Last Updated on 4 August 2025 by Chris
During our summer collection photoshoot on Gran Canaria (here’s a blog post from one of our earlier trips), we had the chance not only to capture visuals in a stunning environment, but also to see how one of the world’s most talked-about bikes performs in the real world – the Specialized S‑Works Tarmac SL8.
Important: this review is not sponsored. We purchased the bikes ourselves – deliberately and with full intention. We wanted the gear featured in our photos to match the aesthetics and quality of the clothing we design. And frankly… we just wanted to find out if the difference is real. That’s how this article came to be – no sponsorship, no bias 🙂
Canary climbs and descents as proving grounds for the S-Works SL8
Krzysiek and Dominik spent nearly 30 days riding and testing two identical Tarmac S-Works SL8 bikes – the exact setup we’re reviewing here. Mountain switchbacks, long descents, and gusty winds provided the perfect terrain to see if the marketing promises hold up. Is this really the most advanced road bike ever made? We got up close and personal.
The SL8 combines the aerodynamic lines of the Venge with the lightness and comfort of the Aethos. Its distinctive “Speed Sniffer” head tube profile makes it 16.6 seconds faster over 40 km compared to the SL7.
The frame weighs just 685 g (size 56), making it 15% lighter than the SL7, with a 33% improvement in stiffness-to-weight ratio.
That’s what the manufacturer claims on their official website: Specialized.com. But is it all true? The weight – definitely. The rest? Hard to verify. We have to take their word for it.
Why did we buy two S-Works SL8 bikes?
The decision to buy the S-Works Tarmac SL8 wasn’t random. From the very beginning, we wanted bikes in our Luxa summer collection photoshoot that would match our apparel in terms of design and premium quality.
That’s why we chose the SL8 – a model that’s been described since its launch as “the most advanced Tarmac ever” and one that combines everything we care about: aerodynamics, lightness, comfort and aesthetics.
We needed two units, in a specific size and configuration, that would not only look great in the photos, but could also be tested properly in the conditions we usually ride in: long climbs, strong winds, and varied road surfaces.
The SL8 was a natural choice – not only because of Specialized’s reputation, but also because we knew the previous SL6 model very well and were curious whether this new generation really makes a difference.
Technical specifications of our SL8 builds:
| Component | Specification |
|---|---|
| Frame | Specialized S-Works Tarmac SL8 |
| Frame size | 54 cm |
| Groupset | Shimano Dura-Ace Di2 R9270 |
| Cassette | Shimano Dura-Ace 12s 11-30T |
| Crankset | Shimano Dura-Ace 52/36T |
| Brakes | Shimano Dura-Ace R9270 hydraulic |
| Wheels | SBK 44 Carbon Disc (24 mm internal width), DT Swiss 240s hubs |
| Tyres | Continental Grand Prix 5000 28 mm |
| Handlebar | Roval Rapide Integrated Cockpit |
| Stem | Integrated (part of the Roval cockpit) |
| Saddle | Prologo |
| Power meter | Inpeak POWERCRANK-E single |
| Total weight | 7.0 kg (with pedals, Wahoo, and bottle cages) |
Shimano Ultegra vs Dura-Ace
Our previous bikes were equipped with the Ultegra Di2 groupset and an 11-speed cassette. With the new setup, the S-Works builds received the latest Dura-Ace Di2 paired with a 12-speed cassette.
Do I feel any difference between the two groupsets? Honestly – not really.
Krzysiek
The older Ultegra shifts just as precisely and quickly. Sure, the 12-speed cassette gives you an extra cog, which is definitely a plus. But in terms of actual performance – there’s little difference. The only real change is weight – and yes, Dura-Ace is lighter (as expected).
One surprise with the new Dura-Ace is its relatively short battery life (the battery is hidden inside the seatpost). It lasted just 2-3 weeks of moderate riding in the mountains. With our older SL6 on Ultegra, we could easily forget about charging for 6-10 weeks.
First impressions after switching from the older SL6
Before jumping on the SL8, we had spent several years riding the Tarmac Disc Expert SL6 – a bike that, despite its age, still stands as a solid, well-rounded machine. It gave us plenty of joy on long rides, handled descents with confidence, remained stiff under power, and at the time — felt fast.
It wasn’t until we directly switched to the Specialized S-Works Tarmac SL8 that we realized just how far this platform has evolved. Of course, our previous bikes weren’t top-of-the-line S-Works builds which makes the contrast even more noticeable.
The SL8 is noticeably stiffer in sprints, more responsive on climbs, and surprisingly more comfortable on long rides – despite its more aggressive fit. We also felt the difference in weight -our previous Tarmacs were about 1 kg heavier. These new builds (SL8 + Wahoo + pedals + bottle cages) weigh exactly 7.0 kg, ready to ride.
