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Video: Specialized Aethos First Ride Review - How does the world’s lightest disc-brake road bike ride?

We headed to a sunny Solihull for a quick spin on the Specialized Aethos. This hyper-light disc-brake road bike is stunningly quick.

No, you’re not looking at an old Specialized Tarmac with disc brakes, this is the Aethos, a brand new road bike from Specialized that is focused on everything apart from racing. I got my hands on this ultra-light bike, if only for a short ride and here are my thoughts about what this bike brings to the party.

First off, it’s nice to see high-end road bikes being designed without an eye on racing. In the information that Specialized has given us, they state that this bike will not be ridden by the pros in races. They have the SL7 for that which can be built to the UCI’s 6.8kg minimum weight rule.

This is a bike for you and me, the average (well-off) roadie that doesn’t care about marginal aero gains or drag and all of that.

With the Aethos, Specialized is taking things back to when stiffness to weight ratio and handling ruled the roost and I, for one, am rather happy about that. If you want fast, you have the Tarmac SL7 and if you want hyper-fast you still have the Venge, for now. This seems like it could be the general riding dream bike.

That said, Specialized has got UCI approval for the frame, so you can race on yours and take it to the bigger sportives if that’s your thing.

The tube shapes here might look round and they are, mostly. Specialized says that their engineers studied the “flexing and breathing of carbon frames in the pedalling test rig, and they realised the industry’s understanding of how forces flow through a frame was incomplete and ripe for massive improvements. We used staggeringly large supercomputer simulations—more than any humans can do in a lifetime—to subtly alter round tube shapes. This made their shapes more conical in key areas to deliver huge gains in stiffness and balance with the minimum amount of material.”

The headline result of all of that is the weight or lack of it. Specialized says that the lightest build comes in at just 5.8kg. For a disc brake road bike, that is certainly impressive, especially when you consider that this is a pretty standard build. There is nothing here that you’d only find on a hill-climb bike like a silly saddle or parts that require scary torque settings.

Weight is still enemy number one when it comes to getting up hills quickly so we’ll certainly be taking this bike into the hills.

Specialized says that their standard test ride for this bike was the ‘Big Easy’, an 80-mile ride in the Santa Cruz mountains that takes in 7000ft of climbing. On this short ride around Solihull, we weren’t really able to replicate that, but I’ll be ticking off a lot of climbing miles to see if the incredible acceleration that I’ve felt today is replicated when the gradient gets really steep. I’ve got a few hill climbs lined up too.

Specialized is also talking a lot about handling. With no aero tube shapes or need to make the Aethos super low and long, the handling should be free to be nicely balanced. I’ve only ridden 40 short kilometres on this bike so that is something that I’ll have to test properly back on home roads.

Speaking of home roads, I often moan about the road surfaces around the Mendip hills where you’ll often find me riding. It will be interesting to see how the stiffness to weight focus that Specialized has placed on this new bike impacts on the compliance. There really is no point having a super stiff bike if it saps all of your energy by providing a harsh ride.

One thing that will certainly help with comfort is the space for 32mm tyres. This one that I have here comes with 26mm S-Works Turbo Cotton tyres but should you want to maximise comfort then you can fit a 32mm tyre on a rim with an internal width of 21mm and still have 4mm clearance around the tyre.

Other sensible features include a threaded bottom bracket that we have seen a few brands reverting to recently. Pressfit as a system is very good when it works, but the tolerances needed have presented a few brands with quality control issues and to be quite frank, I don’t want to be bothered by creaking while I’m out riding. Silence is golden and I’m happy to see threaded systems coming back.

If the build is sensible then I’m afraid that the price isn’t. The collector’s edition that is limited to just 300 units will set you back a whopping £13,000. This one that I have here is £10,750, or £250 more than the new S-Works SL7. The SRAM RED eTAP AXS build is also £10,750.


The bike that I now have on test doesn’t feature anything revolutionary when you take a look at the spec sheet. You’re getting a Shimano Dura-Ace Di2 groupset along with Roval’s Alpinist wheels, S-Works finishing kit and a 27.2mm Roval Alpinist seatpost. The saddle is a stock S-Works Power, so it’s got scope to get even lighter if you’re looking at this and thinking about hill climbs.

One final note and a feature that I instantly noticed is the subtle paint scheme and branding. I used to love the old style Cannondale Supersix frames when people got custom paint jobs with just a little ‘Cannondale’ just on the top tube. The Aethos channels that clean feeling and I really like it. We can leave the massive logos to the riders that are paid to advertise their bikes.

So I’ll be riding the Aethos now for a month or so then we’ll have a full review on the site. What do you think of the bike? Are you happy that Specialized has made a superbike for riders that aren’t interested in racing? Does this show that high-end road bike design shouldn’t be lead by the needs of the pro peloton? Let us know down in the comments below.

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