2023 Specialized Aethos Pro vs 2025 Specialized Tarmac SL8 Expert
The Specialized Tarmac SL8 Expert size closest to your 54 is the 54. Compare the 54 instead
What changes on the Specialized Tarmac SL8 Expert
Compared with the Specialized Aethos Pro in 54, the Specialized Tarmac SL8 Expert in 58 places the top of the head tube 47 mm higher and 18 mm further forward, relative to the bottom bracket. Its wheelbase is 28 mm longer, which can contribute to stability at speed.
- Frame stack
- +47 mm
- Higher front end
- Frame reach
- +18 mm
- Longer frame reach
- Wheelbase
- +28 mm
- Longer: steadier at speed
- Head angle
- +0.5°
- Steeper: sharper steering
- Chainstays
- ±0 mm
- About the same
The two frames
Specialized Aethos Pro, 54Specialized Tarmac SL8 Expert, 58Drawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Aethos Pro 54 | Specialized Tarmac SL8 Expert 58 | Difference |
|---|---|---|---|
| Reach | 384mm | 402 | +18 mm |
| Stack | 544mm | 591 | +47 mm |
| Head tube angle | 73° | 73.5 | +0.5° |
| Seat tube angle | 74° | 73.5 | −0.5° |
| Chainstay length | 410mm | 410 | ±0 mm |
| Wheelbase | 978mm | 1006 | +28 mm |
| BB drop | 72mm | 72 | ±0 mm |
| BB height | 268mm | 268 | ±0 mm |
| Standover | 748mm | 808 | +60 mm |
| Seat tube length | 481mm | 515 | +34 mm |
| Fork length | 369mm | 370 | +1 mm |
| Head tube length | 137mm | 184 | +47 mm |
Differences are the Specialized Tarmac SL8 Expert minus the Specialized Aethos Pro. Full charts: 2023 Specialized Aethos Pro, 2025 Specialized Tarmac SL8 Expert.
Where each sits in its class
Specialized Aethos ProSpecialized Tarmac SL8 Expert
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 ProPro | Specialized Tarmac SL8 ExpertExpert |
|---|---|---|
| Frame | Specialized Aethos FACT | Specialized Tarmac SL8 FACT |
| Shifter | Shimano Ultegra R8170 Di2 | Shimano Ultegra R8170 Di2 |
| Derailleur | Shimano Ultegra R8150 Di2, Shimano Ultegra R8150 | Shimano Ultegra R8150 Di2, Shimano Ultegra R8150 Di2 front |
| Cassette | Shimano Ultegra | Shimano Ultegra |
| Chain | Shimano XT M8100 | Shimano Ultegra |
| Crankset | Shimano Ultegra R81000 | Shimano Ultegra R8100 |
| Wheelset | Roval Alpinist CL II | Roval C38 |
| Tire | Specialized S-Works Turbo 2BR | Specialized S-Works Turbo |
| Brake | Shimano Ultegra R8170 | Shimano Ultegra R8170 Di2, Shimano Ultegra R8170 Di2 rear |
| Seatpost | Roval Alpinist | Specialized S-Works Tarmac SL8 |
| Saddle | Specialized Power | Specialized Power Expert |
| Fork | not listed | Specialized FACT 10r Carbon |
| Chainring | not listed | Shimano Ultegra |
| Bottom bracket | not listed | Shimano Ultegra |
| Rotor | not listed | Shimano Ultegra |
| Handlebar | not listed | Specialized Expert Shallow Drop |
| Stem | not listed | Specialized Tarmac |
| Bar tape | not listed | Supacaz Super Sticky Kush |
| Headset | not listed | Integrated |
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