By a measure of total individual wins, the Specialized Tarmac is the most successful of all the bikes atop the world sporting stage. With the brand new SL6, Specialized claim the triple crown of slicing weight, increasing stiffness and dramatically reducing aerodynamic drag.
Through its various iterations the Tarmac has won numerous World Championships, the Olympic Road Race and all three Grand Tours.
Its previous SL5 edition alone claimed over 200 victories at World Tour level since its release in 2014, being the choice of dozens of Specialized’s top sponsored riders. This redesign, then, grabbles with heavy expectation.
Aerodynamics
While on the surface the Tarmac may look similar, with a near identical geometry for a 56cm frame. It has avoided the highly integrated componentry of Specialized’s Venge VIAS or the comfort focussed FutureShock technology of the Roubaix. Getting up close to the bike, some serious changes were evident.
Aerodynamics is probably the most drastic switch. Having not been targeted before in the Tarmac class, Specialized claim that the new S-Works is equal with the previous generation of Specialized Venge in terms of aero gains.
‘Our tests show that the new Tarmac saves 45 seconds over 40km compared to the current generation of Trek Emonda or Cannondale SuperSix,’ says Chris Yu, Specialized’s Director of Integrated Technologies.
Tube shapes
Most of those gains have come from a redesign of the fork, the seattube and the seaststays. The most visible change is the dropping of the seatstays, which coupled with a direct mount braking setup has neatened up the rear end.
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The revisions of the tube profiles are where the biggest gains have been made.
Where the Tarmac has historically used a standard 27.2mm seatpost, Specialized has now equipped the SL6 with an aerodynamically designed seatpost and seattube with a D-shaped cross section. Specialized claims the new rear end tube shapes increase the overall compliance of the rear end.
A surprising modification is that overall all the tubes are now smaller in diameter than with the previous frame. Specialized claim the tubes to be stiffer and more efficient, arguing that the ‘days of “oversized is stiff” are gone’. The benefit, then, is threefold – reducing weight while increasing stiffness and compliance.
Part of this all around improvement is owing to an increase in the number of overall carbon plies being used – going from 350 pieces in the SL5 edition to 500 pieces in this edition.
Other small touches shouldn’t go unnoticed, such as an increase in the stiffness of the derailleur hanger. While often overlooked the performance of the hanger will significantly influence the performance of the shifting by aligning the mech in the right position.
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Versatility and handling
Specialized have stressed that versatility is the most prominent demand of the new Tarmac SL6 targeting the varied demands of the modern Grand Tour stages.
‘The dynamics of raicng have changed over the years, so a professional racer's needs have changed,’ explains Yu. ‘Every 10 km the decision on which of our previous bikes as most suitable would switch. So that’s why we have taken the decision to make a bike that is appropriate across all different types of stages.’
Handling is of course a prominent element of this, and Specialized claim a considerable gain over what was already considered a benchmark with the SL5. Sponsored rider Peter Sagan described the difference as palpable, ‘It felt like a different bicycle, because it is much stiffer, much better handling… the reaction of bicycle is much better.’
Specialized argues that the smoothness of the ride afforded by these new tube shapes and layup contribute to this improved handling, as well as the newly designed fork.
Sizing specific
The fork has also been adapted to suit separate sizing, with three options of fork length: V1 for sizes 44cm, 49cm and 52cm, V2 for 54cm and 56cm and V3 for sizes 58 and 61cm. The forks become wider and deeper as they match larger frames to compliment the different handling of those larger geometry frames.
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With the acquisition of the Retul fitting program, Specialized has undertaken what it calls a 'Rider First Engineered' approach. Capitalising on fit data to hone geometry across the sizing. As is common in the last few years, Specialized claim that stack and reach ratios graduates in proportion as the sizing scales up from the smallest to largest frames.
The Tarmac has been designed with as a unisex platform, with women’s geometry and broader specification needs considered as much as men’s. Consequently the Amira has been scrapped in this year’s range. Impressively, the Women’s Tarmac begins at a size 44cm, though.
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Of course one of the most significant updates is compatibility with wider tyres. Surprisingly the S-Works Tarmac will be specced with a 26mm Turbo Cotton tyre – measuring 29mm in profile when coupled with the equipped Roval wheels. The bike is capable of fitting up to 31mm tyres – opening up mild off-road terrains.
