Racers and fast club riders who want the modern Tarmac. If you came off an SL7, check that the stack/reach still matches your size.
The current Specialized race bike: lighter than SL7, still aero, and famously 'it just disappears' if the fit is right. Size by stack/reach — the 54/56 split is where a lot of riders hop.
Racers and fit riders who want Giant's race geometry without Propel's deep tubes.
Giant's lightweight race bike: compact sloping top tube, sharp steering, and a fit that has been a stack/reach reference for a long time. Less aero drama than Propel.
Riders shopping the newest Tarmac. Compare stack/reach to SL8 before you assume your size letter carries over.
The next Tarmac generation in the catalog window. Treat it as the race-bike successor to SL8: same family, new tubeset — confirm geometry on the year page rather than assuming SL8 numbers.
| Measurement | AlliedAlpha 2025 |  SpecializedTarmac SL8 2025 |  GiantTCR Advanced 2025 |  SpecializedTarmac SL9 2027 |
|---|---|---|---|---|
| Stackmm | 564 | 544−20 | 563−1 | 544−20 |
| Reachmm | 394 | 384−10 | 393−1 | 384−10 |
| Head tube angle° | 73.0 | 73.0 | 73.0 | 72.5−0.5 |
| Seat tube angle° | 73.0 | 74.0+1.0 | 73.0 | 74.0+1.0 |
| Chainstaymm | 408 | 410+2 | 405−3 | 410+2 |
| Wheelbasemm | 998 | 978−20 | 986−12 | 986−12 |
| BB dropmm | 70 | 72+2 | 70 | 72+2 |
| BB heightmm | — | 268 | — | 268 |
| Standovermm | — | 768 | — | 767 |
| Part | Alpha 56 | Tarmac SL8 54 | TCR Advanced ML | Tarmac SL9 54 |
|---|---|---|---|---|
| Stem | 100 mm | 100 mm | 100 mm | 100 mm |
| Bar | 420 mm | 420 mm | 420 mm | 420 mm |
| Crank | 172.5 mm | 172.5 mm | 172.5 mm | 172.5 mm |
That spec retails for £8,250 and is said to weigh 7.16kg in a size 56. You can read Sam's full review here. The Specialized Tarmac SL8 will be at the ...
# Specialized Tarmac SL8 Expert #### VERDICT: - Very Good - Quite good - Not so good ### Specialized SL8 Expert: Ride The SL8 was noticeably comfortable, but there was a sense o…