The Specialized S-Works Aethos is not an all-road bike. That much should be obvious but it’s included in the Velo All-Road Field Test so it’s worth pointing out.
The Specialized S-Works Aethos is also not a race bike. The Aethos hit the market way back in 2020 as an answer to a question increasingly asked as race bikes get ever more high-tech. What would a classic race bike be if someone transported it to the future? The answer, at least according to Specialized, is to take modern race bike geometry but combine it with ultra-light carbon, round tube shapes, external routing, and traditional bottom brackets and seat post clamps. That’s the Aethos in a sentence.
We included this bike in our round-up as a control to the experiment. It’s still not an actual race bike, more closely aligning to the spirit of an all-road bike, but it’s definitely a go fast bike.
In terms of geometry what that means is an almost exact copy of the Specialized Tarmac SL8. The only real difference is that the top tube of the Aethos drops as it heads away from the front of the bike. There’s an additional 18mm of seatpost showing (in size 52) and that makes for a more comfortable and snappier ride feel.
If you compare the opposite direction to the Specialized Roubaix then you see the real difference in an all-road bike. Sticking to a size 52 the Roubaix has 10mm less reach, 39mm more stack, a degree slacker head tube, a longer chainstay, and a 13mm longer wheelbase. That means the Roubaix is more comfortable and stable. The Aethos is more fun though.
Shockingly, or perhaps because of the age of the frame, the Specialized Aethos is not also the more expensive bike. The S-Works Aethos with a SRAM red build retails for $11,499.99 while the same build level in the Roubaix adds $250 at $12,249.99. If you drop to the same level as our Roubaix test bike that extends even a bit more with the Aethos coming in at $6499.99 or $1,000 less than the Roubaix. That Future shock probably isn’t free to make.
Specs
| Frameset | S-Works Aethos FACT 12r Carbon |
| Drivetrain | SRAM RED AXS |
| Gearing | 48-35T chainrings; 10-33t cassette |
| Handlebar/Stem | S-Works Short & Shallow (carbon/40cm) with Roval Alpinist (alloy/90mm) stem |
| Seatpost | Roval Alpinist Carbon Seatpost |
| Saddle | S-Works Power with Mirror |
| Wheels | Roval Alpinist CLX II |
| Tires (control) | S-works Turbo 2BR, 700x28mm |
| For more: | Specialized website |
What we like about the Specialized S-Works Aethos
The list of pros in this review boiul down to a number of ways of saying the same thing. This bike is about fun and there’s both a simplicity and clarity of purpose that builds from that point of focus.
There are some that will the decisions around this bike, more and more as the model stretches out the time between updates, as a negative. The Specialized S-Works Aethos is not for those people. The bike is not about efficiency or having the right tool for the job. Instead the Aethos is all about riding a bike that feels amazing to ride.
That starts with being lightweight. Now to be clear there’s lightweight and then there’s class leading even after five years lightweight. The Specialized S-Works Aethos is the bike you hand to people to shock them but in my experience it’s even shocking to pick it up after you’ve had it in hand for an extended period of time.
To get that light, Specialized seems to have settled on round tubes. There’s no extra material for corners but those round tubes aren’t just light. They also provide excellent ride feel. You are always engaged with the road and moving the bike under you is exciting.
Those round tubes also keep things rather comfortable. The Specialized S-Works Aethos isn’t the stiffest bike you can buy but that’s a big part of the charm. There’s exposed seatpost and there’s flex where you want it. You won’t find yourself calling the Aethos a noodle but it’s not punishing. It soaks up road noise like an old steel bike with a bit of targeted flex and inherent vibration dampening.
What’s likely to be more controversial than all that is how easy this bike is to live with from a mechanical perspective. Of course no one will complain about an easy to live with bike. Threaded bottom brackets and external seat post binders are obvious wins. The potential issue is that there’s a standard bar and stem with external routing. Just understand that you can’t have easy to live with without exposed cables.
What we don’t like
Or maybe you can. The two most obvious issues with the Specialized S-Works Aethos boil down to the design showing its age. There are solutions that make a bike easier to live with and hide the cables. Look uses a two piece bar and stem on the Look 795 Blade RS or there are a number of ways to route under the stem for a kind of hybrid external routing. If the Aethos came to market in 2025 it would likely use one of these strategies.
The same is true of the tire clearance. You could argue that a max of 32 mm is fine on a race-ish bike like the Aethos but it’s also outdated. Modern race bikes, even aero bikes, tend to have space for 34mm and the Specialized S-Works Aethos doesn’t reflect that because it’s older.
Aside from those details of design age, there’s also the handling. This is more of a love it or hate decision though. If you are buying the Aethos you have to understand it’s not an all-road bike. The handling is sharp. On descents it goes exactly where you point it without needing to lean and cajole it. Steer where you want but that’s a double edged sword and the handling is also twitchy. The lightweight nature of the Aethos doesn’t help here and this bike doesn’t especially love to even follow a white line with ease. Expect to be on your guard a little.
Livability
Much of this section is covered in both what we like and what we don’t. The whole game here is that this is a throwback to an earlier time. The bottom bracket is a BSA piece that means not only is it threaded but there’s tons of room for the tool to grab the BB. There’s also a simple external seat post binder and cables are external as well. If you like to tinker with a bike. This is an easy one.
Who is the bike for?
This bike is for everyone who wants an engaging and fun ride but isn’t looking for marginal gains. The Specialized S-Works Aethos is light almost as a byproduct of the ride feel and there’s definitely aero gains you won’t get. If you want the fastest bike and the perfect tool for specific jobs then look elsewhere. If you want a bike that feels classic and fast then the Specialized S-Works Aethos is the bike for you.