2026 Specialized Tarmac SL8 Expert vs 2025 Specialized Aethos Pro
The Specialized Aethos Pro size closest to your 54 is the 54. Compare the 54 instead
What changes on the Specialized Aethos Pro
Compared with the Specialized Tarmac SL8 Expert in 54, the Specialized Aethos Pro in 61 places the top of the head tube 68 mm higher and 24 mm further forward, relative to the bottom bracket. Its wheelbase is 34 mm longer, which can contribute to stability at speed.
- Frame stack
- +68 mm
- Higher front end
- Frame reach
- +24 mm
- Longer frame reach
- Wheelbase
- +34 mm
- Longer: steadier at speed
- Head angle
- +1.0°
- Steeper: sharper steering
- Chainstays
- ±0 mm
- About the same
The two frames
Specialized Tarmac SL8 Expert, 54Specialized Aethos Pro, 61Drawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Tarmac SL8 Expert 54 | Specialized Aethos Pro 61 | Difference |
|---|---|---|---|
| Reach | 384mm | 408mm | +24 mm |
| Stack | 544mm | 612mm | +68 mm |
| Head tube angle | 73° | 74° | +1.0° |
| Seat tube angle | 74° | 73° | −1.0° |
| Effective top tube | 541mm | 595mm | +54 mm |
| Chainstay length | 410mm | 410mm | ±0 mm |
| Wheelbase | 978mm | 1012mm | +34 mm |
| BB drop | 72mm | 72mm | ±0 mm |
| BB height | 268mm | 268mm | ±0 mm |
| Standover | 768mm | 824mm | +56 mm |
| Seat tube length | 473mm | 567mm | +94 mm |
| Fork length | 370mm | 369mm | −1 mm |
| Head tube length | 137mm | 204mm | +67 mm |
Differences are the Specialized Aethos Pro minus the Specialized Tarmac SL8 Expert. Full charts: 2026 Specialized Tarmac SL8 Expert, 2025 Specialized Aethos Pro.
Where each sits in its class
Specialized Tarmac SL8 ExpertSpecialized Aethos Pro
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 Tarmac SL8 ExpertExpert | Specialized Aethos Pro |
|---|---|---|
| Frame | Specialized Tarmac SL8 FACT | not listed |
| Shifter | SRAM Force AXS E1 HRD | not listed |
| Derailleur | SRAM Force AXS E1 | not listed |
| Cassette | SRAM Force XG-1270 | not listed |
| Chain | SRAM Force E1 | not listed |
| Crankset | SRAM Force E1 | not listed |
| Bottom bracket | SRAM DUB | not listed |
| Wheelset | Roval C38 | not listed |
| Tire | Specialized S-Works Turbo | not listed |
| Brake | SRAM Force AXS E1 | not listed |
| Headset | Specialized SL7 | not listed |
| Seatpost | Specialized S-Works Tarmac SL8 | not listed |
| Saddle | Specialized Power Expert | not listed |
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