Sporting Goods — Hard (Bikes, Weights)

Material Composition Assumptions

The default bill of materials for a representative aluminum road bike (approximately 9 kg total) includes:

• Aluminum alloy frame and fork: Primary structural component, approximately 2.0–2.5 kg at 6061 or 7005 alloy grade. Primary aluminum contributes ~8–12 kgCO2e/kg; secondary (recycled) aluminum contributes ~0.5–1.0 kgCO2e/kg. A typical commercial frame uses a blend of approximately 70% primary and 30% recycled aluminum.
• Steel components (axles, bolts, cable housing): Approximately 0.8–1.2 kg of cold-rolled steel at roughly 2.0–2.5 kgCO2e/kg.
• Rubber tires: Two tires at approximately 0.5 kg each. Synthetic rubber production from petrochemical feedstocks contributes approximately 3.5–4.5 kgCO2e/kg.
• Drivetrain (cassette, chain, derailleurs, crankset): Mixed steel and aluminum components totalling approximately 1.5–2.0 kg, with precision manufacturing adding significant embedded energy.
• Wheels (rims, spokes, hubs): Typically aluminum rims with steel spokes, approximately 1.5–2.0 kg total.
• Plastics and composites (saddle, handlebar tape, shifter bodies): Approximately 0.5–0.8 kg of various polymers including polypropylene, nylon, and carbon-fibre-reinforced composite in premium models.
• Packaging: Cardboard box and foam inserts approximately 1.5–2.0 kg, with cardboard typically at 0.8–1.2 kgCO2e/kg.

The CCI score of 95 kgCO2e is calibrated to a mid-range aluminum road bike. Entry-level steel-frame bikes weigh more but use lower-carbon-intensity steel at scale (~60–70 kgCO2e total). High-end carbon fibre bikes weigh less overall but carbon fibre production is extremely energy-intensive (~20–30 kgCO2e/kg), pushing total footprint to 120–180 kgCO2e for full carbon frames.

Free weights and barbells follow a simpler material profile — predominantly steel or cast iron (~1.8–2.5 kgCO2e/kg) with minimal processing overhead — but their higher per-unit mass means total footprint scales directly. A standard 20 kg Olympic barbell set is approximately 40–50 kgCO2e; a full 100 kg weight set exceeds 200 kgCO2e.

Why the Score Is What It Is

Aluminum is the dominant driver of hard sporting goods emissions because primary aluminum smelting is among the most electricity-intensive industrial processes, consuming approximately 13–16 kWh per kilogram of metal produced. At a grid intensity of 565 gCO2e/kWh (China), this alone produces approximately 7–9 kgCO2e per kilogram of aluminum — before any forming, welding, or finishing. A 2.5 kg frame therefore carries approximately 18–22 kgCO2e in raw material alone, before the assembly plant ever opens its doors.

Component manufacturing adds substantial additional emissions. A bicycle drivetrain involves precision CNC machining, heat treatment, and surface coating of small steel and aluminum parts. The per-kg emissions of drivetrain components are higher than raw bar stock because manufacturing steps are energy-intensive relative to part mass. Shimano, SRAM, and Campagnolo components are predominantly manufactured in Asia under grid conditions that amplify Scope 2 contributions.

Wheel production combines aluminum rim extrusion (similar to frame manufacturing intensity), steel spoke drawing, and hub machining. Tires compound the impact: synthetic rubber derived from butadiene and isoprene feedstocks carries embedded fossil carbon from petrochemical refining, independent of the electricity grid.

Surface finishing — anodizing and powder coating — contributes approximately 15% of total emissions. Anodizing is an electrochemical process requiring significant current density; powder coating requires curing ovens at 160–200°C. Both processes are typically performed at separate facilities, adding transport steps and energy overhead.

Scope 1 emissions are relatively low (~5%) because most manufacturing processes at bicycle assembly plants are electric rather than combustion-based. The high Scope 3 share (~76%) reflects the globally distributed supply chain: aluminum smelted in China or the Middle East, components machined in Taiwan and Japan, tires made in Southeast Asia, and final assembly often in another country entirely.

