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S-Works Tarmac SL9 Comparison: Dura-Ace Di2 vs SRAM Red AXS
Last updated: July 2026
Both builds of the S-Works Tarmac SL9 share the exact same 687g FACT 12r carbon frame, Roval Rapide CLX III wheels, and integrated cockpit
— Specialized's flagship road race platform, engineered around lowering total race time rather than one isolated spec.
The only real decision is drivetrain: full Shimano Dura-Ace Di2 or full SRAM Red AXS. Same bike, two electronic ecosystems — here's how to pick the one that's right for you.
See both builds at Fresh Air Kelowna
The S-Works Tarmac SL9 Platform
Every S-Works Tarmac SL9 build starts from the same 687g FACT 12r carbon frame, Rider First Engineered and Win Tunnel Engineered for what Specialized calls the lowest real-world Time to Finish of any road bike they've tested — a claimed 4-watt aero advantage at race speed. Both builds share the same Roval Rapide CLX III wheelset, Roval Rapide integrated cockpit, S-Works Power with Mirror saddle, and S-Works Rapide carbon seatpost. Complete weight lands at 6.6 kg (size 56) either way. From there, the platform splits into two drivetrain ecosystems — Shimano Dura-Ace Di2 or SRAM Red AXS — so the choice comes down to shifting feel and component preference, not frame, wheels, or aero performance.
Key Differences Between Models
- Frame – Identical on both builds: S-Works FACT 12r Carbon, 687g, threaded BB, 12x142mm thru-axle, UDH dropout
- Wheels & Cockpit – Identical on both builds: Roval Rapide CLX III wheels, Roval Rapide integrated bar/stem
- Groupset – Dura-Ace Di2: Shimano ST-R9270 / FD-R9250 / RD-R9250, 12-speed electronic vs Red AXS: 12-speed wireless electronic
- Brakes – Dura-Ace Di2: Shimano BR-R9270 hydraulic disc vs Red AXS: SRAM RED E1 hydraulic disc
- Crankset – Dura-Ace Di2: FC-R9200, 52/36t, with 4iiii Precision Pro power meter vs Red AXS: SRAM RED AXS E1, 50/37t, with Quarq power meter
- Cassette – Dura-Ace Di2: CS-R9200, 11-34t vs Red AXS: XG-1290 E1, 10-36t — noticeably wider range
- Chain – Dura-Ace Di2: Shimano XTR M9100 vs Red AXS: SRAM RED E1
- Bottom Bracket – Dura-Ace Di2: CeramicSpeed Alpha, BSA Threaded Shimano vs Red AXS: CeramicSpeed Alpha, BSA DUB
- Weight – Identical on both builds: 6.6 kg (size 56)
Who Should Choose Dura-Ace Di2
Choose the Dura-Ace Di2 build if you're already in Shimano's ecosystem, prefer its shift feel, or want the slightly tighter 52/36t chainring range for higher top-end speed on flatter routes like Westside Road. It's also the pick if you want a built-in 4iiii power meter without adding a third-party ecosystem to manage.
Who Should Choose SRAM Red AXS
Choose the SRAM Red AXS build if you want fully wireless shifting with no derailleur cables at all, or if you ride mixed terrain around the Okanagan where the wider 10-36t cassette gives real help on steeper pitches like the Naramata Bench climb. It's also the natural pick if you're already running SRAM elsewhere in your setup.
Fresh Air Expert Insight
Riders rarely regret either choice here — the frame and wheels are doing most of the work either way. What actually decides it in our fitting room is usually gear range and ecosystem familiarity: the Red AXS's wider cassette is genuinely useful if the Okanagan's hillier routes are your regular training ground, while Dura-Ace Di2 riders tend to already know exactly why they want it.
— Fresh Air Kelowna road team
Come see it in store and we'll walk you through it.
Why Riders Love the S-Works Tarmac SL9 Platform
- One Fast Frame, Two Ways In – Both builds share the exact aero and weight benchmark, so neither is the "lesser" bike.
- Genuine Aero Gains – Specialized's Speed Sniffer and Win Fin shaping is identical across both drivetrains.
- Matched Wheel Package – Roval Rapide CLX III wheels are tuned to this exact frame on every build.
- Built-In Power Data – Both builds ship with an integrated power meter, no aftermarket unit required.
- Race-Ready Either Way – 6.6 kg complete regardless of which drivetrain you pick.
Full Comparison
| FEATURE | S-Works Tarmac SL9 – Dura-Ace Di2 | S-Works Tarmac SL9 – SRAM Red AXS |
|---|---|---|
| Frame | S-Works FACT 12r Carbon, 687g — identical | |
| Wheels | Roval Rapide CLX III — identical | |
| Cockpit | Roval Rapide Integrated — identical | |
| Groupset | Shimano Dura-Ace Di2 (ST/FD/RD-R9270/9250) | SRAM RED AXS E1 |
| Brakes | Shimano Dura-Ace BR-R9270 | SRAM RED E1 |
| Crankset | 52/36t, 4iiii power meter | 50/37t, Quarq power meter |
| Cassette | 11-34t, 12-speed | 10-36t, 12-speed |
| Chain | Shimano XTR M9100 | SRAM RED E1 |
| Bottom Bracket | CeramicSpeed Alpha, BSA Threaded Shimano | CeramicSpeed Alpha, BSA DUB |
| Weight | 6.6 kg (size 56) — identical | |
| Best For | Shimano ecosystem riders, flatter/faster routes | Wireless shifting, wider gear range for climbing |
Which Should You Choose?
Go Dura-Ace Di2
If you already ride Shimano, want the tighter 52/36t gearing for top-end speed, and prefer wired-internal shifting. It's also the pick if you want a built-in 4iiii power meter without adding a third-party ecosystem to manage. See the Dura-Ace Di2 build.
Go SRAM Red AXS
If you want fully wireless shifting with no derailleur cables at all, or you ride mixed terrain around the Okanagan where the wider 10-36t cassette gives real help on steeper pitches like the Naramata Bench climb. It's also the natural pick if you're already running SRAM elsewhere in your setup. See the SRAM Red AXS build.
See the Tarmac SL9
Everything structural is identical — same FACT 12r frame, Roval Rapide CLX III wheels, cockpit, saddle, and seatpost. The difference is entirely in the drivetrain: groupset, brakes, crank ratio, cassette range, and power meter brand.
Neither — both complete bikes weigh 6.6 kg in a size 56. Component-level weights differ slightly, but they net out to the same total.
Not objectively better — they're different systems. SRAM Red AXS runs fully wireless with no shift cables; Dura-Ace Di2 uses Shimano's wired-internal system. Shift speed and reliability are both excellent; it mostly comes down to ecosystem preference and feel.
The SRAM Red AXS build's 10-36t cassette gives noticeably more range than the Dura-Ace Di2's 11-34t, which helps on steeper Okanagan climbs like the Naramata Bench. Riders prioritizing flatter, faster routes may prefer Dura-Ace Di2's tighter 52/36t chainrings instead.
Both builds share identical geometry, so sizing is the same either way. Our team at Fresh Air Kelowna can fit you properly in person, including a full bike fitting session.
