With the first generation of the Aethos, Specialized created a racing bike that achieved cult status right from the start. Launched four years ago, the model was the lightest production road bike for a long time, and by a wide margin. The bike had no other raison d'être. The geometry was copied from the professional Tarmac, which theoretically meant that it counted as a competition bike. However, according to the regulations, the bike is not only too light for this; the consistent focus on lightweight construction ignored the state of the art in aerodynamics, which is why - with additional weight - there was only one documented race use on a Tour de France stage, probably primarily for marketing reasons. Due to its good riding characteristics, the classic, minimalist look and the unrivalled low weight - one of the bikes we tested weighed just 6.1 kilograms in size 56 with Dura-Ace equipment - the bike nevertheless enjoyed great popularity among enthusiasts.
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The recently released professional models Scott Addict RC Ultimate (5.9 kilograms) and Cervélo R5 (6.0 kilograms) have now undercut this weight. They are not in direct competition with the Aethos, which has always been positioned as a bike for enthusiasts and recreational athletes. Nevertheless, the second generation of the Specialized should once again set new benchmarks. The frame of the top version, called S-Works, is said to weigh just 595 grams and is currently the lightest production frame in the world. Visually, it only appears to have been carefully modified. Striking aero profiles are still nowhere to be found; the classic, round tube and a traditional diamond frame shape dominate. A round seat post with clamp and a threaded BSA bottom bracket emphasise the reduction to the essentials. The brake lines integrated into the handlebars and stem are a tribute to modernity, as is the one-piece carbon cockpit for the top versions - the first generation did without this. Specialized claims to have saved weight, especially on the add-on parts: The carbon cockpit introduced with the Aethos is said to weigh 270 grams, while the new Alpinist CLX III wheelset now weighs 1131 grams for the front and rear wheels - that's more than 100 grams less, simply due to the use of new carbon spokes.
Light, but not lighter
Our test bike is equipped with the same groupset as the previous model, but a look at the TOUR scales reveals only minimal progress: the second generation is just 30 grams lighter. With a SRAM Red groupset and a smaller frame size, you could get close to the manufacturer's specification of 5.9 kilograms, but the new Aethos is not alone in this respect. The much more important innovation, however, concerns the geometry, which only becomes apparent once you're in the saddle. According to the manufacturer, it has been adapted for a wider range of customers based on data from Specialized's own Body Geometry bike fitting programme. Specifically, the riding position has been made significantly more comfortable: compared to its predecessor, the handlebars on the Aethos 2 are 15 millimetres higher for most frame sizes. This is still sporty, but is within the range of many prominent endurance models.
The much-praised precise handling of the Aethos is also said to be a hallmark of the new generation. We can largely confirm this, although the new Aethos is somewhat more good-natured than its nervous predecessor. A seven millimetre longer wheelbase and a slightly slacker steering angle improve smoothness on the straights. The bottom bracket has been lowered by three millimetres, which, according to Specialized, should result in more stable road holding in fast bends. The wider tyres also contribute to greater riding safety: 28 instead of 26 millimetres are now standard, and the frame and fork can accommodate tyres up to 35 millimetres wide. This means that the bike can also compete with marathon racers in terms of comfort. The 40 centimetre wide Alpinist Cockpit II is said to provide around 30 percent better damping than the aerodynamic Rapide cockpit familiar from the Tarmac. In the test lab, the Aethos actually performs remarkably well in terms of front comfort, making the bike feel better balanced on the road than many of its competitors: firm but not hard, both on the saddle and on the handlebars.
The S-Works bikes are traditionally not a bargain: the top versions with Shimano's Dura-Ace or SRAM Red AXS lead the portfolio, both costing €13,499. The Pro versions with heavier frames come with Shimano's Ultegra Di2 or SRAM Force AXS for €8,499 each and weigh around 6.7 kilograms. The cheapest version, called Expert, does without the Roval carbon cockpit and instead has classic clamped carbon handlebars. It costs 6299 euros and should weigh just over seven kilograms.
Specialized S-Works Aethos 2: Test grade, price, geometry, equipment, measured values, advantages and disadvantages
- Price: 2,699 Euro
- Weight of complete wheel: 6.1 kilos
- Frame sizes: 48, 51, 54, 56, 58, 61
- TOUR grade: 1,6
Geometry
- Seat/top/head tube: 510/57/170 millimetres
- Stack/Reach/STR: 589/385 millimetres/1.53
- Stack+/Reach+/STR+: 645/566 millimetres/1.14
- Wheelbase/caster: 997/66 millimetres
Equipment
- Drive/gear shift: Shimano Dura-Ace (2x12, 52/36, 11-30 t.) | Shimano Dura-Ace (2x12, 52/36, 11-30 t.) Note: 1,0
- Brakes: Shimano Dura-Ace (160/140 millimetres) Note: 1,5
- Tyres: Specialised S-Works Turbo TLR 28 millimetres | Note: 1,5
- Impellers: Roval Alpinist CLX III
- Impeller weights: 969/1269 grams (v./h.)
Measured values
- Weight of complete wheel: 6090 grammes | Note: 1,0
- Driving stability: 7.57 N/mm | Note: 2,0
- Rear comfort: 136 N/mm | Note: 2,0
- Comfort front: 90 N/mm | Note: 2,7
- Ride/ bottom bracket stiffness: 55 N/mm | Note: 2,0
Specialised S-Works Aethos 2: pros and cons
Advantages
Extremely light; lively but safe handling
Disadvantages
very expensive, tight gearing for an endurance bike
How TOUR tests
Jens Klötzer
Editor
