2025 Trek Madone SL Gen 8 vs 2026 Specialized Tarmac SL8 Pro Shimano
The 58 is the Specialized Tarmac SL8 Pro Shimano size closest to your L Trek Madone SL Gen 8. 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 Trek Madone SL Gen 8 in L, the Specialized Tarmac SL8 Pro Shimano in 58 places the top of the head tube 9 mm higher and 8 mm further forward, relative to the bottom bracket.
- Frame stack
- +9 mm
- Higher front end
- Frame reach
- +8 mm
- Longer frame reach
- Wheelbase
- n/a
- One of the bikes has no number for this
- Head angle
- −0.3°
- About the same head angle
- Chainstays
- −1 mm
- About the same
The two frames
Only the Trek Madone SL Gen 8 is drawn. The Specialized Tarmac SL8 Pro Shimano numbers we have for size 58 are missing the wheelbase.
Geometry side by side
| Measurement | Trek Madone SL Gen 8 L | Specialized Tarmac SL8 Pro Shimano 58 | Difference |
|---|---|---|---|
| Reach | 394 | 402 | +8 mm |
| Stack | 582 | 591 | +9 mm |
| Head tube angle | 73.80 | 73.5 | −0.3° |
| Seat tube angle | 73.40 | 73.5 | +0.1° |
| Effective top tube | 568 | not listed | |
| Chainstay length | 411 | 410 | −1 mm |
| Wheelbase | 990 | not listed | |
| Standover | 820 | not listed | |
| Seat tube length | 548 | not listed | |
| Head tube length | 172 | 184 | +12 mm |
Differences are the Specialized Tarmac SL8 Pro Shimano minus the Trek Madone SL Gen 8. Full charts: 2025 Trek Madone SL Gen 8, 2026 Specialized Tarmac SL8 Pro Shimano.
Where each sits in its class
Trek Madone SL Gen 8Specialized 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 | Trek Madone SL Gen 8SL 5 Gen 8 | Specialized Tarmac SL8 Pro ShimanoPro - Shimano Ultegra Di2 |
|---|---|---|
| Frame | Trek 500 Series OCLV Carbon | Specialized Tarmac SL8 |
| Fork | Trek Madone | Specialized FACT 10r |
| Shifter | Shimano 105 | Shimano Ultegra R8170 |
| Derailleur | Shimano 105 R7100 | Shimano Ultegra R8150 Di2 |
| Cassette | Shimano 105 R7101 | Shimano Ultegra |
| Chain | Shimano SLX M7100 | Shimano XT M8100 |
| Crankset | Shimano 105 R7100 | Shimano Ultegra R81000 |
| Bottom bracket | Praxis T47 | Shimano Threaded BSA |
| Wheelset | Bontrager Paradigm SL | Roval Rapide CL III |
| Tire | Bontrager R1 | Specialized S-Works Turbo |
| Brake | Shimano 105 | Shimano Ultegra R8170 |
| Rotor | Shimano SM-RT70 | Shimano Ultegra R8170 |
| Handlebar | Bontrager Comp | Roval Rapide Cockpit |
| Stem | Trek RCS | Roval Rapide Cockpit |
| Headset | Trek RCS | not listed |
| Seatpost | Trek Madone | Specialized S-Works Tarmac SL8 |
| Saddle | Bontrager Aeolus | Specialized Power Pro |
| Bar tape | not listed | Supacaz Super Sticky Kush |
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