2025 Specialized Aethos vs 2026 Specialized Tarmac SL8 Pro Shimano
The Specialized Tarmac SL8 Pro Shimano size closest to your 54 is the 54. Compare the 54 instead
What changes on the Specialized Tarmac SL8 Pro Shimano
Compared with the Specialized Aethos in 54, the Specialized Tarmac SL8 Pro Shimano in 58 places the top of the head tube 47 mm higher and 18 mm further forward, relative to the bottom bracket.
- Frame stack
- +47 mm
- Higher front end
- Frame reach
- +18 mm
- Longer frame reach
- Wheelbase
- n/a
- One of the bikes has no number for this
- Head angle
- +0.5°
- Steeper: sharper steering
- Chainstays
- ±0 mm
- About the same
The two frames
Only the Specialized Aethos is drawn. The Specialized Tarmac SL8 Pro Shimano numbers we have for size 58 are missing the wheelbase.
Geometry side by side
| Measurement | Specialized Aethos 54 | Specialized Tarmac SL8 Pro Shimano 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° |
| Effective top tube | 540mm | not listed | |
| Chainstay length | 410mm | 410 | ±0 mm |
| Wheelbase | 978mm | not listed | |
| BB drop | 72mm | not listed | |
| BB height | 268mm | not listed | |
| Standover | 748mm | not listed | |
| Seat tube length | 481mm | not listed | |
| Fork length | 369mm | not listed | |
| Head tube length | 137mm | 184 | +47 mm |
Differences are the Specialized Tarmac SL8 Pro Shimano minus the Specialized Aethos. Full charts: 2025 Specialized Aethos, 2026 Specialized Tarmac SL8 Pro Shimano.
Where each sits in its class
Specialized AethosSpecialized 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 | Specialized Tarmac SL8 Pro ShimanoPro - Shimano Ultegra Di2 |
|---|---|---|
| Frame | not listed | Specialized 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 |
| Seatpost | not listed | Specialized S-Works Tarmac SL8 |
| Saddle | not listed | Specialized Power Pro |
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