What Drives Variation

Material choice is the strongest lever. Carbon fibre frames carry 20–30 kgCO2e/kg of embodied carbon, roughly double primary aluminum. The lower mass of a carbon frame (~1.0–1.5 kg) partially offsets this but does not close the gap at equivalent quality tiers. Steel frames (~60–70 kgCO2e total for an equivalent bike) are lower-carbon than aluminum equivalents at similar weights because steel has lower embodied energy per kilogram (~2–3 kgCO2e/kg vs. ~8–12 kgCO2e/kg for primary aluminum).

Recycled content in aluminum is transformative. Secondary (recycled) aluminum requires approximately 5–8% of the energy of primary smelting. Increasing recycled aluminum in the frame from 30% to 80% reduces frame-related emissions by approximately 35–40 kgCO2e — a meaningful fraction of the total product footprint. Trek’s e-bike frames increasingly use higher recycled content alloys, with disclosed reductions of 20–30% in frame manufacturing emissions.

Manufacturing location matters significantly for Scope 2. Frame welding and finishing in EU facilities (~300 gCO2e/kWh) rather than China (~565 gCO2e/kWh) reduces electricity-related emissions by approximately 47%. Some European bicycle manufacturers (e.g., Batavus, Gazelle in the Netherlands; Riese & Müller in Germany) maintain domestic assembly that reduces finished-goods transport and enables renewable energy procurement.

Product category within hard sporting goods creates wide variation. A set of steel dumbbells at 10 kg has a straightforward footprint of ~20–25 kgCO2e. A motorised exercise bike with electronics, wiring, and a display module may exceed 200 kgCO2e. Kayaks (polyethylene rotational moulding, ~15–30 kg HDPE) typically run 50–90 kgCO2e. The per-kg figure of 10.6 kgCO2e is most representative of fabricated metal-and-component products; simpler cast-metal goods will be lower.

Longevity and repairability significantly affect amortised emissions but fall outside the cradle-to-gate scope reported here. A bicycle used for 15 years and 30,000 km amortises its manufacturing footprint across a dramatically larger service boundary than one discarded after 2 years. Repairability (replaceable components vs. integrated assemblies) is therefore a meaningful but un-scored factor in product-level climate assessment.

Shipping mode for completed products affects the Scope 3 logistics contribution substantially. Ocean freight from Asia to Europe or North America contributes approximately 0.01–0.03 kgCO2e/kg per 1,000 km — modest relative to manufacturing, but adds up for 9 kg products over 15,000 km transoceanic routes. Air freight (used for premium and time-sensitive shipments) is roughly 50–80× more carbon-intensive per tonne-km.

Methodology Notes

• CCI score of 95 kgCO2e represents a mid-range estimate for a standard 9 kg aluminum road bike, cradle-to-gate. Published LCA and sustainability report data ranges from ~60 kgCO2e (steel frame, domestic EU production) to ~180 kgCO2e (full carbon fibre, Asian production).
• Scope breakdown: Scope 3 dominates at ~76% (72 kgCO2e), driven by upstream material extraction, component manufacturing, and outbound logistics. Scope 2 accounts for ~19% (18.5 kgCO2e) from finishing and assembly electricity. Scope 1 is ~5% (4.5 kgCO2e) from process heat.
• Functional unit: One complete aluminum road bicycle, approximately 9 kg assembled, cradle-to-gate (retail delivery excluded unless stated).
• Confidence is medium because bicycle supply chains are complex and multi-tiered, few manufacturers publish full product-level LCAs, and the contribution of component sourcing is difficult to verify without primary data from Tier 2 and Tier 3 suppliers.
• Category breadth: Hard sporting goods span a very wide range of materials, masses, and manufacturing intensities. The per-kg figure of 10.6 kgCO2e/kg is most applicable to fabricated metal-dominant products; adjustments are needed for pure cast-iron, composites, or electronic-heavy categories.