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This 14-Pound Specialized Aethos Has a Wild 1x Drivetrain

I love 1x road bikes and my jaw dropped when this beautiful 1x Specialized Aethos Sagan Collection bike with a massive 10-52t Garbaruk cassette came in UNDER 14 pounds! This might be one of the hottest 1x road bikes I've seen. What do you think?

Written by: Bruce Lin

Published on:

Posted in:Bikes

Regular readers may know I’m a big fan of two things: 1x road bikes and the Specialized Aethos

1x road bikes aren’t the pariahs they used to be. Even Primoz Roglic and Jonas Vingegaard, two of the best racers in the world, rode 1x setups on their way to winning the 2023 Giro d’Italia and Tour de France. 

As for the Aethos, I’ve wanted it ever since it was released in 2020. I’ve always been a bit of a weight-weenie, so of course I'd fall in love with the lightest disc road frame made. The fact that it had no weird proprietary parts or crazy cable routing just made me even more enamored. 

1x Specialized Aethos

My personal 1x Aethos. 16 lbs 2 oz with pedals, cages, and Garmin mount. 

Last year, I finally saved up enough to build my own 1x Aethos. I LOVE my bike, and I’m super proud of the build I put together. But there’s always someone out there who can do it better. 

That’s how I felt when I saw this Sagan Collection 1x Aethos come through TPC. Not only does it look amazing, but when I weighed it, I was stunned to see that it was only 13 lbs 10 oz (6.18 kg - w/o pedals or cages). Of course, I had to drag it into the studio to take a closer look at this impressive and unique build. 

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The Sagan Collection “Disruption” Aethos Frame

Peter Sagan Specialized Aethos DisruptionIf you’re a cycling fan, Peter Sagan likely needs no introduction. But in case you need a refresher, he’s a contender for the best racer of the last decade. He’s won 3 consecutive road world championships, 12 Tour de France stages, the Green Points Jersey a record 7 times, as well as the Tour of Flanders and Paris-Roubaix. 

For years, Sagan has been the face of Specialized road bikes, and Specialized has released several limited edition Sagan frames where he has provided input on the paint. This 2022 Aethos is part of the “Sagan Collection: Disruption,” which launched on the eve of the 2021 Tour de France. 

Sagan disruption 70s colorsSagan in the Disruption Collection release photo. This cream-colored '70s suit and car served as inspiration... I guess? Photo: Specialized

In the past, Sagan has picked metallic gold, rainbow chrome, and full-on glitter, but the Disruption collection is a bit more toned down. Supposedly, Sagan and the Specialized designers looked at the riders who "made waves in the ’70s," specifically rouleurs who were “disruptive enough to break the status quo.” Does that sound a bit like Sagan in the 2010s? That might have been the idea. 

The theme is a bit esoteric, but damn, the frame does look good. Even though it’s not as loud and brash as previous Sagan frames, it still easily caught my eye from across the TPC warehouse. The creamy white color is called ​​”74 Casablanca” while the reddish brown accents are “Ginko.” Hopefully, we were able to capture its beauty in the studio but trust me when I say this frame looks stunning in person. 

Sagan Disruption collectionThe Sagan Collection also features special helmets and shoes. Photos: Specialized

One thing that’s super cool is this bike's sub-14-pound weight was achieved without using the high-end S-Works frame. The S-works frame is 588 grams while the standard version seen here is 699 grams, which is a small difference, but when you’re getting into weights below the UCI limit (14.99 lbs / 6.8 kg) every gram matters. A lot of the weight savings come down to the thoughtful build. 

Note: Once you add pedals (~12-13 oz) and bottle cages the complete bike will be a little over 14 pounds. 

The Massive, but Lightweight Garbaruk 10-52t Cassette

Specialized Aethos 1x drivetrainOne of the major concerns riders have with 1x road bikes is gear range. That's less of a concern with a massive 10-52t mountain bike cassette. The previous owner clearly wanted some seriously low gears. 

While this Aethos uses SRAM's wireless AXS shifters and rear derailleur, it doesn't use a SRAM Eagle cassette. It’s a 12-speed cassette made by Garbaruk, a Polish company that specializes in machining lightweight drivetrain components. (You might be familiar with them if you follow Dangerholm’s absurdly light bike builds.) Like SRAM’s X01 and XX1 Eagle cassettes, The top 11 gears are machined out of a single piece of steel to save weight and maximize rigidity, and they are pinned to an aluminum 12th cog. 

Garbaruk 12 speed XD cassetteSRAM’s top-end Eagle cassettes are already super light, so at 357 grams, the Garbaruk cassette actually doesn’t save weight over an X01/XX1 cassette. But it’s able to match the weight of SRAM’s cassettes for around $100-200 less. You also have several anodized color options for the big cog. 

