2027 Trek Madone SL Gen 8 First Replica vs 2025 Specialized Aethos Pro
The 49 is the Specialized Aethos Pro size closest to your XS Trek Madone SL Gen 8 First Replica. 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 Aethos Pro
Compared with the Trek Madone SL Gen 8 First Replica in XS, the Specialized Aethos Pro in 49 places the top of the head tube 7 mm higher and 5 mm further forward, relative to the bottom bracket.
- Frame stack
- +7 mm
- Higher front end
- Frame reach
- +5 mm
- Longer frame reach
- Wheelbase
- +2 mm
- About the same
- Head angle
- +0.2°
- About the same head angle
- Chainstays
- ±0 mm
- About the same
The two frames
We can't draw these frames yet. The Trek Madone SL Gen 8 First Replica numbers we have for size XS are missing the seat angle. The numbers below still compare.
Geometry side by side
| Measurement | Trek Madone SL Gen 8 First Replica XS | Specialized Aethos Pro 49 | Difference |
|---|---|---|---|
| Reach | 370 | 375mm | +5 mm |
| Stack | 507 | 514mm | +7 mm |
| Head tube angle | 71.6° | 71.75° | +0.2° |
| Effective top tube | 517 | 508mm | −9 mm |
| Chainstay length | 410 | 410mm | ±0 mm |
| Wheelbase | 971 | 973mm | +2 mm |
| BB drop | 72 | 74mm | +2 mm |
| Standover | 704 | 705mm | +1 mm |
| Seat tube length | 404 | 431mm | +27 mm |
| Head tube length | 100 | 109mm | +9 mm |
| Seat tube angle | not listed | 75.5° | |
| BB height | not listed | 266mm | |
| Fork length | not listed | 369mm |
Differences are the Specialized Aethos Pro minus the Trek Madone SL Gen 8 First Replica. Full charts: 2027 Trek Madone SL Gen 8 First Replica, 2025 Specialized Aethos Pro.
Where each sits in its class
Trek Madone SL Gen 8 First ReplicaSpecialized 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 | Trek Madone SL Gen 8 First ReplicaSL 7 Gen 8 - The First 50 Replica | Specialized Aethos Pro |
|---|---|---|
| Fork | Trek Madone Gen 8 | not listed |
| Shifter | Shimano Ultegra R8170 Di2 | not listed |
| Derailleur | Shimano Ultegra R8150 Di2 | not listed |
| Cassette | Shimano Ultegra R8101 | not listed |
| Chain | Shimano XT M8100 Ultegra/XT | not listed |
| Crankset | Shimano Ultegra R8100 | not listed |
| Wheelset | Bontrager Aeolus Pro 51 | not listed |
| Tire | Bontrager Aeolus Pro | not listed |
| Brake | Shimano Ultegra | not listed |
| Rotor | Shimano CL800 | not listed |
| Stem | Trek RCS | not listed |
| Seatpost | Trek Madone | not listed |
| Saddle | Bontrager Aeolus Elite | not listed |
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