Initial thoughts after the first ride
On our first day after arriving on the island, we went for a short ride to San Bartolomé – around 70 km and 1,400 m of elevation gain. A perfect way to reconnect with the terrain and finally put the new bikes to use. It was literally the first real ride – the bikes had arrived just before our flight, and Polish winter left no room for a test spin beforehand. So we had no idea what to expect.
CLIMBING – how does the S-Works SL8 perform?
The first few strong pedal strokes and you immediately feel the bike surging forward. Compared to our older SL6s, the difference is noticeable after just a few revolutions. On steady climbs with a consistent power output, it’s hard to say exactly how much faster it is – only a lab test would reveal that. The bikes are roughly 1 kg lighter and likely more aerodynamic. What we can say for sure: the S-Works responds to accelerations with incredible sharpness.
On long climbs like the iconic Pico de las Nieves or the Valley of the Tears, the difference compared to our previous bikes became obvious with every passing kilometer. It’s not just about watts – it’s about the feeling that the bike actually wants to go uphill. And you don’t feel like anything is holding you back.
Segment times on similar power also confirmed we’re climbing faster than before.
DESCENDING – is the Tarmac fast downhill?
Fast descents on the SL8 are a different league. The bike holds its line like it’s on rails. No wobble, no twitchiness, no mid-corner corrections – it simply goes where you point it. Even at speeds well over 70 km/h, it inspires full confidence, as if glued to the tarmac.
Every steering input is precise and immediate. No fighting the bike in tight corners. Even on technical, twisty descents around Fataga, the Tarmac behaved like a machine with autopilot engaged. Zero nervousness, no delay in response. Just pure speed enjoyment.
This is the kind of bike that doesn’t just allow you to descend faster – it encourages it, building trust with every corner.
Polish components – our custom upgrades
Although the Tarmac S-Works SL8 is a world-class bike, our builds proudly feature components made in Poland. We deliberately chose Szobak SBK 44 wheels and a power meter by Inpeak, mounted on the left Dura-Ace crank arm.
We believe in Polish products that match global standards – in both technology and craftsmanship. You can read more about our approach to conscious sourcing and manufacturing in our Manifesto.
SBK 44 wheels – comfort and cornering performance
A huge contributor to the overall comfort on Gran Canaria’s bumpy, sunbaked roads were the SBK 44 wheels, built with carbon rims featuring a 24 mm internal width. Paired with lower pressure and wide tires, the bike practically glides over rough surfaces without sacrificing stiffness or precision. The wheels were built on DT Swiss 240s hubs and Cx-Ray spokes.
It’s worth mentioning that Gran Canaria still has its fair share of poor road surfaces – it’s getting better year by year, but far from perfect. I remember being there back in 2015, when nobody even considered riding tires wider than 25 mm. Back then, we were really getting beaten up by the tarmac but at the time, we didn’t realize that a road bike could actually be comfortable even on rough surfaces.
Our current S-Works test bikes are equipped with Continental Grand Prix 5000 tires, 28 mm on one and 30 mm on the other. They sit flush with the rims, creating a clean aerodynamic profile and enhancing cornering stability. The wheelset weighs in at 1390 g.
Conclusion – is the S-Works SL8 worth its price?
The Tarmac S‑Works SL8 doesn’t pretend to be anything it’s not. It doesn’t try to be accessible. It’s an uncompromising machine built for those who know what they’re looking for – and are willing to pay for it.
On the roads of Gran Canaria, it revealed its full character: light on climbs, stable on descents, razor-sharp in response and impressively aerodynamic at high speeds. Add to that the beautiful design – though that part is of course subjective. It’s a bike that turned heads both while riding and when parked outside a café.
Is the SL8 a perfect bike?
The first thing that might scare off potential buyers is, of course, the price. For many, it’s simply a deal-breaker. One could also criticize the limited adjustability of the cockpit, especially for riders who prefer a traditional bar-and-stem setup. For us, that’s not an issue – especially since the integrated cockpit can be easily removed when packing the bike in a travel case.
The differences compared to cheaper bikes (especially older ones) are real, but not as dramatic as some marketing materials suggest.
However, if cycling means more to you than just exercise if you care about watts, but also appreciate design, precision, and the feeling of riding something top-tier the SL8 delivers all of that flawlessly.
This isn’t just a bike that rides well. It’s a bike that makes you want to ride more.
PROS:
- Outstanding stiffness and responsiveness, especially in sprints and climbs
- Low weight: 7.0 kg in ride-ready configuration
- Great stability and confidence on descents
- Quiet, smooth and reliable performance
- Light and comfortable SBK 44 wheels made in Poland
- Prestige, aesthetics, and alignment with our Luxa brand identity
CONS:
- High price
- Not fully hidden cables at the cockpit (though not visible when riding)
- Limited flexibility to customize components when buying a complete build