One feature I like about Garbaruk’s 10-52t cassette is that the second-largest cog is a 44t instead of a 42t like SRAM uses, which makes the final step to the 52t big cog smaller and less jarring. SRAM made a similar change to its cassettes with the latest T-Type Transmission drivetrains, but Garbaruk was ahead of the curve in this case!

The Garbaruk Force AXS Cage + Pulley Kit

Garbaruk cage + pulley kitPhoto: Garbaruk

To work with this massive cassette, the Force AXS derailleur had to be modified using Garbaruk’s SRAM Force Cage + Pulley kit. The machined aluminum pulley cage is longer to handle the increased chain length needed for the larger cassette, and it also repositions the upper pulley so it’s closer to the small cassette cog and farther away from the largest cog. 

This allows a standard Force AXS derailleur, which is designed for a 10-33t cassette, to run smoothly on a much larger 10-52T cassette. A longer pulley cage alone isn’t enough though, so Garbaruk also includes an extender link for the rear derailleur hanger. This allows the derailleur to mount lower, giving it the ability to reach the larger cassette cogs. 

Garbaruk oversized pulley wheelsTo cap it all off, the kit comes with oversized derailleur pulleys. Larger pulleys marginally increase drivetrain efficiency (usually only 1-2 watts) by reducing the amount the chain has to articulate over the pulley wheels. The biggest benefit, however, is that they look badass, especially when they’re anodized. 

Overall, I was pretty impressed with how well this whole system shifts. I do think the SRAM XPLR derailleur and cassette on my own build feels a bit crisper, but the Garbaruk setup was fast, reliable, and easy to live with. 

The Secret to Sub-14: Lightweight Carbon Components

How do you compliment a lightweight carbon frame? With lightweight carbon parts, of course. The two big places to save additional weight are with cranks and wheels. 

The crankset is an e*Thirteen XCX Race carbon gravel crank. At 400 grams with the chainring (and 355 grams without), it is one of the lightest cranksets on the market. To get lighter, you’d have to get a much crazier option, like a THM Clavicula, which costs about 3 times more. 

Hunt 32 Aerodynamicist Carbon wheelsThe HUNT 32 Aerodynamicist Carbon wheels weigh in at an impressive 1,213 grams. This is where the biggest weight savings are. To achieve this low weight, the 32 Aerodynamicist uses shallow hookless carbon rims paired with UD carbon spokes.

At 2.7 grams per spoke, carbon spokes are lighter than traditional steel spokes, while also increasing lateral stiffness. I generally wouldn’t trust 1,200 gram wheels under my 185 pound self, but when hammering back and forth on the TPC test track, the wheels felt sturdy and FAST. 

The hubs have lightweight (98 gram) Galfer Road Wave rotors installed. These rotors have generous cutouts to shed weight. Paired with the wavy shape, these cutouts also enhance cooling by ensuring every part of the brake pad surfaces get exposed to air at some point when the rotor is spinning. 

Roval Alpinist SL cockpitThe Aethos comes from the factory with a lightweight 136-gram Roval Alpinist carbon seatpost. The previous owner decided to match it with a Roval Alpinist SL integrated bar and stem, which comes in at around 255 grams.

Integrated carbon cockpits like this save a lot of weight by removing hardware and clamps. For reference, an S-Works Carbon bar and S-Works alloy stem combo will weigh around 50-65 grams more.  

Who’s This Bike For?

Specialized Aethos lightweight 1x buildThis Aethos is clearly made for one thing: conquering the hardest climbs. With the extremely lightweight build and exceptionally low gearing, it will flatten the steepest grades. I can think of a few climbs here in Colorado where this bike would be very advantageous. 

Would I change anything? If this were my bike, I’d probably swap to a bigger chainring. The small 40t chainring currently installed would feel blissful on 20% grades, but in a fast group ride on the flats, there’s a good chance you’d spin out. I currently use a 46t chainring on my own 1x Aethos. The 46x10t top gear gives me just enough to hang on for dear life when a strong group is hammering along at 30-32 mph.  

Hunt Carbon wheelsIf I could steal one part off this build for my own bike, it'd probably be the wheels. Shedding rotating weight makes the most noticeable difference on how a bike performs, and these HUNT 32 Aerodynamicist Carbon wheels are a good 300 grams lighter than my current wheelset. 

I never had the chance to do any covert parts swapping though, because this bike sold pretty much the same day it was listed. Whether it was the beautiful paint, the blingy drivetrain, or the crazy low weight, it clearly struck a chord with someone. I’m just glad that there are more like-minded 1x road bike lovers out there! 

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