2025 Specialized Aethos FACT 12r Carbon vs 2026 Specialized Tarmac SL8 Pro Shimano
The 49 is the Specialized Tarmac SL8 Pro Shimano size closest to your 49 Specialized Aethos FACT 12r Carbon. We match frame stack and reach. This is a geometry comparison, not a fit recommendation; stem, spacers, handlebars and saddle setup also affect your riding position.
What changes on the Specialized Tarmac SL8 Pro Shimano
Compared with the Specialized Aethos FACT 12r Carbon in 49, the Specialized Tarmac SL8 Pro Shimano in 49 places the top of the head tube at about the same height and about as far forward, relative to the bottom bracket.
- Frame stack
- ±0 mm
- About the same height
- Frame reach
- ±0 mm
- About the same reach
- Wheelbase
- ±0 mm
- About the same
- Head angle
- n/a
- One of the bikes has no number for this
- Chainstays
- ±0 mm
- About the same
The two frames
Only the Specialized Aethos FACT 12r Carbon is drawn. The Specialized Tarmac SL8 Pro Shimano numbers we have for size 49 are missing the head angle.
Geometry side by side
| Measurement | Specialized Aethos FACT 12r Carbon 49 | Specialized Tarmac SL8 Pro Shimano 49 | Difference |
|---|---|---|---|
| Reach | 375mm | 375 | ±0 mm |
| Stack | 514mm | 514 | ±0 mm |
| Head tube angle | 71.75° | not listed | |
| Seat tube angle | 75.5° | 75.5 | ±0.0° |
| Effective top tube | 508mm | not listed | |
| Chainstay length | 410mm | 410 | ±0 mm |
| Wheelbase | 973mm | 973 | ±0 mm |
| BB drop | 74mm | not listed | |
| BB height | 266mm | not listed | |
| Standover | 705mm | not listed | |
| Seat tube length | 431mm | not listed | |
| Fork length | 369mm | not listed | |
| Head tube length | 109mm | 109 | ±0 mm |
Differences are the Specialized Tarmac SL8 Pro Shimano minus the Specialized Aethos FACT 12r Carbon. Full charts: 2025 Specialized Aethos FACT 12r Carbon, 2026 Specialized Tarmac SL8 Pro Shimano.
Where each sits in its class
Specialized Aethos FACT 12r CarbonSpecialized Tarmac SL8 Pro Shimano
Each bike is ranked against the other road bikes on Quiver, on frame geometry alone. Not your hand position or ride feel.
What each ships with
The stock build of each bike's first listed trim. Parts that match are dimmed.
| Part | Specialized Aethos FACT 12r CarbonS-Works FACT 12r Carbon | Specialized Tarmac SL8 Pro ShimanoPro - Shimano Ultegra Di2 |
|---|---|---|
| Frame | Specialized S-Works Aethos FACT | Specialized Tarmac SL8 |
| Seatpost | Roval Alpinist | Specialized S-Works Tarmac SL8 |
| Fork | not listed | Specialized FACT 10r |
| Shifter | not listed | Shimano Ultegra R8170 |
| Derailleur | not listed | Shimano Ultegra R8150 Di2 |
| Cassette | not listed | Shimano Ultegra |
| Chain | not listed | Shimano XT M8100 |
| Crankset | not listed | Shimano Ultegra R81000 |
| Bottom bracket | not listed | Shimano Threaded BSA |
| Wheelset | not listed | Roval Rapide CL III |
| Tire | not listed | Specialized S-Works Turbo |
| Brake | not listed | Shimano Ultegra R8170 |
| Rotor | not listed | Shimano Ultegra R8170 |
| Handlebar | not listed | Roval Rapide Cockpit |
| Stem | not listed | Roval Rapide Cockpit |
| Bar tape | not listed | Supacaz Super Sticky Kush |
| Saddle | not listed | Specialized Power Pro |
Know what is on every bike.
Add your bike to Quiver. Keep its parts, setup, and service history together, then share your build.
Explore the app
