Specialized’s Tarmac SL9 S-Level is built to wreck your Zone 2 ride

I love a good Zone 2 ride. There’s nothing like getting on the bike, settling into a groove, and letting the miles (and hours) flow by. But sometimes when I hopped on the Specialized Tarmac SL9 S-Level, Zone 2 would turn into a tempo ride. It was like having a little imp—the stereotype dressed in red with the pitchfork—on my left shoulder whispering into my ear: “Go fast. This bike was built to go fast. Speed is good. You can do a Zone 2 ride tomorrow.” Normally, I’d count on the good imp—the dude with the harp and wings—on my right shoulder to restrain these urges. But the Tarmac is so seductive that he would just shrug and say “he’s got a point.” And in a moment of weakness, I would drop the hammer and head into the red, just because the SL9 makes that so rewarding.

The Tarmac SL9 is Specialized’s aero road bike, with the S-Level sitting just below the S-Works in Specialized’s top tier of carbon, aero road bikes, where it replaced the Tarmac SL8 Pro. After it got an update this year, I spent several weeks riding it, putting nearly 1,000 miles on it

Specialized offers the Tarmac SL9 in four models, all available with SRAM and Shimano drivetrains (Ars tested the SRAM version). Notably, you don’t need to buy the top-of-the-line bike to get the top-of-the-line groupset. Here’s the breakdown of the Tarmac SL9 lineup (note that the Shimano versions of the Expert is 20 g lighter and Comp is 70 grams heavier than the SRAM versions):

The $10,500 S-Level offers the top-of-the-line SRAM Red groupset and integrated cockpit, just like the $14,000 S-Works. But the frameset, wheelset, and saddle differ. The major difference is the frame: the S-Level gets the same carbon-fiber FACT 10r frame as the Expert and Comp. At 822 g for a 56 cm frame, the FACT 10r is 135 g heavier than the FACT 12r used on the S-Works. Despite the weight difference, Specialized says the FACT 10r offers the same stiffness and comfort characteristics as its lighter sibling. Along with the frame, different wheelsets and saddles make the S-Level 500 g heavier than the S-Works. With bottle cages, a Garmin mount, and my preferred Shimano XTR XC PD-M9200 MTB pedals, the S-Level I tested weighed in at 7.98 kg. By way of comparison, my own road bike—a Gen 8 Trek Madone—weighs in at 7.71 kg.

I rode the S-Level all around the Chicago suburbs as well as in central Illinois. Unlike the Diverge 4 Pro, I wasn’t able to test its climbing ability in the Rocky Mountains. All we’ve got in most of Illinois are short, punchy climbs … and a lot of long flats. I rode The S-Level on everything from freshly laid asphalt to freshly laid chipseal, including a couple of 60-mile-plus rides on the country roads downstate.

Visually, the S-Level is striking. The blue-on-white with gray striping is one of Specialized’s better-looking colorways. And it looks aerodynamic. Indeed, Specialized says the Tarmac SL9 is the most aerodynamic road bike it has ever made. Notable changes from the previous-generation Tarmac SL8 to SL9 involved tweaking the head tube, rerouting the rear hydraulic brake hose to accommodate the narrower head tube, and moving to a dropped-down tube for improved aerodynamics. But the most visually striking change is the Win Fin. As the seat tube rises from the bottom bracket, it deviates from the vertical to follow the curve of the wheel as it approaches the seat stays. When riding with just a single water bottle on the downtube—common in pro races where a full bottle is just a team car away—Specialized claims Win Fin saves riders half a watt.

The S-Level I tested came with Specialized’s 30 mm Specialized Cotton TLR tires—used by Red Bull-BORA-hansgrohe on the UCI World Tour—in a tubeless setup. According to Bicycle Rolling Resistance, the Cotton TLR outperforms the much-loved Continental GP 5000 S TR tires when it comes to rolling resistance (at 28 mm). Using Silca’s tire pressure calculator, I rode with the tires inflated to 73 psi in the front and 75 psi in the rear, a departure from the 62/64 setting on my 32 mm Contis—and there is a slight, but noticeable difference in ride comfort between the S-Level and my own road bike. Mounted on the Roval Rapide CL III carbon wheels with 21 mm internal width, the Cotton TLR tires measured 30.2 mm wide (my 32 mm Contis are a hair over 33 mm).

Out on the road

On every surface shy of brand-new chipseal, the Tarmac felt comfortable and balanced, with the bike absorbing some of the punishment meted out by uneven pavement. Fresh chipseal is another matter entirely, as it feels more like gravel, which felt jarring on the SL9 S-Level. What was particularly impressive about the SL9 is how great it feels on long rides. Some manufacturers are skilled at building aero bikes that feel great on hours-long rides, and the Tarmac is just as good as the Trek Madone SLR 9 AXS Gen 8 I reviewed in this regard.

When you’re ready to drop the hammer, the S-Level is your willing accomplice. It’s twitchy in all of the good ways, with instantaneous response to the rider’s effort. The SRAM Red AXS groupset makes shifting buttery smooth (and the bonus buttons on the brake hoods allow the rider to change screens on the bike computer without releasing the brake hoods), and the drivetrain (50t/37t chainrings and a 10t-36t cassette) offers gear ratios for every type of terrain.

The first few seconds of a climb on the Tarmac SL9 S-Level feel like they come for free. Whether I stayed seated or cranked out watts in an upright position, there was no lag or flex as the bike snapped forward. Descents were amazing, and cornering on the S-Level is sublime—I felt balanced and in control at all times.

There are a few nits to pick. The reach to the brakes in the drops felt excessive on my first couple of rides, and I had to adjust them slightly to brake easily on descents. Also, I would prefer shorter cranks on the Tarmac. The trend among professional riders has been toward shorter cranks because it makes holding an aero position easier and reduces hip and knee flexion. To its credit, Specialized reduced the crank length from 172.5 mm on the 56 cm SL8 to 170 mm on the same-sized SL9, but I run 165 mm cranks on my road bikes and noticed the difference on the S-Level. One demographic that buys expensive road bikes is middle-aged dudes with empty nests and disposable incomes, and they are the ones most likely to appreciate shorter cranks.

The 3D-printed Power Pro Mirror is a fine saddle, but there’s a reason I ride with a Specialized S-Works Power with Mirror on my Trek—it’s more comfortable and offers noticeably more padding around the cutout. And if I owned the S-Level, I’d move to 32 mm tires as soon as I wore out the 30s for better compliance.

Specialized brags that the Tarmac SL9 S-Works is the fastest bike ever made, and it claims the S-Level is the second-fastest bike ever made. I can’t speak to that claim, but the SL9 S-Level checks all of the boxes for an aerodynamic road bike. It’s lightweight, it’s fast, it’s responsive, and it’s great on rollers and punchy climbs. And it’s nice to get a SRAM Red groupset without springing for the absolute top-of-the-line model. $10,500 is a hefty sum for a road bike, but I’d be a lot more willing to forego the weight savings from the lighter components (frame, wheels, seatpost, bottom bracket, and bearings) of the S-Works—and spend $3,500 less. The real selling point, though, is how often it made me want to go harder just for the fun of it. That little imp has a point: Zone 2 can wait until tomorrow.