2026 Specialized Tarmac SL8 LTD Lucas Beaufort 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 LTD Lucas Beaufort in 54, the Specialized Aethos Pro in 56 places the top of the head tube 21 mm higher and 11 mm further forward, relative to the bottom bracket. Its wheelbase is 13 mm longer, which can contribute to stability at speed.
- Frame stack
- +21 mm
- Higher front end
- Frame reach
- +11 mm
- Longer frame reach
- Wheelbase
- +13 mm
- Longer: steadier at speed
- Head angle
- +0.5°
- Steeper: sharper steering
- Chainstays
- ±0 mm
- About the same
The two frames
Specialized Tarmac SL8 LTD Lucas Beaufort, 54Specialized Aethos Pro, 56Drawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Tarmac SL8 LTD Lucas Beaufort 54 | Specialized Aethos Pro 56 | Difference |
|---|---|---|---|
| Reach | 384mm | 395mm | +11 mm |
| Stack | 544mm | 565mm | +21 mm |
| Head tube angle | 73° | 73.5° | +0.5° |
| Seat tube angle | 74° | 73.5° | −0.5° |
| Effective top tube | 541mm | 562mm | +21 mm |
| Chainstay length | 410mm | 410mm | ±0 mm |
| Wheelbase | 978mm | 991mm | +13 mm |
| BB drop | 72mm | 72mm | ±0 mm |
| BB height | 268mm | 268mm | ±0 mm |
| Standover | 768mm | 769mm | +1 mm |
| Seat tube length | 473mm | 504mm | +31 mm |
| Fork length | 370mm | 369mm | −1 mm |
| Head tube length | 137mm | 157mm | +20 mm |
Differences are the Specialized Aethos Pro minus the Specialized Tarmac SL8 LTD Lucas Beaufort. Full charts: 2026 Specialized Tarmac SL8 LTD Lucas Beaufort, 2025 Specialized Aethos Pro.
Where each sits in its class
Specialized Tarmac SL8 LTD Lucas BeaufortSpecialized 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 LTD Lucas BeaufortS-Works LTD Lucas Beaufort | Specialized Aethos Pro |
|---|---|---|
| Frame | Specialized S-Works Tarmac SL8 FACT | not listed |
| Headset | Specialized SL7 | not listed |
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