Overview of the Specialized Bicycles Podcast: Aethos 2
Specialized Bicycles recently released a podcast diving deep into the engineering and philosophy behind the new Aethos 2 road bike. Host Ben Capron sat down with Seb Servais (Lead Road Engineer) and Alex Jerome (Road Product Leader) to uncover how they refined a bike already celebrated for its pure, uncluttered riding experience.
Here is a summary of the key takeaways from the conversation, detailing how Specialized achieved a new level of perfection in lightweight performance.
Key Takeaways from the Podcast:
1. The Aethos Philosophy: Engineered to Disappear
The Aethos is not built for the finish line; it’s built for the sheer joy of riding. Alex Jerome explained the core difference between the Aethos and the race-focused Tarmac:
- Tarmac Rider: Focused on the World Tour, speed, aerodynamics, and achieving clear, win-or-lose objectives.
- Aethos Rider: Seeks "pure simplicity and enjoyment," demanding compliance, comfort, and handling for a deeply personal, "magical" ride.
The design goal was for the bike to "disappear underneath you", achieving perfection by having "nothing left to take away". This approach resulted in an unbelievably light machine:
- Frame Weight: 595 grams—too light to be raced by the UCI.
- Complete Weight (S-Works): Approximately 5.9-6 kg (just over 13 pounds).
2. Refinements for Aethos 2
The Aethos 2 is a targeted refinement of its predecessor, with several tweaks designed to enhance stability and fit:
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Slacker Head Tube Angle: The head tube angle was slackened by half a degree to provide "a little bit more stability" and confidence, especially when descending, a change discovered through iterative prototyping and ride-testing.
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Increased Stack Height: Based on Specialized's extensive Body Geometry (BG) fit data, 15mm of stack was added to the head tube. This change addresses the fact that many riders were adding spacers to the original Aethos, and now allows more riders to achieve a comfortable, better-looking fit with fewer spacers.
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Modern Standards: The new frame incorporates a Universal Derailleur Hanger (UDH) and increases tire clearance up to 35mm.
3. The Engineering Breakthrough: Flow State Design
The core of the Aethos’s record-breaking weight lies in an engineering breakthrough Seb Servais and his team call "Flow State Design."
The initial insight came from observing a Tarmac SL6 frame on a test bench, where certain tube areas were "breathing" or flexing while others were not. This indicated an inefficient distribution of load.
To solve this, the team decided to design tubes that would distribute stress evenly across the entire frame. This required:
- Computational Power: Partnering with external companies to access supercomputers to run massive amounts of Finite Element Analysis (FEA) simulations.
- Iterative Optimization: The computer was tasked with determining the ideal tube shape to carry the load more efficiently, leading to the elimination of entire plies of carbon material that had previously been required.
- Cross-Platform Learning: The knowledge gained from this "Flow State" process was so significant that it was later applied to the development of the Tarmac SL8, informing future Specialized frame designs.
4. A Holistic, Integrated System
The Aethos 2 is a complete system, with Specialized's Roval components enhancing the ride quality:
- New Alpinist Cockpit: Designed using Retül fit data, the new one-piece bar and stem is more compliant than the aero-focused Rapide cockpit, prioritizing comfort and aesthetics.
- Updated Alpinist Wheelset: Features new hubs and, most notably, carbon spokes. These spokes dramatically save weight and—crucially—mediate the way loads are transferred, resulting in an "extremely precise" and pure ride quality.
5. Rider-First Engineering
A foundational philosophy for Specialized, Rider-First Engineered principles ensure that the ride quality is consistent for every rider, regardless of size.
Alex Jerome noted that to achieve this "great experience for every rider," Specialized doesn't simply scale frames up and down. Instead, every frame size (from a 49 to a 61) receives a unique carbon layup, guaranteeing that every individual feels the same balanced stiffness and handling. As Remco Evenepoel's words were recalled, for both competitive and enthusiast riding, "Comfort is performance".
The Aethos 2 represents a deep devotion to the craft of cycling, combining cutting-edge technology and data with the human intuition of expert riders to deliver a machine that inspires the deepest connection to the road. The Aethos is not just about being light, it is about an unparalleled ride feel that surpasses its predecessors. You can watch the full podcast here:
The Specialized Bicycles Podcast: Aethos 2