2025 Specialized Tarmac SL8 Pro vs 2025 Specialized Aethos Pro
The 49 is the Specialized Aethos Pro size closest to your 49 Specialized Tarmac SL8 Pro. 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 Aethos Pro
Compared with the Specialized Tarmac SL8 Pro in 49, the Specialized Aethos Pro 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
- ±0.0°
- About the same head angle
- Chainstays
- ±0 mm
- About the same
The two frames
Specialized Tarmac SL8 Pro, 49Specialized Aethos Pro, 49Drawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Tarmac SL8 Pro 49 | Specialized Aethos Pro 49 | Difference |
|---|---|---|---|
| Reach | 375mm | 375mm | ±0 mm |
| Stack | 514mm | 514mm | ±0 mm |
| Head tube angle | 71.75° | 71.75° | ±0.0° |
| Seat tube angle | 75.5° | 75.5° | ±0.0° |
| Chainstay length | 410mm | 410mm | ±0 mm |
| Wheelbase | 973mm | 973mm | ±0 mm |
| BB drop | 74mm | 74mm | ±0 mm |
| BB height | 266mm | 266mm | ±0 mm |
| Standover | 735mm | 705mm | −30 mm |
| Seat tube length | 445mm | 431mm | −14 mm |
| Fork length | 370mm | 369mm | −1 mm |
| Head tube length | 109mm | 109mm | ±0 mm |
| Effective top tube | not listed | 508mm |
Differences are the Specialized Aethos Pro minus the Specialized Tarmac SL8 Pro. Full charts: 2025 Specialized Tarmac SL8 Pro, 2025 Specialized Aethos Pro.
Where each sits in its class
Specialized Tarmac SL8 ProSpecialized Aethos Pro
Each bike is ranked against the other road bikes on Quiver, on frame geometry alone. Not your hand position or ride feel.
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