2025 Specialized Roubaix SL8 FACT 12R Carbon vs 2027 Trek Domane AL 4 Gen 4
The 49 is the Trek Domane AL 4 Gen 4 size closest to your 44 Specialized Roubaix SL8 FACT 12R Carbon. 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 Trek Domane AL 4 Gen 4
Compared with the Specialized Roubaix SL8 FACT 12R Carbon in 44, the Trek Domane AL 4 Gen 4 in 49 places the top of the head tube 3 mm lower and 15 mm further forward, relative to the bottom bracket. Its wheelbase is 7 mm longer, which can contribute to stability at speed.
- Frame stack
- −3 mm
- Lower front end
- Frame reach
- +15 mm
- Longer frame reach
- Wheelbase
- +7 mm
- Longer: steadier at speed
- Head angle
- +1.5°
- Steeper: sharper steering
- Chainstays
- +7 mm
- Longer: more planted
The two frames
Specialized Roubaix SL8 FACT 12R Carbon, 44Trek Domane AL 4 Gen 4, 49Drawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Specialized Roubaix SL8 FACT 12R Carbon 44 | Trek Domane AL 4 Gen 4 49 | Difference |
|---|---|---|---|
| Reach | 353mm | 368 | +15 mm |
| Stack | 543mm | 540 | −3 mm |
| Head tube angle | 69.3° | 70.8 | +1.5° |
| Seat tube angle | 75° | 74.6 | −0.4° |
| Effective top tube | 503mm | 516 | +13 mm |
| Chainstay length | 418mm | 425 | +7 mm |
| Wheelbase | 994mm | 1001 | +7 mm |
| BB drop | 80mm | 80 | ±0 mm |
| BB height | 269mm | not listed | |
| Standover | 686mm | 717 | +31 mm |
| Seat tube length | 365mm | 440 | +75 mm |
| Fork length | 375mm | not listed | |
| Head tube length | 90mm | 123 | +33 mm |
Differences are the Trek Domane AL 4 Gen 4 minus the Specialized Roubaix SL8 FACT 12R Carbon. Full charts: 2025 Specialized Roubaix SL8 FACT 12R Carbon, 2027 Trek Domane AL 4 Gen 4.
Where each sits in its class
Specialized Roubaix SL8 FACT 12R CarbonTrek Domane AL 4 Gen 4
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 Roubaix SL8 FACT 12R CarbonS-Works SL8 FACT 12R Carbon | Trek Domane AL 4 Gen 4Gen 4 |
|---|---|---|
| Fork | Specialized Future Shock 3.3 | Trek Domane AL |
| Seatpost | Specialized S-Works Pave Seat post | Bontrager Comp |
| Frame | not listed | Trek Domane AL |
| Shifter | not listed | Shimano Tiagra R4020 |
| Derailleur | not listed | Shimano Tiagra R4000, Shimano Tiagra 4700 |
| Cassette | not listed | Shimano RS400 |
| Chain | not listed | Shimano LG500 |
| Crankset | not listed | Shimano Tiagra R4000 |
| Chainring | not listed | Shimano Tiagra 4700 |
| Bottom bracket | not listed | Shimano RS501 |
| Wheelset | not listed | Bontrager Paradigm 23 |
| Tire | not listed | Bontrager Kwaremont |
| Hub | not listed | Formula RX-142, Formula RX-512 |
| Rim | not listed | Bontrager Paradigm 23 |
| Rotor | not listed | Shimano SM-RT66 |
| Handlebar | not listed | Bontrager Comp |
| Stem | not listed | Bontrager Elite |
| Bar tape | not listed | Bontrager Supertack Perf |
| Headset | not listed | Bontrager Expander Plug |
| Saddle | not listed | Trek Verse Short |
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