2025 Specialized Aethos Shimano vs 2026 Specialized Tarmac SL8 Pro Shimano
The 58 is the Specialized Tarmac SL8 Pro Shimano size closest to your 58 Specialized Aethos Shimano. 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 Tarmac SL8 Pro Shimano
Compared with the Specialized Aethos Shimano in 58, the Specialized Tarmac SL8 Pro Shimano in 58 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
- n/a
- One of the bikes has no number for this
- Head angle
- ±0.0°
- About the same head angle
- Chainstays
- ±0 mm
- About the same
The two frames
Only the Specialized Aethos Shimano 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 Shimano 58 | Specialized Tarmac SL8 Pro Shimano 58 | Difference |
|---|---|---|---|
| Reach | 402mm | 402 | ±0 mm |
| Stack | 591mm | 591 | ±0 mm |
| Head tube angle | 73.5° | 73.5 | ±0.0° |
| Seat tube angle | 73.5° | 73.5 | ±0.0° |
| Effective top tube | 577mm | not listed | |
| Chainstay length | 410mm | 410 | ±0 mm |
| Wheelbase | 1005mm | not listed | |
| BB drop | 72mm | not listed | |
| BB height | 268mm | not listed | |
| Standover | 796mm | not listed | |
| Seat tube length | 532mm | not listed | |
| Fork length | 369mm | not listed | |
| Head tube length | 184mm | 184 | ±0 mm |
Differences are the Specialized Tarmac SL8 Pro Shimano minus the Specialized Aethos Shimano. Full charts: 2025 Specialized Aethos Shimano, 2026 Specialized Tarmac SL8 Pro Shimano.
Where each sits in its class
Specialized Aethos ShimanoSpecialized 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 ShimanoS-Works - Shimano Dura-Ace Di2 | Specialized Tarmac SL8 Pro ShimanoPro - Shimano Ultegra Di2 |
|---|---|---|
| Frame | Specialized Aethos | Specialized Tarmac SL8 |
| Shifter | Shimano Dura-Ace R9270 | Shimano Ultegra R8170 |
| Derailleur | Shimano Dura-Ace R9250 | Shimano Ultegra R8150 Di2 |
| Cassette | Shimano Dura-Ace | Shimano Ultegra |
| Chain | Shimano XTR M9100 | Shimano XT M8100 |
| Crankset | Shimano Dura-Ace R9200 | Shimano Ultegra R81000 |
| Bottom bracket | Shimano Dura-Ace | Shimano Threaded BSA |
| Wheelset | Roval Alpinist | Roval Rapide CL III |
| Tire | Specialized S-Works Turbo 2BR | Specialized S-Works Turbo |
| Brake | Shimano Dura-Ace R9200 | Shimano Ultegra R8170 |
| Seatpost | Roval Alpinist | Specialized S-Works Tarmac SL8 |
| Saddle | Specialized S-Works Power | Specialized Power Pro |
| Fork | not listed | Specialized FACT 10r |
| 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 |
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