single component at approximately 8,000-10,000 grams, comprising 40-50% of total material weight. Steel components including wheels, drivetrain, and hardware account for 5,000-6,000 grams or 25-30% of the bicycle. Rubber materials for tires and inner tubes contribute 2,000-3,000 grams representing 10-15% of total weight. Plastic components including grips, saddle, and various accessories make up 1,000-2,000 grams or 5-10% of the final product. High-end models may incorporate carbon fiber elements, though this material is excluded from the baseline assessment due to its premium positioning and significantly higher emissions profile.

Manufacturing Geography

China dominates global bicycle production with approximately 90% of manufacturing capacity concentrated in industrial regions including Jiangsu, Zhejiang, and Guangdong provinces. The electrical grid intensity of 555 gCO2/kWh significantly influences manufacturing emissions, particularly for aluminum frame production which requires substantial energy for smelting and forming processes. This geographic concentration emerged due to established supply chains for components, skilled labor availability, and proximity to raw material processing facilities. The integration of frame manufacturing, component assembly, and finishing operations within concentrated industrial zones creates efficiency benefits while embedding the regional carbon intensity into product emissions profiles.

Regional Variation

Manufacturing Region	Grid Intensity	Estimated CCI Score	Adjustment vs Default
China	555 gCO2/kWh	48 kg CO2e	Baseline
Taiwan	509 gCO2/kWh	44 kg CO2e	-8%
European Union	276 gCO2/kWh	35 kg CO2e	-27%
United States	386 gCO2/kWh	40 kg CO2e	-17%
India	708 gCO2/kWh	55 kg CO2e	+15%

Provenance Override Guidance

1. Frame material specification and weight documentation including alloy composition, manufacturing process details, and supplier-specific emissions factors for aluminum or steel production facilities.

2. Component sourcing documentation with detailed breakdown of wheel manufacturing, drivetrain specifications, and supplier emissions data for major subassemblies including hubs, spokes, and gear systems.

3. Manufacturing facility energy profile including renewable energy procurement, grid intensity data, and facility-specific electricity consumption measurements during production cycles.

4. Transportation and logistics documentation covering shipping methods, distances from component suppliers to assembly facilities, and distribution channels to final markets.

5. End-of-life material recovery data including aluminum recycling rates, component refurbishment programs, and documented material flow analysis for returned or discarded bicycles.

Methodology Notes

• The CCI score represents cradle-to-gate manufacturing emissions for a standard 20-kilogram commuter bicycle with aluminum frame and steel components, excluding use phase and end-of-life impacts.

• Scope 2 emissions dominate the profile due to energy-intensive aluminum production and component manufacturing processes, while Scope 1 and 3 emissions are minimal in the manufacturing phase.

• The functional unit assumes a typical commuter bicycle design suitable for urban transportation with standard components and accessories.

• Exclusions include specialized performance components, electric assist systems, and premium materials such as titanium or advanced carbon fiber composites.

• Data gaps exist for component-specific supplier emissions, recycled content percentages, and regional variations in assembly processes across different manufacturing facilities.