The lightest series frame on the planet is renewed: Specialized Aethos 2

Road 02/10/25 18:00 Migue A.

4 years ago, Specialized looked back to manufacture a bike, in front of increasingly aerodynamic and efficient sports models, a bike with pure, simple lines, and above all, extremely light. Now, the Californian brand renews its Aethos, bringing it up to date without losing that unbeatable weight that has made it a desirable object for many cyclists.

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Specialized's lightest bike adapts to a greater number of cyclists

After 4 years on the market, the concept with which Specialized created the Aethos remains fully valid. While competition bikes continue to be the desire of many road cyclists looking to emulate their idols, it is also true that the increasingly complex and elaborate aerodynamic lines are not to the liking of those who long for the simplicity and clean lines of traditional bikes, and above all, the lightness that could be achieved in top-of-the-range bikes before the arrival of disc brakes or internal cabling.

That is why this new Specialized Aethos 2 maintains an evident continuity with the previous model, updating the details that add value while keeping unchanged the aspects that give it its own identity.

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Obviously, the essence of its weight is the ultralight weight, 5.98 kg in the top-of-the-range standard assembly that remains unchanged in this new version despite introducing features that always translate into an increase in grams on the scale, such as fully internal cabling from end to end or providing it with larger wheel clearances.

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To achieve this, Specialized has taken a step forward in its engineering process, which they have called Flow State Design, pushing their computer simulations to the limit with data collected over decades of bike manufacturing, improving their understanding of how different forces affect the structure of carbon frames, allowing them to further optimize both the shape and the layup of this new Aethos 2.

595 grams of frame is the incredible resulting figure of this process, a spectacular data considering that it continues to maintain its tremendous rigidity and strength despite one of the main evolutions in the layup of its frame being precisely the elimination of the extra layers that finish the assembly in the usual construction of frames seeking to consolidate rigidity. Unnecessary with the new layup, allowing for weight savings. Of course, all this under the Rider First Engineering premises that involve individualized layup for each frame size so that they all have the same behavior.

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Adapting this new Specialized Aethos 2 to a greater number of cyclists has been another of the objectives that the Morgan Hill brand has sought in this revision of its lightest bike. For this, they have made slight adjustments to the geometry that soften it slightly but not to the extent of losing its agile behavior as a true climbing bike.

To determine these changes, Specialized has leveraged Body Geometry data from over 100,000 biomechanical studies. The result is that this new Aethos 2 has a slightly higher stack, 15 mm. The pedal axis height is lowered by 3 mm to improve stability, the same goal is pursued by opening half a degree the steering angle and the chainstays, which grow by 7 mm, which, of course, also has an effect on an increase in the wheelbase length.
Changes in the geometry are also aimed at adapting the bike to a larger wheel clearance that allows this Aethos 2 to mount tires up to 700x35 to satisfy those looking for a more all-road use in this bike.

Following the trend in recent bike models, Specialized also equips this Aethos 2 with a UDH-type dropout, which will allow, in addition to opting for conventional road groups, to install if desired a single-chainring configuration with the new 13-speed gravel groups from SRAM and their full-mount type derailleurs. By the way, speaking of assemblies, it is worth noting in its S-Works version the presence of the new Alpinist II cockpit and the Roval Alpinist III wheels weighing only 1,131 g.