The Takeaway: A handful of refinements and updates help the Tarmac maintain its position as the benchmark UCI-legal road-race bike.
More aerodynamic: 45 seconds faster than the Tarmac SL6 over 40km
So fast, it kills of the Venge aero-road bike.
S-Works frame is more aerodynamic without any weight gain compared to SL6: still about 800 grams
Now uses a threaded BB for easier service, with no trade-off in stiffness or weight.
Price: $7,000 (Tarmac SL7 Pro Ultegra Di2)
Weight: 16.19 lb. (54cm)
With the launch of the new Tarmac, Specialized brings its road-race bikes full circle. When Specialized got into pro racing, there was one kind of road race bike and it was as stiff and light as possible. Then the aero-road trend started and it presented riders with a choice: a stiff and light—but not at all aero—bike, or a heavier, less-stiff, aero road bike.
Over time, the two categories began to converge: The stiff and light bikes got more aero, and the aero bikes got stiffer and lighter. Still, racers had to choose between a lighter, less-aero bike, and a heavier, more aero bike. Each bike was advantageous in different situations. The problem for racers: If both bikes are advantageous at different times in the same race, which bike do you pick? That’s not a choice a racer, especially a top-level pro, wants to make. They want one bike that is fast everywhere.
That’s the goal of the new Specialized Tarmac SL7, which replaces the superb Tarmac SL6 as the company’s premier race bike—a no-compromise race bike that’s as fast as an aero bike and as light as a climbing bike. And Specialized is so confident it achieved that goal that it’s killing off the Venge (it remains as a frameset-only option in some markets), and Specialized’s pro teams will exclusively race the Tarmac.
The New New
The big change for the new-generation Tarmac: It’s more aerodynamic. Specialized claims it is 45 seconds faster over 40k (25 miles) compared to the Tarmac SL6. Aerodynamically, that puts the SL7 close to Specialized’s Venge. The Venge is still a touch more slippery: On a flat 40k time trial, it’s 9 seconds faster.
However, all things equal, the new Tarmac is 350 grams lighter. Which means that the Tarmac accelerates more quickly, and is faster up hills. The tipping point when the Tarmac’s lower weight overcomes the Venge’s aero advantage happens on a 3 to 5 percent grade, depending on the rider's effort.
The SL7’s aero gains over the SL6 come with no weight gain. The S-Works SL7 12r carbon frame weighs the same as the S-Works SL6 disc frame: about 800 grams, painted (for a 56cm). Specialized claims the complete S-Works Shimano Dura-Ace Di2 model, with power meter and clincher wheelset, comes out of the box at 6.7 kilograms. The S-Works with SRAM Red AXS weighs about 180 grams more than the Dura-Ace Di2 model (sorry SRAM fans).
Tarmac SL7 Pro and Expert models—my review bike is a $7,000 Tarmac Pro Shimano Ultegra Di2—use a 10r carbon frame that’s about 120 grams heavier than the S-Works frame. However, the heavier frame’s aerodynamic, stiffness, and compliance properties are the same, says Specialized.
The SL7’s most surprising aero detail is what it doesn’t have: an airfoil down tube. The SL7’s down tube is round with little obvious aero shaping. Usually the down tube gets the MOST aero shaping. However, Cameron Piper, the Tarmac’s product manager, says that the down tube “is not a significant contributor to aero performance, even using weight yaw averages that account for crosswinds. The marginal gain that could have been made from a deeper down tube in high yaw scenarios would have added a considerable amount of weight.” According to Specialized, the tubes that “truly impact aero” are the seat tube, seatstays, head tube, and fork blades.
Like the SL6, the SL7 gets dropped seat stays, though the SL7’s are more angular and almost look like they were pulled directly from the Venge. Though some companies feel differently, Piper says Specialized’s testing indicates dropped stays provide an aerodynamic advantage, adding, “Weight gain, if any, is marginal, and improvement in rear end stiffness from a compact rear triangle is there. Construction wise, it’s not easy, but the benefits outweigh the difficulty.”
However, a good chunk of the SL7’s overall aero advantage over the SL6 doesn’t come from changes to the frame’s tube shapes. The Aerofly bar and Rapide wheelset account for 15 to 20 seconds alone. So, you could add those parts to your SL6 and halve the SL7’s aero advantage. The hidden hoses, housing, and wires are another reason the SL7 is more slippery than the SL6.
Details and Features
The new SL7 gets a threaded bottom bracket. Though threaded BBs make routine service easier, I usually hear that wide, press-fit bottom brackets allow a brand to make a lighter and stiffer frame. But Piper claims Specialized uses a construction method that allows the use of a threaded BB that results in a lighter overall frame and no stiffness penalty. Power meter users will be happy to note that there is plenty of clearance for all sorts of power meters, including left-side pods.
The SL7’s seat tube cuts a deeper and more aero profile than the SL6’s, which results in a new (deeper and more aero looking) seatpost. It comes in 20mm and zero offset and—like the Venge’s post—the Di2 junction box resides just under the saddle clamp. A hidden seat binder resides in the top tube.
Hoses, housing, and wires are completely hidden. They run through the bar, so they need to be pulled for a handlebar change. But you may swap stems without pulling anything. The SL7’s stem is based on the Venge’s, but it’s 45 grams lighter without losing any stiffness. A computer and accessory mount that integrates into the stem’s faceplate is included.
