New Specialized Aethos 2 review: The bike it should have been all along, but not everyone will be happy

Specialized has today launched the latest version of its featherweight road bike, the Aethos, with the aptly named Aethos 2.

The American brand has given it a host of subtle-but-significant updates, including a taller head tube and a more relaxed geometry, a longer wheelbase and lower bottom bracket, bigger tyre clearance, and internally routed cables for a clean look.

Given the Aethos has never been focused on racing, you could argue that it's now the bike that the Aethos should have been all along, but many people will be put off by the changes Specialized has implemented.

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Ahead of today's launch, I got to ride the S-Works Aethos 2 with Dura-Ace, which, according to the brand, tips the scales at a smidge over 6kg, to see whether any of the old bike's magic has been lost, or whether the changes retain that special je ne sais quoi, while opening up the Aethos platform to a wider audience.

But first, to try and unpack what that magic is, let's take a step back in time.

At its launch in 2020, the original Specialized Aethos was arguably the only bike of its kind; a lightweight road bike that didn't concern itself with being UCI legal or being used in races.

It laughed at the 6.8kg minimum weight limit, it shunned racing intentions, and all the effort that usually goes into aerodynamics was instead placed on chasing a feathery weight. Not to mention the floaty ride characteristics (and, probably, the customers) that were lost when the Tarmac SL6 merged with the Venge to become the SL7.

The result was a top-tier bike that tipped the scales at bang on 6kg (Well, 5.9kg if you were one of the 300 buyers of the $14.5k 'Founders Edition'). It boasted a frame weight of just 585g, rode like silk, and became a very popular bike among everyone from the non-competitive fast kids to the more sedate Sunday-café-ride crowd. It was especially unique in targeting non-racers with a racy geometry, and while this made it especially fun to ride, it probably put a lot of riders off.

Since then, other brands have followed suit to a degree, but none have spun the same anti-race-bike yarn. The Cervélo R5 and Scott Addict RC Ultimate are two that have launched in the past 12 months alone, and Factor's O2 Vam before it, but all three have made appearances at the Tour de France.

What's new

Fast forward back to today, and the S-Works Aethos 2 frame is heavier than its forebear (595g vs 585g for an unpainted 56cm), but thanks to new Roval Alpinist CLX III wheels that launched earlier this week complete with composite spokes, and a new Roval Alpinist cockpit, not to mention a new lighter Red groupset from SRAM, the lightest available build (previous Founder's Edition aside) is now marginally lighter than before, with the top-tier Red AXS model tipping the scales at 5.97kg.

There's no 'Founder's Edition' that we know of this time round, at least at the time of launch.

Those are the headline claims, and Specilaized has wheeled out the same 'so light it's a crime' and 'break the rules' taglines, but the geometry changes are arguably more important.

Across the size run, Specialized says an average of 15mm has been added to the head tube length, although by our comparison of the geometry charts, the true average is 11mm.

In turn, the stack height has grown. In fact, it's grown by 15mm on all sizes from 54 to 61, and the 49cm and 52cm frames have smaller increases of 8 and 11mm, respectively.

The rake of the three (size-specific) forks has been adjusted to maintain a similar trail, and thus similar handling, as before.

This does assume you run the same tyre size, though. The new bike is specced with the same size 28mm as before, but can now handle up to 35mm, which would increase the trail and slow the handling down a little.

The wheelbase has been lengthened too, likely adding high-speed stability.

Even though the majority of this extra wheelbase has come from the front half of the bike (the chainstay length remains unchanged), the added stack and slacker head tube (avg 0.46° across sizes) mean reach is slightly shorter than before, too.

But does this geometry change make the Aethos the bike it should have been all along? Is it still fun, but more relaxed and designed for the type of rider that cares little for speed and aggressive positions? Or does it quieten the bike's exciting ride quality in favour of sedate, safe, and boring?

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First ride impressions

Depending on your bike fit preferences, the new geometry will result in one of three outcomes:

1. If you'd have run the previous bike slammed (or close to it), you'll be forced into a higher position here.
2. If the previous bike was too aggressive for you, this change might open the Aethos up to you as an option where previously it would have been uncomfortable.
3. If you were somewhere in the middle, you'll just have to reduce the number of spacers you need to run, probably need to cut the steerer shorter and lose a bit of resale value, but your bike will look a bit more 'pro' for it.

I am predominantly in that first category, but as I get older and slower, I'll concede I'm not averse to a few extra millimetres of stack and I'm edging more towards category three.

As a result, I'm not seeing the changes as a bad thing, especially on a bike like this, which invites you to look around at the view more than stare at your head unit, counting the watts. I'm sure others will disagree, though.

That's not my way of saying the bike is boring, though. Lightweight bikes are, in most cases, more exciting to ride than heavier hyper-aero steamrollers, and Specialized's road bikes are regularly among the most agile and 'fun' to ride.

Contrary to the Factor O2 VAM, which took a while for me to build confidence in its handling, here I found myself flicking the bike around almost immediately, hopping onto kerbs, zigzagging unnecessarily around road markings, and weaving tightly around potholes instead of just bypassing them. It has a strong sense of the S-Works Crux about it, which is a fun and flickable lightweight gravel bike.

