Specialized S-Works Tarmac SL8 Dura-Ace: First ride review

For more than a decade, the Tarmac has been the flagship race bike at the top of the Specialized range. Despite a seven-year stint in which it shared the top spot with the aero Venge, Tarmac has always been the brand's best road bike. That became even more definitive when in 2020, the brand killed off the Venge, saying the Tarmac SL7 was the 'one bike to rule them all.' 

The Tarmac SL8 is the next evolution of that bike. Launched at the World Championships in 2023, the Specialized Tarmac SL8 claims to be "the fastest race bike in the world." It also boasted a full house in the game of bike launch buzzword bingo, being described as faster, lighter, stiffer and more compliant than the outgoing Tarmac SL7.

It's a hero product with a price tag to match, but interestingly, at the time of launch it is cheaper than the outgoing Tarmac SL7. The S-Works model SL8 is currently priced at £12,000 / $14,000 / €14,000 / AU$19,900. That's a full £1000 cheaper than the current SL7 for UK buyers, while international pricing is slightly closer.

Of course, that's still not exactly cheap, but there are more affordable options in the range, with full builds starting at £6,000 / $6,500 / €6,500 / AU9,400. 

A thoroughbred race bike, the Tarmac SL8 is aimed at those who want to go fast on all manner of road topography. Alongside that quote of being the "fastest race bike," Specialized also touts it as the "lightest bike on the WorldTour," claiming it can save 20 seconds over the Col du Tourmalet, or 4 seconds up the Poggio at the end of Milan-San Remo. 

Its positioning puts it in direct competition with other flagship all-rounders bikes from world-renowned brands, including the Cannondale SuperSix Evo, the Pinarello Dogma F, the Giant Propel, and the Canyon Ultimate among others. 

On the morning of the World Championships Elite Men's road race, just a few hours prior to the bike's launch, I had the opportunity to take the new Tarmac SL8 for a two-hour ride on the outskirts of Glasgow. 

If you're after the nitty gritty details of the bike and the development that went into it, check out my launch story, but for my first impressions of the bike, keep reading. 

Design and aesthetics

Given most of this information is covered in depth in the aforementioned launch story, I'll keep this section focused on the top-line stuff for now. When this first-ride review is updated into a full in-depth review, I will dive into the details. 

The first thing to say is that the Tarmac SL8 is still a Tarmac. The DNA of the outgoing model is still abundantly evident, so those who have owned a prior iteration are going to get an immediate sense of familiarity. The geometry remains unchanged, and even though it has seen significant evolution, the aesthetic still bears a resemblance to its forebear. 

Those evolutions I mention pertain to an aero focus up front, a weight and comfort focus at the rear, and a piece-by-piece attention to carbon layup to aid stiffness throughout. 

That aero focus up front includes a new 'Speed Sniffer' (their words, not mine) nose cone up front, effectively deepening the head tube by extending it forwards over the crown of the fork. Much was said about the aesthetics of the bike when photos leaked prior to the official launch, and I'll admit I was among the critics at first. In real life, however, it looks much more unassuming and natural. It's a total non-issue in my opinion. 

At the rear, Specialized says that the turbulent air of a rider's legs means that deep airfoil seat tubes provide vanishingly small aero gains, so instead used this area to shed weight and add compliance. It thinned the seat tube the width of the outgoing SL7 seatpost, making the SL8 seatpost so narrow that a Di2 battery doesn't fit inside, instead mounting to a clip beneath. 

It also made the seat tube approximately 10% shallower, in turn increasing its flex, adding 6% more compliance. 

The resulting frame, according to the brand, is 16 seconds faster over 40km, 115g lighter, 33% stiffer, and 6% more compliant than the SL7. A 56cm S-Works frame is said to weigh 685g, while a Fact 10R frame adds approximately 100 grams. 

Both tiers of frame are compatible with electronic groupsets only. They feature a BSA threaded bottom bracket, and integrated cable routing similar to the SL7, and the same clearance for 32mm tyres.

Specs and build

For my short test ride, I was aboard an S-Works model with Dura-Ace Di2. 

Available builds on the frame also cover SRAM Red, Force and Rival, as well as Ultegra Di2. There is no Shimano 105 Di2, nor is there a Campagnolo Super Record Wireless option. No 1X builds will be available at launch, but the front derailleur hanger can be removed and replaced with a cover to keep dirt ingress out of the holes. It looks cleaner too. 

As per the factory spec, my bike was fitted with Roval Rapide CLX II wheels and the Roval Rapide cockpit. My bike was built specifically for this test ride, and thus, the cockpit dimensions were chosen specifically for my preferred fit. Paying customers won't get quite such a luxury service, unfortunately. 

With that said, Specialized does recognise that being forced to buy an additional $500 cockpit isn't something anyone is happy about doing when they've just spent $14,000 on a bike. A Specialized spokesman told me that it will rely on its retail partners to make the call on whether to swap the bars at the point of purchase. To make this easier, the S-Works bikes will ship with the cockpit in its own aftermarket packaging rather than loose or pre-fitted to the frame. 

