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Cycling Weekly

Sport

Aaron Borrill

Specialized S-Works Aethos 2 review: is this the perfect road bike?

Specialized SRAM Richard Butcher Aaron Borrill Roval (Organization) Shimano STEM

In a world forcing the aerodynamic performance narrative, the Specialized Aethos is a breath of fresh air, eschewing the mainstream dropped seatstay and deep headtube configurations of contemporary road bikes for classic double-diamond architecture. The first-generation Aethos, launched in 2020, was a hit among purists and, in many ways, close to the best lightweight bike in terms of rider enjoyment – perhaps even perfect.

Specialized was careful not to lose those attributes with the new model, but was also keen to modernise the platform, which now gains an integrated cockpit, wider tyre clearances, subtle tweaks to the geometry and a carbon layup inspired by the S-Works Tarmac SL8 race bike.

Despite these alterations, the lightweight ethos and character of the original Aethos remain unchanged, as does the exorbitant sticker price of the S-Works derivative. As expected from a Halo bike, it gets all the bells and whistles, but is there anything to be gained or lost looking further down the range?

The head angle of the Specialized S-Works Aethos 2 has been slackened from 73 to 72.5 degrees, while the wheelbase has grown 14mm to 992mm (Image credit: Richard Butcher)

Technical details

One of Specialized’s main focuses for the new Aethos is centred on creating a better fit, drawing on decades’ worth of Body Geometry fit data and over 100,000 fit studies. These values have culminated in a less aggressive, more stable platform across all sizes, thanks to a 15mm taller stack (13-15mm depending on size), a longer wheelbase, a slightly relaxed head angle, and a lower bottom bracket height – the latter of which should help it find favour with more riders.

To counter the added mass of the new UDH dropout, internal hosing, and increased stack height, the Aethos employs a Tarmac SL8-inspired layup with new tube shapes and ply placements that take up structural loads. The new frame is just 10g heavier than its forebear at 595g. The total system weight in SRAM Red AXS guise comes in at 5.98g in size medium, with tubeless tyres (and sealant) fitted. Despite its feathery intentions, it loses out to the 5.88kg Scott Addict RC Ultimate in the same size, but trumps the 6.3kg Cannondale Lab71 SuperSix Evo SL.

The front end uses a Roval Alpinist Cockpit II with totally hidden hoses (Image credit: Richard Butcher)

Despite the subtle changes to the tube shapes, some will find it difficult to tell the Aethos 2 apart from its predecessor, but to me, that’s a good thing. I appreciate the classic lines and clean silhouette that have all but disappeared from the pro peloton. The range-topping S-Works Aethos 2 is available in two colourways, depending on your groupset persuasion: SRAM Red AXS builds come in ‘Red Tint’, and Shimano Dura-Ace Di2-equipped models are painted in a pastel turquoise called ‘Fjord Metallic’.

The frame angles are not too different from those of the previous-generation Aethos. In size 54cm, the reach is identical at 384m, but the stack has increased from 544mm to 559mm. The head angle has been slackened from 73 to 72.5 degrees, while the wheelbase has grown 14mm to 992mm. While the chainstays remain at 410mm, the most notable change is an increase in tyre clearance from 32mm to 35mm, essentially future-proofing the platform for years to come.

At the heart of the S-Works Aethos 2 lies a SRAM Red AXS groupset with a 48/35T, 11-33T chainset and Quarq power meter (Image credit: Richard Butcher)

Specifications

As a S-Works model, the Aethos 2 comes loaded with top-level kit - in this case, a SRAM Red AXS with a 48/35T, 11-33T chainset and Quarq power meter. We’ve waxed lyrical about the precision and smooth operation of this groupset, and the modulation of the powerful braking system continues to impress. The bike rolls on a pair of Roval Alpinist CLX III wheels shod with 28mm S-Works Turbo TLR Race tyres.

Owing to the push for complete system integration, the front end uses a Roval Alpinist Cockpit II with totally hidden hoses. The balance is rounded off with Supacaz bar tape, a SRAM DUB BSA 68 bottom bracket and S-Works Power with Mirror 3D-printed saddle.

With a system weight of 5.88kg (6kg with pedals), the hills and mountains are its natural habitat; it's pretty decent on the flats, too (Image credit: Aaron Borrill)

Performance

The ergonomics of the new Roval Alpinist Cockpit II are a notable step up from the outgoing model. This, together with the new frame and Alpinist CLX II wheels, results in a good ride quality while still retaining the sharpness and communication you’d expect from an S-Works bike. While the featherweight design and responsiveness are still there, it’s the plushness of the ride that feels light-years ahead of its predecessor – even in 28mm trim. This can be ramped up even further with 30 or even 32mm tyres, and will add a little more mass to the system weight, but it is something I highly recommend. I ran the pressures as low as 55psi front and back (at 62kg), but reckon I’d have got away with 50psi if I'd opted for 30mm tyres.

While it’s an absolute joy to ride up hills, it’s equally as rewarding during descending situations. The lower bottom bracket and slightly longer wheelbase have boosted stability, while the improved communication from increased stack and integrated bar allows you to lean into the bike’s front end grip with assurance. Sure, the riding position is a tad more upright than before, but everything still feels dynamic. It’s only when the going gets flat that you may feel the Aethos struggling somewhat – aerodynamics is not its strong point, and in full lightweight trim (and shallow wheels), you’ll need to work harder to keep up with contemporary all-rounders.

Classic in looks and modern in action, the Specialized S-Works Aethos 2 garnered a lot of attention during testing (Image credit: Aaron Borrill)

The Aethos, however, is not about all-out racing or barreling along the flats at 40km/h and above. While it can do all those things, with a system weight of 5.88kg (6kg with pedals), the hills and mountains are its natural habitat, where it will bring the most enjoyment. And then once you crest, the alterations to the geometry will have you scything down the other side like a seasoned pro. It’s a sublimely entertaining bike.

The bike rolls on a pair of Roval Alpinist CLX III wheels shod with 28mm S-Works Turbo TLR Race tyres (Image credit: Richard Butcher)

Value

Specialized has done an incredible job with the new Aethos and created what I feel is pretty damn close to the perfect bike for the general rider. The S-Works Aethos model, in particular, might be a refined, superbly outfitted bike, but at £11,499 / $13,999 / €13,499, it’s just too pricey to justify, let alone recommend, in the current economic climate.

Thankfully, there are other models in the range to choose from, including the Pro (£7,249 / $8,499 / €8,499) and Expert (£5,499 / $6,999 / €6,299), the latter of which comes in around half the price of the Halo S-Works model. While it’s around a kilo heavier at 7.12kg (in size 56cm), it still gets a carbon frame and is outfitted with Shimano Ultegra Di2 and Roval carbon wheels but loses the fully integrated cockpit in favour of a Roval Alpinist carbon bar and alloy stem.

While it might lack the claimed stiffness-to-weight of the S-Works Fact 12r frame, it still possesses the climbing efficiency, balanced geometry and 35mm tyre clearance, making it a worthy alternative if you’re on a budget.

If you've got the cash to burn, however, the S-Works Aethos 2 elevates the experience to the highest level and will leave a massive smile on your dial every time you ride it.