Lightweight road bike under 6 kilos: Specialized Aethos 2 - more than uncompromisingly light

"Perfection is not achieved when nothing more can be added, but when nothing more can be left out" - with this philosophical quote from the French writer Antoine de Saint-Exupéry, author of the famous novel "The Little Prince", Specialized introduces the presentation of the new Aethos. With the second generation of the lightweight racer, the US manufacturer is also pursuing a seemingly philosophical goal: the Aethos 2 is intended to be more than just an uncompromisingly lightweight racing bike, but to open the door to a riding experience that is reduced to the absolute essentials - as the press release states.

Specialised Aethos II: The most important facts

• Weight of complete wheel: from approx. 5.9 kilograms (size 56)
• Frame weight: 595 grams (S-Works), 795 grams (Pro, Expert)
• Stack/Reach/STR: 580/391 millimetres/1.48 (size 56)
• Frame sizes: 49, 52, 54, 56, 58, 61 centimetres
• Prices complete wheel: 6299 to 13,499 euros
• Prices frameset: 3799 or 5499 euros (S-Works)

The model, which was first introduced four years ago, was the lightest road bike from a series manufacturer for a long time, and by a wide margin. One of the bikes we tested weighed just 6.1 kilograms in size 56 with Dura-Ace equipment. With the recently released models Scott Addict RC Ultimate (5.9 kg), which secured a top score in the TOUR testand Cervélo R5 (6.0 kilograms) the mark has now been broken.

These dedicated competition models are not in direct competition with the Aethos, which has always been positioned as a bike for enthusiastic recreational athletes. Nevertheless, the second generation of the Aethos is set to set new benchmarks with the art of omission: According to Specialized, at 5.9 kilograms, the new Aethos 2 is the brand's lightest road bike to date.

Lightest frame in the world?

The Americans are obviously aware that the current top weights of the competition cannot be significantly undercut again. The S-Works frame of the Aethos made from Fact-12r carbon is said to weigh just 595 grams, making it currently the lightest production frame in the world.

At 705 grams, the "normal" Factr-10r version is still very light in the market environment, where aerodynamically designed carbon frames weigh around 1000 grams on average. However, Specialized emphasises that weight records were not the only focus in the development of the new Aethos.

Cautious modernisation

The frame only appears to have been carefully modified: You will continue to look in vain for striking aero profiles; the classic, round tube and traditional diamond geometry dominate. The brake lines integrated into the handlebars and stem are a tribute to modernity, as is the one-piece carbon cockpit on the top version - the first generation did without this for weight reasons. However, the Aethos still has a round seatpost with a classic clamp and a threaded BSA bottom bracket.

New geometry for a more relaxed ride

Significant changes to the predecessor model concern the geometry, with which Specialized is probably responding to the demands of the target group: The much-praised precise handling of the Aethos is said to have remained a feature of the new generation. However, the geometry has been adapted for a larger customer base based on data from the in-house bike fitting programme called Body Geometry. According to the manufacturer, 100,000 data sets were analysed for this purpose.

In concrete terms, this means above all that the riding position has become more comfortable: compared to its predecessor, the Aethos 2 offers 15 millimetres more stack for most frame sizes. Only for the two smallest sizes 49 and 52 is the stack slightly less. Specialized has thus positioned the bike even more clearly as an endurance model than before; the original model still had a competition-oriented geometry.

Other changes include a seven millimetre longer wheelbase and a 0.5 degree slacker steering angle, which makes for a smoother ride on the straights. The bottom bracket has been lowered by three millimetres, which Specialized hopes will result in more stable road holding in fast bends. The space for wider tyres is also geared towards modern requirements: 35 millimetres now fit through the frame and fork.

Lightweight wheels and new handlebars from Roval

The presentation of the Aethos 2 is accompanied by the new handlebar/stem unit and a new wheelset from Roval. Both are called Alpinist, which refers to the brand's lightest components, and are also available as separate components. A 40 centimetre wide Alpinist Cockpit II is said to weigh 270 grams and offer around 30 percent more damping than the Tarmac SL8. Click here to test the race all-rounder - well-known aerodynamic Rapide cockpit. With a classic 1-1/8-inch clamp, it is also compatible with other bikes. With the exception of the cheapest "Expert" version, it is fitted to all equipment variants of the Aethos 2.

The Alpinist CLX III wheelset, now weighing 1,131 grams for the front and rear wheels, is also said to have saved weight: More than 100 grams through the use of new carbon spokes alone. In addition, lighter hubs are used, the inner workings of which come from supplier DT Swiss. The rim remains unchanged. The new wheelset is only available in the expensive S-Works versions.

Specialised Aethos 2: Features and prices

Frame sets for self-assembly are also offered for both available qualities: The base of the "Pro" and "Expert" for 3799, the lighter top model S-Works for 5499 euros. The top versions S-Works Aethos 2 with Shimano Dura-Ace or SRAM Red AXS lead the portfolio of complete offers. Both bikes cost the same: 13,499 euros. The weights are specified at around six kilograms each. The Pro versions with a heavier frame come with Shimano's Ultegra Di2 or SRAM Force AXS for 8499 euros each and a total weight of around 6.7 kilograms. The "entry-level version" called Expert does without the Roval carbon cockpit and instead offers a classic clamped carbon handlebar. It costs 6299 euros and is said to weigh just over seven kilograms. An Expert version with SRAM Force, which is also listed in the press release, is not officially available in Europe.

S-Works Aethos 2 - Shimano Dura-Ace Di2

• Drive/gear shift: Shimano Dura-Ace (2x12, 52/36, 11-30 t.)
• Brakes: Shimano Dura-Ace (160/160 mm)
• Tyres: S-Works Turbo TLR (28 mm)
• Impellers: Roval Alpinist CLX III (Carbon)
• Price: 13,499 Euro
• Weight: 5.98 kilogrammes (size 56)

S-Works Aethos 2 - SRAM Red AXS

• Drive/gear shift: SRAM Red AXS (2x12; 48/35, 10-33 t.)
• Brakes: SRAM Red AXS (160/160 mm)
• Tyres: S-Works Turbo TLR (28 mm)
• Impellers: Roval Alpinist CLX III (Carbon)
• Price: 13,499 Euro
• Weight: 6.05 kilogrammes (size 56)

Aethos 2 Pro - Shimano Ultegra Di2

• Drive/gear shift: Shimano Ultegra (2x12, 52/36, 11-30 t.)
• Brakes: Shimano Ultegra (160/160 mm)
• Tyres: S-Works Turbo TLR (28 mm)
• Impellers: Roval Alpinist CL II (Carbon)
• Price: 8499 Euro
• Weight: 6.73 kilogrammes (size 56)

Aethos 2 Pro - SRAM Force AXS

• Drive/gear shift: SRAM Force AXS (2x12; 48/35, 10-33 t.)
• Brakes: SRAM Force AXS (160/160 mm)
• Tyres: S-Works Turbo TLR (28 mm)
• Impellers: Roval Alpinist CL II (Carbon)
• Price: 8499 Euro
• Weight: 6.71 kilogrammes (size 56)

Aethos 2 Expert - Shimano Ultegra Di2

• Drive/gear shift: Shimano Ultegra (2x12, 52/36, 11-30 t.)
• Brakes: Shimano Ultegra (160/160 mm)
• Tyres: S-Works Turbo (28 mm)
• Impellers: Roval C38 (Carbon)
• Price: 6299 Euro
• Weight: 7.12 kilogrammes (size 56)