Interestingly, my bike also fitted with the uber-fancy 3D-printed S-Works Romin with Mirror saddle, rather than the S-Works Power that would come on the bike if you bought it. Therefore it was pretty tough to tell whether the seatpost's claimed improvement in compliance wasn't just coming through the comfortable saddle. 

All bikes will be shipped with 26C tyres, as well as the 15mm setback seatpost. (A 0mm option is also aftermarket).

First ride impressions

As mentioned earlier, those who have ridden the SL7 will get aboard the SL8 and feel a sense of familiarity. I have ridden the S-Works SL7, and I personally own an S-Works SL6, so I felt right at home on the new bike. 

I'll admit that probably boosted my perspective of the bike's performance somewhat, but I also think it helped me to notice a couple of points where it differs. 

A test ride is typically an opportunity to consider whether a product meets the claims set out by the brand's marketing team. Given that Specialized claimed improvements in more areas than Movistar have Grand Tour leaders, this was going to be a busy test ride. 

The area that stood out the most for me was in the bike's handling. The Tarmac has never been bad at going around corners, in fact, it's always been genuinely excellent. I remember the feeling of railing hairpins in criteriums on my SL6 and coming out of the corner carrying more speed than anyone around me (Turbo Cottons are still excellent tyres). The same feeling was there on the SL7, and if you asked me where I thought there might be room for improvement when designing the SL8, handling would be right at the bottom of my list. 

But having ridden the bike this morning, it feels like it's on a totally different level. Zig-zagging in and out of white lines at the side of the road, the bike's handling was snappy and direct. That front-end stiffness, likely aided by the one-piece cockpit, was immediately apparent. 

For the ride, the roads were wet in places and dry in others, there was standing water and puddles on the apexes of corners, and there was mud and pea-sized gravel strewn across roads at random. The conditions were arguably among the worst you can have for testing handling. When I'm on a new bike, on unfamiliar roads, especially roads like this, I am typically wary of taking risks in corners. 

But here, I didn't get that wariness. I was finding myself taking corners at full speed, staying off the brakes that little bit longer and leaning in that little bit further. It could simply be that the confidence came from the familiarity I mentioned, but I immediately felt like it had more to give in this regard than the SL7. 

When sprinting, both uphill and on the flat, the stiffness at the rear of the bike was excellent too. I managed to hit a peak power that I don't think I've hit all year, so while that's not very scientific and could well be a total coincidence or a high-reading power, it was a good sign.

It also confirms the more valuable insight that the bottom bracket just felt rock solid and the power transfer felt immediate. The front-end stiffness that aided the handling was also apparent here in high-power efforts, yanking on the bars to get as much power out as possible, they just felt immovable. This could be the cockpit alone, or the new carbon layup. I don't know for sure, but it's likely a combination of all things. 

A couple of points I was unable to tease out in today's ride were any aerodynamic improvements and the additional compliance. That's definitely not to say I had a bad experience here; it's certainly not slow and nor is it uncomfortable, so perhaps that's all you need to know. 

On the aero point, I'm conscious that a claimed 16-second saving over a 40km time trial is never going to be possible to feel, it would even be difficult to quantify without a velodrome or a wind tunnel. Interestingly, Specialized admits that more than half of it comes from the Roval cockpit. 

Regardless of any old-versus-new comparisons, the Tarmac SL8 still feels fast. There were points where I could coast down a hill and carry that speed up and over the next, getting up to speed felt easy, and holding 30km/h wasn't proving difficult. It's early days yet, so while it's impossible to draw a definitive conclusion, the early signs are good. 

On the compliance and comfort front, it's worth reiterating that this is a race bike. It's stiff and purposeful so if you roll over a rough surface, you're going to know about it. As with the aero point above, I can't 'feel' a 6% boost in compliance but I did find it to be comfortable. How much of that is due to the 3D-printed saddle I had fitted is hard to say. 

For now, though, the logic of a shallower seatpost adding compliance adds up, and my experience does nothing to oppose the claim. 

Early verdict

From what Specialized is saying, it has taken an already excellent road bike and made it better in every regard, and that is a feat worth celebrating. Of course, with such little time on the bike, it's impossible to draw a definitive conclusion on whether the bike's performance matches those claims, but the early impressions are good

It feels stiff under power and fast in every way, not just aerodynamically but under acceleration too. It's comfortable, although that's caveated by the saddle swap, and the handling has somehow taken the already-excellent Tarmac handling and taken it to a new level. 

The price is high, there's no getting around that, but the fact you get all this at a price that, at the time of launch, is cheaper than the SL7 is incredible. 

And finally, unlike some bikes, such as the unreleased BMC we spotted at the Tour de France which looks fast standing still, the Specialized Tarmac SL8 actually looks rather unassuming. I like that.