Specialized Aethos Pro Ultegra Di2 Road Bike 2025
The Aethos line promises three things: exceptional light weight, perfectly-balanced ride characteristics, and undeniable style, and this Aethos Pro is no exception. Aethos: Billions of calculations in the pursuit of one thing—the perfect ride.
The Aethos frame has been designed with the perfect combination of ultimate ride feel, light weight, and style. From accelerating up steep pitches and descending technical descents, to all-day saddle comfort on even the longest coffee rides, the Aethos hits the mark. But how, you ask? By reinventing the traditional road shape found on bikes of the past, we’ve subtly altered these shapes to deliver massive gains in stiffness and balance, all without affecting weight or durability. Pair that with an entirely new layup and process that we’ve perfected over multiple decades, and you have the lightest frame out there (585 grams, S-Works, size 56cm). The Aethos is more than just a new bike, it’s the first of a new breed.
A featherweight frame is useless without confidence-inspiring ride characteristics, which is why we’ve developed the Aethos to have the perfect balance of front and rear stiffness combined with exceptional ride quality. By studying the flexing and breathing of carbon fiber, we were able to discover groundbreaking findings about how forces flow through frames. Just a few pedal strokes, and you’ll realize this sublime ride sets a new standard.
Every detail, from the derailleur hangers to the fork expander plug, has been designed with style, weight, and durability in mind. We’ve also spec’d it with Roval’s all-new Alpinist carbon seatpost and wheels, further saving weight and improving ride characteristics. Everything in pursuit of the perfect ride.
Technical Specification
| Frame/Fork | FACT Carbon, 12x100mm thru-axle, flat-mount disc |
| Handlebars | S-Works Short & Shallow, 125mm Drop, 75mm Reach w/Di2 Hole |
| Stem | Specialized Pro SL, alloy, 4-bolt |
| Tape | Supacaz Super Sticky Kush |
| Saddle | Body Geometry Power Pro with Mirror, hollow titanium rails |
| Seatpost | Roval Alpinist Carbon Seatpost |
| Seat Binder | Specialized Alloy, 30mm |
| Front Brake | Shimano Ultegra R8170, hydraulic disc |
| Rear Brake | Shimano Ultegra R8170, hydraulic disc |
| Chain | Shimano M8100, 12-speed w/ quick link |
| Crankset | Shimano Ultegra R8100 with 4iiiis Precision 3+ Power Meter |
| Chainrings | 52/36T |
| Bottom Bracket | Shimano Threaded BSA BB |
| Front Derailleur | Shimano Ultegra Di2 R8150, braze-on |
| Rear Derailleur | Shimano Ultegra Di2 R8150, 12-speed |
| Shift Levers | Shimano Ultegra Di2 R8170, hydraulic disc |
| Cassette | Shimano Ultegra, 12-speed, 11-30t |
| Front Wheel | Roval Alpinist CL II, 21mm internal width carbon rim, 33mm depth, Win Tunnel Engineered, DT for Roval 350 hub, DT Swiss Aerolite spokes, Tubeless Ready |
| Rear Wheel | Roval Alpinist CL II, 21mm internal width carbon rim, 33mm depth, Win Tunnel Engineered, DT for Roval 350 hub, DT Swiss Aerolite spokes, Tubeless Ready |
| Front Tyre | S-works Turbo 2BR, 700x28mm |
| Rear Tyre | S-works Turbo 2BR, 700x28mm |
| Inner Tubes | 700x20-28, 48mm Presta Valve |
Built, Checked, Tuned and Tested
All our bikes are fully built, checked, tuned and tested by our Cytech qualified mechanics and then securely packaged, ready for delivery. All you have to do is add the pedals (if included), attach the handlebars to the stem and tighten them following the included detailed instructions or by watching our video and using the provided FREE tools. Visit our Bike Assembly page to see how you assemble your new bike once you receive it.
All bikes collected from our shop, are built, tested and ready to ride. For hassle-free home delivery and bike set-up from a qualified mechanic use our Premier Delivery Service.
Please note, occasionally, manufacturers may change the specification without notice. Bicycles do not come with pedals unless otherwise specified. Bikes ordered for delivery will not arrive with the pedals installed, please refer to the owners manual and pedal installation guides provided for guidance. We do not install accessories to bikes, including mudguards. Bikes ordered for delivery that have tubeless compatible tyres and rims will arrive with inner tubes installed or with tubeless valves installed, this will be brand dependent. Sealant is available to be purchased separately.
If you require any assistance please contact our Customer Care team.
Specialized Aethos Pro Ultegra Di2 Road Bike 2025 Sizing
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