A Climbing-Aero Bike? The Specialized S-Works Tarmac SL7
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After riding the latest generation S-Works Venge, we had nothing but praise. It had gone on a diet, losing more than a pound while becoming more aero in the process. At the same time it offered a much livelier experience in the hills and an all-around better ride quality. It felt like riding a Tarmac. Almost. It was about 90 percent of the way there to the benchmark-setting ride quality of its S-Works stablemate. But hold on a second, why are we talking about the Venge? After all, this is a review of the new Tarmac. Well, after riding the last Venge, we couldn’t help but wonder how much else Specialized could change before making one of its race bikes obsolete.
That day is finally here. Say goodbye to the Venge and hello to the S-Works Tarmac SL7, a single platform that is about as aero as the last S-Works Venge and butts right up to the UCI weight limit out of the box. Welcome to “the singularity.”
To make the next leap forward in race bikes, Specialized began the design process by making experimental frames. The first goal was to see what was the most bare-bones design possible. Those initial frames missed benchmarks for Venge-level stiffness, but were 20 percent under target weight. From there, composites were strategically added to hit stiffness targets. With the help of software, engineers went through hundreds of different layups and thousands of iterations testing minute changes in the carbon ply, like different angles and sizes. All said and done, Specialized settled on an S-Works frame made of FACT 12r material that weighs 800 grams…painted. Our size 54 sample tipped the scales at 6.8 kilograms (14.99 pounds)—with some room to drop if we cut the steerer tube and lost a couple spacers.
But low weight and Peter Sagan-approved stiffness were only two pieces of the puzzle. The brand that has been relentlessly telling us “aero is everything” had to stand by its principles. Specialized focused in on the parts of the bike most important to aerodynamics—the seat tube, seatstays, head tube and fork blades—and utilized its FreeFoil Shape Library, a catalog of aerodynamically optimized tube shapes developed with the help of software, to settle on the fastest design. Some aero elements like the Aerofly II handlebar were taken directly from the Venge. Add in internal cable routing and the deepsection Roval Rapide CLX wheels and you have a bike that is a claimed 45 seconds faster over 40 kilometers than the Tarmac SL6 (though a touch slower than the Venge).
While we’re at it, we should point out that this Tarmac is a bit heavier than the SL6. While many of us would love to have a bike for every occasion like a pro racer, Specialized has realized that that luxury is no luxury at all; it’s a sacrifice. That climbing bike won’t excel at the flat parts of a ride just as that aero bike becomes dead weight in the mountains. Over the course of a single stage, the best choice is almost always a bike that does both of those things very well—especially if you’re a pro limited to that 6.8kg UCI weight rule. And like anything S-Works, be prepared to open up the checkbook. Our Red eTap-equipped bike retails for $12,000.
The Tarmac SL7 shows up with dual personalities—in the best way possible. We’ve never quite experienced a package that can feel both like a climbing bike one moment and an aero bike the next, floating along at speed then accelerating out of the saddle up steep pitches. Reaching a climb after a long flat section, the SL7 can feel like having a soigneur waiting at the bottom with a new bike; the way its ride-feel adapts to each scenario is simply impressive.
We have to give credit where credit is due. The Roval Rapide CLX wheels, which weigh a meager 1,400 grams for their 51mm/60mm rim depths, are undoubtedly responsible for a not insignificant portion of the feeling of this bike. They provide the speed we know and love from aero wheels, while being light uphill and even making the trademark “whoosh, whoosh” sound of unbridled speed while you climb out of the saddle. They perfectly complement the Tarmac’s newfound zeal for being the best at everything.
Sprinting on the new Tarmac is akin to a supercomputer crunching numbers; there’s absolutely zero latency—just think it and the bike will do it. But the stiffness and aero tubing does seem to have come at a slight reduction in comfort. The Tarmac now feels slightly more rigid, with more road buzz reaching the saddle. But it’s certainly no deal breaker for this otherwise impeccable ride, especially when you can add extra comfort through high-volume tires up to 32c.
The SL7 represents what Specialized can do at the edge of the UCI weight limit, balancing aero and low weight for the fastest overall bike. Now we’re left wondering, if that limit disappeared, what would Specialized’s ultimate race bike look like?
$12,000 (as built); 14.99 lbs/6.8kg (size 54 w/o pedals or cages)
SRAM Red eTap AXS (48/35 chainrings; 10–33 cassette); S-Works Aerofly II handlebar; Specialized Tarmac stem; Specialized Tarmac seat post; S-Works Power saddle; Roval Rapide CLX wheels; 26c S-Works Turbo Cotton tires.