Specialized S-works Aethos
Super light and super fun
Super light and super fun
When Peter Denk described his process for exploring bike-frame behaviour, it had an air of mysticism about it. In September, I was on a video call with the engineer from Specialized as well as others from the Morgan Hill, Calif.-based company. They took me through the creation and features of their new bike, the Aethos. Its development started roughly four years ago, after the launch of the Tarmac sl6. Denk put that frame on a pedalling machine. “I was staring for about one hour, almost like a mediation,” he said. “I put my hands on the frame to feel how every tube is distorted and how it deflects. I tried to visualize how the forces flowed through the frame.” This bike reiki led Denk to an epiphany.
Usually a carbon-fibre frame is built with a beefy BB and down tube because, the thinking goes, that’s where the most wasteful flexing occurs. Yet, Denk saw more deflection coming from the head tube than at the bottom bracket. So, he and his team, and a bunch of computers, eventually came up with the tube shapes that you see on the Aethos: a barrel-shape head tube, and top and down tubes that have wider diameters at the front of the bike and taper toward the back. In the end, the frame looks slightly more traditional (apart from its sloping top tube) than most carbon-fibre frames.
The Aethos’s frame is wicked light. A size 54 frame built with the company’s top-end fact 12r carbonfibre mix is 575 g. The Shimano Dura-ace Di2 model that I later tested weighed 6.19 kg on my scale. I don’t have weight-weenie tendencies, but there is something so lovely about a feathery bike. It just saunters up climbs. The bike’s geometry is the same as the latest Tarmac sl7 and old Venge. It’s a formula that Specialized really believes in. And why not? The Aethos is lively and takes corners well at speed.
Curiously, the Aethos is not meant for racing, even though it has a uci-approved sticker on it. Specialized says the Tarmac is for professional competition. The Aethos is just for riding, jamming with friends and having fun. It’s quite a serious machine – power meter, light Roval Alpinist clx wheels, highend carbon fibre – so it doesn’t really seem made for rides that are just for laughs. I think that mismatch between the high-performance spec (and its price) and the marketing of the bike led to above-average cynicism (so I thought) on social media at the bike’s launch in early October. Yes you can have tons of fun on other bikes not meant for racing. Yes the Aethos is expensive. But, it is fast, light and agile. You can’t argue with those features; they are fun.
What isn’t fun is a short testing time frame with a cool bike. I didn’t have as long as I would have liked with the Aethos. I put some good miles on it, but I wasn’t able to swap the 26c tires for treads closer to the maximum 32c width. Would the stiff and light Aethos be as much fun on rough roads as it is on smooth ones? My guess is yes.