The Specialized Aethos 2 refines the brand's ultra-lightweight, ride-feel-focused road platform. Moving away from the aggressive posture of pure race bikes, this second generation shifts toward a performance endurance identity. It is designed for climbers, long-distance riders, and traditionalists who prioritize tactile ride quality and classic round-tube aesthetics over aerodynamic efficiency.
While the original Aethos established a reputation for extreme lightness, this update modernizes the frame with fully hidden cable routing, a universal derailleur hanger, and expanded tire clearance up to 35mm. These additions slightly increase the frame weight, but Specialized offsets this with updated carbon layups and lighter components to keep complete bike weights exceptionally low. The result is a modernized climbing bike that broadens its appeal for everyday riding without losing the lively character that defined the original.
Where to get it.
4 retailers · size 54.
Spec sheet.
Every component shipped with this build.
Geometry & fit.
6 sizes published.
The Aethos 2 introduces a significant geometry shift, moving away from the aggressive, Tarmac-inspired fit of its predecessor. Specialized increased the stack height across the size range, paired with a slightly slacker head tube angle, a longer wheelbase, and a lower bottom bracket. This creates a more upright riding posture that reduces strain on the neck and back during long days in the saddle.
These dimensional changes directly influence the bike's handling. The lengthened footprint and lowered center of gravity improve high-speed stability and cornering composure, taming the twitchy descending characteristics of the first generation. While riders accustomed to slammed, aerodynamic positions might find the front end tall, the relaxed fit accommodates a broader range of cyclists without requiring excessive headset spacers.
Contact points further shape the fit. The new Roval Alpinist Cockpit II, featured on upper-tier builds, uses ovalized tops to distribute pressure across the hands. Crucially, Specialized now offers this integrated bar and stem in thirteen sizes, allowing riders to dial in their reach and width much more effectively than with previous integrated systems.
Where the handlebar sits relative to the bottom bracket — the single most important fit pair.
01Fit geometry6 values
02Component geometry6 values
03Handling geometry9 values
Which size should I buy?
Slide your height to see the recommended size. GearWise's fit algorithm works from the published stack, reach, and ETT — the brand's own recommendation may differ.
→Calculated from GearWise's own stack / reach / ETT algorithm — the brand's size chart may recommend a different size, and a proper bike fit beats any calculator.
The lineup.
6 builds, ranging $6,600 – $14,000.
The Aethos 2 lineup spans three tiers, all utilizing electronic drivetrains, threaded BSA bottom brackets, and the SRAM UDH standard. The flagship S-Works models feature the lightest FACT 12r carbon frame, CeramicSpeed headset bearings, and dual-sided power meters paired with either Shimano Dura-Ace Di2 or SRAM RED AXS. These top builds also introduce the Roval Alpinist CLX III wheels, which utilize lightweight composite spokes to drop rotational weight.
The Pro tier shifts to a slightly heavier FACT 10r carbon frame. These builds use Shimano Ultegra Di2 or SRAM Force AXS, both including power meters. They retain the integrated Alpinist Cockpit II but step down to Roval Alpinist CL II wheels with standard steel spokes.
The entry-level Expert models share the FACT 10r frame and drivetrain options of the Pro tier but omit the power meters. To reduce costs, the Expert builds use a traditional two-piece alloy stem and carbon handlebar, alongside shallower Roval C38 carbon wheels. Across all price points, the bikes ship with 28mm Specialized Turbo tires, leaving the frame's 35mm clearance available for riders who want to upgrade to higher-volume rubber.
From the press.
9 reviews from the cycling press.
Reviewers consistently praise the Aethos 2 for its exceptional ride quality, noting that it climbs with remarkable ease and accelerates eagerly. The frame's low weight and refined carbon layup translate to a highly responsive experience on steep gradients. On the road, testers found the bike "positively addictive during the small surges" (Velo) that happen in group rides.
While the original model was sometimes criticized for feeling nervous on fast descents, the revised geometry has largely remedied this. The longer wheelbase and lower bottom bracket help the bike track smoothly, with one tester noting it was "never unruly and never flapped once" (Cycling Weekly) on poor surfaces. Another reviewer highlighted that the bike "responds eagerly to pedal inputs" (Cyclist Magazine) whether seated or climbing out of the saddle.
The primary tradeoff is aerodynamic efficiency. Without deep tube shapes, the Aethos 2 requires more effort to maintain high speeds on flat terrain or in headwinds compared to dedicated aero bikes. Additionally, multiple reviewers expressed frustration with the stock 28mm tires. Despite the frame's generous clearance, testers felt the narrow rubber transmitted unnecessary road chatter, suggesting that upgrading to wider tires is essential to fully realize the frame's comfort potential.
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