Recycled aluminium has become cycling’s favourite sustainability headline — but not all “recycled” aluminium is created equal. Independent design engineer Matt Granger of Venn Projects, formerly Islabikes and KISKA, explores what’s real, what’s marketing, and how the trade can navigate the growing pressure for genuine circularity.
Aluminium has long been cycling’s workhorse — lightweight, affordable, and easy to manufacture. Add its reputation for infinite recyclability, and it seems like a sustainability no-brainer. Around 75% of all aluminium ever produced is still in use, and recycling it uses up to 95% less energy than primary smelting.
But while the numbers sound great, turning that promise into high-performance bike components is far from straightforward.
The Brompton example
When Brompton and Norsk Hydro launched rims made from 100 % post-consumer recycled (PCR) aluminium, it grabbed attention — and rightly so. Yet it also raised the question: if PCR aluminium works for rims, why not for frames?
The answer comes down to alloy chemistry and consistency. Many frames rely on 6061-series aluminium for its balance of strength, weldability and fatigue life. Even trace impurities from recycled scrap can cause brittleness or poor weld performance. Rims are more forgiving; frames are not.
Why it’s harder than it looks
Many “recycled aluminium” claims actually refer to post-industrial scrap — clean off-cuts from factories that are easy to re-melt. True PCR aluminium, taken from products at end of life, contains a mix of alloys and contaminants that are difficult to separate.
One such example is the small difference in grade depending on whether the aluminium is being forged or cast. For the latter, increased amounts of silicon are added to improve flow through the tool. This doesn’t contribute to the mechanical strength of the material and, therefore, isn’t desirable in a recycled material blend.
Emerging technologies such as Laser-Induced Breakdown Spectroscopy (LIBS) can now sort alloys in real time, allowing higher-purity recycled feedstock. But these systems are expensive, and few suppliers in the bike industry have adopted them.
The supply chain blind spot
Most brands only see as far as their frame factory. The origin of the metal — buried three or four tiers deeper — is often opaque. That makes it almost impossible for smaller brands to specify or verify genuine PCR content.
This lack of visibility feeds another issue: greenwashing risk. As consumers and retailers grow more aware of sustainability claims, loose terminology can backfire. Calling post-industrial scrap “recycled” might satisfy marketing, but it erodes trust if people look closer.
“Recycled aluminium isn’t a miracle cure — but it’s no myth either. It’s a material on the brink of becoming truly circular, if the industry can align technology, transparency and design.”
Signs of progress
There are encouraging examples. Moustache Bikes’ new J model uses a cast-aluminium frame made from a single alloy, simplifying recycling and reducing production waste. It shows that real circularity might come from re-engineering how frames are made, not just the material they’re made from.
What the trade can do now
• Designers and engineers: minimise mixing of cast and extruded parts if recyclability is a goal.
• Marketers: distinguish clearly between post-consumer and post-industrial content — and explain the difference.
• Brand leaders and retailers: push for traceability. Knowing your material’s true origin will soon matter as much as knowing your cost base.
Closing the loop
Recycled aluminium can genuinely cut emissions and resource use — but only if the industry tackles the chemistry, the supply chain, and the communication all at once. The brands that do will own the next chapter of cycling’s sustainability story.
About the author
Matt Granger is an independent design engineer and founder of Venn Projects, a contract service working at the intersection of product design, engineering, net positive practice and circular manufacturing. Venn helps brands turn sustainability ambition into a manufactured reality.
This feature is an executive summary of the full article available on the Venn Projects website.