Typically, the S-Works edition has been coupled with Roval CLX 50 wheels along and Specialized saddle, stem and bars. The stem, interestingly, is an alloy composition. Specialized argue this presents a lighter and stiffer option than carbon.
That overall package comes in impressively light, with the S-Works Ultralight UL limited edition frame coming in at 5.9kgs using lighter eecycleworks brakes and a shallower section Roval wheelset.
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Price starts off at £3,500 with the Specialized Tarmac Expert. Below that the previoys generation SL5 will still be available throughout 2017 in a more affordable spec.
The previous generation SL5 frame offered diverse paint schemes and Specialized has unveiled a variety of special edition paint schemes.
The S-Works UL edition Tarmac is priced at £9,500 and the standard S-Works Tarmac at £9,000, with availability expected for July. See our next page for a full first ride review of the S-Works Tarmac.
First Ride Review: S-Works Tarmac SL6
The S-Works Tarmac has all the DNA of its predecessor but with a little extra punch and a little more smoothness
The previous S-Works Tarmac impressed several of the Cyclist team, being distinct in its all-round appeal and specifically its handling ability. On first impressions, this new edition has retained that appeal but honed a little of the top end performance, albeit with some concessions.
We rode the S-Works Tarmac in the hills of New Jersey, taking in middling climbs and some varied gravel-like terrain. I was impressed first and foremost by the specifiction of wider tyres, which carried none of the sluggishness or weight that can be a penalty of going wider.
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The 26mm Turbo Cotton tyres rolled well but capably absorbed the imperfections of the road. So too did it offer ample stability and control on a gravel track that I would not normally take on with an endurance racer of this calibre. This would be a tempting option for a classic cobbled sportive.
The Turbo Cotton tyres also add something substantial to aesthetic, sitting right on trend with the peloton’s proclivity for cotton wall tyres. Broadly, though, I found the dropped seat stays a little less fetching than the Tarmac SL5’s lines, but was open to becoming accustomed to them.
Spending three rides with the bike, it was the overall speed that was most discernible from the previous iteration.
Holding Speed
While aerodynamic gains are extremely difficult to accurately measure on the bike, there is undoubtedly a palpable increase in speed with the SL6 over the SL5 generation Tarmac.
Specifically, it holds speed in a way that I was well accustomed to with the original Specialized Venge. Up above 40kmh on a flat road, the Tarmac just sits comfortably without too much input of power to maintain that speed.
The SL5, by contrast, was spritely when changing speed but didn’t quite rumble along with the same sense of purpose on the flat.
Handling
In truth, despite Specialized’s claims I would be hard pressed to say the Tarmac SL6 handles better than the SL5. That’s largely owing to the quality of the SL5 when it came to sharp descending. It was a benchmark that I measured other frames by.
However, there’s no doubt that the S-Works Tarmac handles every bit as well as its predecessor, and I topped 80kmh on one of my initial test rides on a relatively technical descent. If I were pushing corners at the level of Sagan, I may have seen a gain with this frame over the previous Tarmac, but I suspect it exceeds my ability.
Comfort
Increased comfort is a big selling point with the new Tarmac, and there’s no doubting this is a comfortable endurance racer that will be well equipped for a long day in the saddle.
Some of that, however, has to be credited to the wider tyre spec. As any rubber enthusiast will know, 2mm on the tyres potentially changes more than the best carbon engineering.
The rear end with its new aero seatpost is certainly more robust than the Tarmac’s front end, and it’s easier to perceive pangs from the road on the saddle than on the bars. That’s a big bonus for handling, where the front end is rarely unsettled.
All-rounder
The Tarmac will most likely suit even the highest of demands of a specialist rider in any road discipline – whether it’s flat-section Strava junkies, sprinters or climbing aficionados. With its 733g frame weight, this is an airy ascender.
The rigidity of the frame is the other ingredient to capable climbing, and also pays dividends when it comes to high-end power transfer. I leapt on the pedals at 1,000 watts and felt no discernible flex.
With an endurance specialist like the Tarmac, there’s no doubt that a long time may be necessary to decide whether it’s an ideal long-term partner. Look out for an in-depth review in the coming months.
