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
Emissions audit
In 2021, we discovered that aluminium was the top contributor to our overall emissions. Much of the aluminium that we were using was made at facilities powered by fossil fuels, which is common in the the bike industry and beyond. But when that aluminium is made using renewable energy, the overall impact decreases significantly.
Supplier outreach programme
So, we launched a massive supplier outreach effort. We dug in and asked questions that hadn't been asked before and learnt a lot along the way. This work has given us a clearer picture of our supply chain: both good and bad.
Developed training
We teamed up with the Dutch non-profit Shift Cycling Culture, the German development agency GIZ and other bike brands to develop training on the core concepts of sustainability, carbon accounting, regulatory guidance and data analysis to help our suppliers identify the biggest impact areas in our operations.
All-new sourcing policy
At the same time, we created an all-new aluminium sourcing policy that ensures our partners in the supply chain are as dedicated as we are to lowering emissions. The policy gives us better transparency into our Scope 3 emissions and outlines clear requirements regarding the acceptable emission levels of our products.
First low-emission aluminium bike
The first low-emission aluminium bike frames are already available at Trek retailers, and low-emission material is the default for nearly every alloy bike we make. Next, we’re exploring beyond the frame to see how we can lower the impact of other alloy parts.
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.
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.
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.
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.
We are in the process of implementing low carbon aluminium in our rims, with plans to make changes to other parts as well.
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.