But to be honest, I found myself longing to be on the Crux instead, so I could nip off into the trails and make the most of that snappy, fun handling, not least given that the Box Hill ascent we climbed is surrounded by trails.

I'd be lying if I said I wasn't still having a great time, though. The Aethos's lighter and tighter geometry brings some of that fun to the road, even if roads are comparatively devoid of fun things to swerve around and hop over. Potholes are about as good as you'll get in that regard.

Speaking of potholes, that leads me to my biggest complaint about the Aethos 2, though, and that's how Specialized has chosen to spec it.

Firstly, even though it has been given clearance for 35mm tyres, it ships with 28s, so despite the buttery ride quality offered by the frame, the imperfect roads in the Surrey Hills were still quite noticeable and clattering.

For some reason, my test bike was specced with 44cm bars, matching the spec on the original Aethos, but the geometry charts supplied by the brand suggest this is an anomaly. Specialized says all but the size 49cm will be sized down by 20mm.

I applaud this move, but don't think it goes far enough. I'd prefer to be given the choice. Given that the Aethos 2 comes with a one-piece cockpit worth £575, and integrated cabling, the time and cost involved with swapping is even higher than before - not that it should be acceptable at any price.

Those complaints aside, where any lightweight bike should shine is when riding up hill, and at 6kg, it'll be no surprise to hear the Aethos 2 does that very well.

With that said, given fitness levels continually change, and this summer has been a particularly bad one for mine. I've no doubt it's as good as ever, but my comparison of how the Aethos 2 responds under power versus its predecessor (which I last rode two years ago) is pretty meaningless.

Similarly, the outgoing model was a very capable descender, and the new model felt similarly comfortable at speed, but testing Aethos 2 on unfamiliar roads isn't exactly empirical. I felt unwilling to really let loose on twistier descents, but the fast straight ones were great fun; enough for a Strava PR on one that I've ridden a few times before, and more than enough to reassure me that the geometry changes haven't muted the bike's stable-at-speed abilities.

Pricing, specs, and value

With the Aethos 2, Specialized has narrowed its focus on the premium end of the market, so there's no longer a Comp or Sport model available.

The range tops out at the S-Works model, as ever, but below this, only the Expert and Pro models exist. Both of which use Fact 10R carbon fibre and have frame weights of 705g (56cm unpainted).

Interestingly, there's no model below SRAM Force AXS / Shimano Ultegra Di2 spec.

At £7,249.00 ($8,499.00 / €8,499.00), the Pro model gets a choice of SRAM Force AXS or Shimano Ultegra Di2. Both of these get the older Alpinist II wheels and the new Alpinist II cockpit, plus a Power Pro Mirror saddle and S-Works Turbo TLR Race tyres.

The Expert model, priced at £5,499.00 ($6,999.00 / €6,299.00), is specced with Ultegra Di2, Roval's C38 wheels, S-Works Turbo tyres, the Power Expert saddle, and Roval's older Alpinist cockpit.

At £11,499.00 ($13,999 / €13,499), the top-tier S-Works model gets a choice of SRAM Red or Shimano Dura-Ace Di2, with the latest Alpinist III wheels, Specialized Turbo TLR Race tyres, an Alpinist II cockpit and the S-Works Power w/Mirror saddle.

To pass judgment on whether that offers good value is a tough ask after just one ride, but if we compare it against the two other sub-6kg bikes mentioned above from Cervélo and Scott, the Aethos is technically the cheapest, albeit by just £1 in the UK.

If you're happy with the 28mm tyres and the handlebar width you get off the shelf, then it's much of a muchness against the Cervélo R5, priced at £11,500.00 (with narrower bars, but 26mm tyres).

The Scott Addict RC Ultimate, however, is £1,200 more at £12,799.00, making it the outlier.

Early verdict

The updates that Specialized has made to the Aethos will likely put some riders off, and with no significant weight saving to be had, existing Aethos owners should probably just stick with what they have, unless integrated cable routing is enough to sway you.

The majority of the weight saving comes from the wheels, and indeed some of the ride quality improvements come as a result of Specialized's new thermoplastic 'composite' spoke technology, which goes against the usual 'carbon spokes are stiff' storyline.

With that said, the new bike offers a more relaxed position, longer wheelbase and lower bottom bracket, meaning given it's not trying to be a race bike, it will likely open it up to more people.

But when asked if I'd buy it, my answer is a pretty immediate no.

The forced inclusion of a 42cm handlebar is an immediate turn-off for me. I know some bike shops will make the switch for their customers prior to the handover, but it's at their discretion and one I'd like to see baked into the Specialized purchase journey from the off.

I also find the decision to spec 28mm tyres odd, and would prefer to see fast-rolling 32 or 35mm tyres specced from the factory. That's what this bike is crying out for, even if it does increase the weight and make it look less impressive on paper and sell sheets.

But even if Specialized fixed those problems, I'd still buy the Crux instead, because it's got all the same credentials as this, and a whole lot more. If I were buying an Aethos 2, it would be because I don't care about how fast I'm going to go. I'd be buying it for that fun ride quality and the quick, flickable handling.

On the road, I can have as much fun on the Crux, but with the added ability to nip into the trail centre and have even more.

The Aethos 2 will be a great bike for a lot of people, just not for me.