Top of the class?: The Specialized S-Works Tarmac SL9 put to the test

​Less than three years ago, the Tarmac SL8 set new standards in the TOUR road bike test. Awarded a record-breaking top mark under the complex assessment scheme, it was regarded as one of the most versatile competition bikes on the market – a bike with no real weaknesses. Strong in its core discipline of aerodynamics, outstanding in terms of weight: with a frame weighing just 723 grams and a total weight of 6.6 kilograms, even the latest specialised lightweight models from established brands struggle to keep up.

However, a great deal has happened in the very fast-moving road bike market during this model’s short lifespan. A handful of competitors were on a par in terms of marks, particularly as they are slightly faster aerodynamically than the SL8. Then, in the spring of 2026, the updated Giant Propel was launched, changing the game: The new Propel outperformed the previous record – which had been shared, to varying degrees, by Canyon (Aeroad), Giant (with the previous-generation Propel), Specialized and Scott (with the lightweight Addict and the fast Foil) – by a tenth of a point. Can the revamped SL9 reclaim the crown for the Americans? After all, the developers promise to have squeezed even more out of it in terms of both weight and aerodynamics.

Targeted fine-tuning

If you place the SL9 next to the SL8, you’ll notice striking differences in the silhouette, but not a radical departure from the original design. Instead, Specialised has optimised key areas. This comes as no surprise: after all, the SL8 was so perfect that a complete redesign would have made little sense. The most noticeable change is to the seat tube. It wraps round the rear wheel a little further than on the SL8, and the seat stays are set slightly lower. Anyone familiar with the Canyon Aeroad will inevitably spot similarities in this area. There have also been some changes at the front end, even if they are less noticeable from the outside. The head tube is slimmer at the front, which required a great deal of engineering effort: to provide sufficient space for the brake lines despite the narrower cross-section, a specially developed steerer tube design was needed. The steerer tube is now D-shaped and flattened at the sides; the cables run along this surface. The fork itself has also been redesigned. Viewed from the front, the fork legs appear narrower but flare out more; from the side, the fork crown looks slightly more substantial than before. The seatpost is also new and ‘aerodynamised’: it is now extremely slender in the upper third and features an extended, aerodynamic profile. That said, the distinctive, dynamic sweep of the top tube has been retained, albeit in a more subdued form – very much in keeping with the tradition of the Tarmac range.

The bike still looks elegant and delicate, and the design isn’t over the top. As well as improving aerodynamics, Specialised has also reduced the weight of the SL9. The S-Works SL9 now weighs in at 6,490 grams on the TOUR scales, a reduction of 60 grams compared to the lightest SL8. However, this figure includes significantly wider tyres (now 30 millimetres instead of the previous 26 millimetres), which is why the 150-gram weight saving, according to the manufacturer’s specifications, is likely to be close to reality. The frame’s wall thickness has been revised without compromising on stiffness or durability. On our test benches, the SL9’s ultra-light chassis once again achieves top marks across the board. The biggest single contribution, however, comes from the carbon spokes used to build the new Roval Sprint wheelsets. They completely offset the added weight of the wide tyres; the front wheel is even 50 grams lighter. The cockpit, featuring the flat aero handlebars, is based on the original design of the SL8 but has been refined in its details. It sits comfortably in the hands, places the rider in an aerodynamically favourable position and allows for a natural posture without extreme stretching.

Measurable improvement in the wind tunnel

Like all competition bikes in the TOUR test, the SL9 had to prove itself in the GST wind tunnel in Immenstaad. The result is clear: the 205 watts of pedalling power required to overcome air resistance at 45 km/h is on a par with specialised aero road bikes. Compared with the SL8, this represents an improvement of four watts – a significant step forward given the modest visual changes and the noticeably wider tyres. Only part of this improvement is attributable to the detailed aerodynamic modifications to the head tube, fork and seatpost. The new Roval wheels contribute an improvement of around two watts, as a comparison with our reference wheels shows. In absolute terms, this is not a top figure, The fastest bikes in the latest TOUR test report now reach 195 watts – ten watts less than the SL9. However, these bikes are specialised aero machines that trade their wind tunnel advantage for significantly greater weight, a stiff to hard ride quality, and limited suitability for everyday use. Among the all-rounders, though, the SL9 comes out well ahead; above all, it offers a slight advantage over its main rival, the Giant Propel: It didn’t exceed 209 watts – which is almost disappointing for a dedicated aero model – whilst being only marginally lighter than the Tarmac.

A real force to be reckoned with in terms of driving dynamics

Our first impression out on the road: it’s amazing how well it rolls! The supple tyres with their cotton carcass offer a riding experience all of their own; their distinctive rolling sound is amplified by the substantial carbon rims and encourages you to pedal hard. The SL9’s geometry remains unchanged from its predecessor – fans of the distinctive Tarmac ride feel are sure to welcome this wholeheartedly. The bike sits on the road with its usual stability and precision, feels incredibly manoeuvrable, tackles bends directly and with plenty of feedback, and lets the rider know exactly what’s happening beneath them at all times. Despite its featherweight, you always feel as though you’re in control of a stable bike. The sporty, stretched but not extreme riding position suits the character of a competition bike that can be ridden comfortably even on long tours. When it comes to comfort, too, the SL9 hits the mark exactly where the SL8 had its ‘sweet spot’. The measured frame comfort is almost identical to that of its predecessor, which is perfectly acceptable given the high standard. The slightly wider tyre options now available nevertheless make a pleasant, noticeable difference on poor road surfaces.

A familiar bike, but even better

As familiar as the SL9 may seem, the question of whether it needs to replace the SL8 remains a relevant one. Certainly not in terms of riding enjoyment alone. When it comes to ‘marginal gains’ – that is, the sum of tiny advantages – the SL9 has the upper hand. With an overall score of 1.4, it achieves the current top TOUR rating and draws level with the Giant Propel, which has been the sole leader in the rankings as the world’s best competition road bike since the spring. Two bikes thus share the top spot – and anyone currently looking for a new competition bike is spoilt for choice. The Propel is marginally lighter and slightly more comfortable; Specialized has the edge in the aerodynamics department. What sets the SL9 apart is the very thing that made the SL8 so impressive: hardly any other bike currently combines weight, aerodynamics, handling and comfort better into a harmonious overall package. Or, to put it another way: no other bike gets so little wrong across all categories at the same time.