Before
Our analysis of Marlin helped pinpoint the bike’s highest-impact parts so we could focus our efforts on reducing emissions where it matters most.
A Sustainable Shift: Trek’s low-impact aluminium bikes
When we conducted our first full emissions audit in 2021, we learned that aluminium was the single biggest contributor to our overall greenhouse gas emissions. So we’ve tackled this problem material head-on, rethinking everything about how and where we source aluminium. The key? It’s not just the material, but how it’s made.
We’ve created a new sustainable aluminium sourcing policy and are now getting aluminium from suppliers powered by renewable energy. In some cases, we’ve helped our partners upgrade their facilities to meet the higher environmental standards of our new standards.
This shift is making an impact. By February 2025, thousands of Trek city, mountain and road frames had been made with low-emission aluminium – and this was just the beginning.
Today, we’ve shifted nearly every aluminium bike frame we produce to low-emission material – marking the largest carbon-reduction initiative in Trek history and one of the most significant sustainability milestones in the cycling industry.
Here’s a closer look at our journey in pursuit of the world’s lowest-emission aluminium bike.
Same bikes. Made better.
Our path to low-emissions aluminium
Our most popular aluminium bike, by the numbers
Changes in emissions (kg CO2e) as per component on Gen 3 Marlin 5. An estimated reduction of 53.7% in CO2 emissions will be achieved after switching the components listed to low-carbon aluminium. Transition to low-carbon aluminium for parts is in process and in various stages of completion.
Fork
The Marlin's fork contains a large amount of aluminium, steel and magnesium, offering plenty of room for improvement. However, after researching our supply chain, we discovered that these forks are using post-consumer recycled materials in the castings, which places the emissions well within the suitable range.
Frame
Through supplier outreach, we discovered that our aluminium frames were being produced using carbon-intensive fossil fuels – most likely coal power. Since then, we’ve worked with multiple factories to implement a hydroelectric process that helps massively reduce frame emissions.
Rims, handlebar, seat post and stem
We are in the process of implementing low carbon aluminium in our rims, with plans to make changes to other parts as well.
Why is this in percentages?
We estimate product emissions by modelling production processes, materials and energy use. As we learn more, we refine our models for better accuracy. Since our 2021 report, we’ve updated Marlin's analysis four times. Showing reductions as percentages gives a clearer picture than using absolute numbers.
What kind of impact will low-emission aluminium have?
Nearly every Trek aluminium frame is now directly drawing down our footprint and bringing us closer to our climate goals. It’s a massive initiative with concrete results, and we want others in the industry and beyond to join us. Learn more in our most recent Sustainability Report.