The SL7 is compatible with mechanical and electronic drivetrains. Even though the stock front end is highly integrated, the SL7 is compatible with any handlebar and stem.
Lastly, Specialized bumped tire clearance up slightly so the SL7 can fit tires up to 32mm.
Fit and Geometry
There's nothing radical going on with the SL7’s frame fit or handling geometry. In fact, they’re both the same as the Venge and Tarmac SL6. It is a race bike fit: long and low. There are seven sizes, from 44cm to 61cm.
Naturally, Specialized’s “Rider First Engineering” is present in the SL7, which aims to let every rider experience the same handling regardless of frame size. Piper says the SL7’s handling targets were the same as those of the SL6, though the SL7 has refinements that cut weight from most frame sizes without changing how the bike handles. According to Piper, the 56cm—the size used to measure for the brands weight claims—“is within 5 grams of its predecessor; every other size saw a more substantial weight savings over the SL6.”
The SL7 Line
My review bike is the $7,000 Pro Ultegra Di2. It has the Aerofly bar and Roval Rapide rims, so, aerodynamically, it’s identical to the S-Works model. However, the frame and parts are heavier; it’s not as fast as the S-Works model is on a climb. But it’s also $4,000 less.
Shimano Ultegra Di2: perfect. Shimano’s Di2 offers the best shifting on the market. The brakes are smooth at the lever with a firm bite and predictable power.
Wheels are Roval’s Rapide CL with DT-Swiss 350 hubs and j-bend spokes. The rims are 51mm/60mm (front/rear) deep, and the front rim is wider and more blunt than the rear, which helps cross-wind stability. They are NOT a tubeless-ready wheelset, which is a bit of a bummer.
The tires are Specialized S-Works Turbo in 26. These are a good all-round tire, and pretty durable as well.
Bar, stem, post, and saddle are all from Specialized. The stock saddle is a Power with titanium rails. Specialized sent my bike with the new Mirror saddle. It‘s really impressive: awesome pressure distribution and it’s like your butt is cradled by a springy little hammock.
SL7 VS. SL6
One important note before I dive into my ride impressions: The SL7 is legitimately better than the SL6; however, the SL7 feels a lot like that SL6. Not exactly, but very close. That’s intentional, as Specialized knows the SL6 is a great riding and handling bike.
But if you’re already on an SL6, I can‘t think of a super-compelling reason for you to swap it for an SL7 unless you really, really, want a small aero bump (as I noted above, you could add the Aerofly bar and Rapide wheels to an SL6 and cut the SL7’s aero advantage in half).
If you love a deal, now is probably a great time to snap up a new SL6 on closeout, or pick up a used SL6 from The Pro’s Closet.
The thing to remember about the Tarmac is that it’s subject to the UCI’s regulations because it is built for Specialized’s professional race teams. So, when you hear the company pitch it as a “no-compromise” bike and call it “the fastest race bike,” what it means is it’s the fastest all-around UCI LEGAL road bike it can currently make.
And I am a bit frustrated with the UCI race bike thing because I think they force brands into a box that encourages them to build really similar bikes. That said, it is fascinating to see what everyone can do when restricted by the same rules. And among the bikes that adhere to the UCI’s rules, I think the Tarmac is the benchmark, slightly eclipsing the excellent new Trek Émonda. That’s because the SL7 is not just a fast bike, it’s fast and nearly perfectly balanced.
Speed is freakishly easy to come by on this bike, and it seems to make going faster easier than any other bike I’ve ridden. Power transfer is superb, with electric-like efficiency and an explosive feel when you increase power to the pedals. It doesn’t matter if you ramp up the pace just slightly on a climb, or suddenly jump on the pedals to sprint with everything you have, the SL7 responds immediately with unfiltered forward motion. The aero claims seem to measure up: It punches through the low 20s into the mid to higher 20s with ease.
Given this hyper-efficient feel and easy speed, its smoothness is otherworldly. On the stock tires, and on those deep wheels, it practically glides in a way that belies its purpose as a tool for pro racing. The pavement around me is largely crap–and I do not shy away from dirt roads—and I found the SL7’s smoothness surprising, refreshing, and absolutely delightful. On most race bikes I review, I’m chucking the stock tires as soon as I can and stuffing in the largest rubber I can fit in an effort to save my sanity. I didn’t need to do that on the SL7.
Even better, it was smooth and comfortable but not overdamped and lifeless, which is—based on how few bikes feel this way—a really tricky balance to achieve. I will say, however, I didn’t find the tops of the Aerofly bar comfortable to hold onto in any situation, especially when the road was bumpy—though they seem to be reasonably compliant when holding onto the hoods or drops.
Then there’s how it corners, which is practically erotic. This bike loves to corner and I love to corner on it because of how much it loves to corner. Which is good because it is so good at going fast and so smooth that (until I got used to it) I was often surprised at how fast I was entering corners. It tips in with a light touch, drops in predictably, and sets into its arc almost automatically—but that’s the way most good race bikes feel these days. The SL7 does something else I haven’t felt in a carbon race bike: There’s a slight bit of give that lets the bike bend and flex in a way that lets it corner faster, with better grip, and greater compliance. It reminds me of the way it feels when my snowboard flexes and carves when rolled onto its edge. Until now, I’ve felt this only in metal bikes—usually steel—but the SL7 has this feel without any trade-off in other areas of its stiffness.
Again, I want to stress that all these impressions are based on evaluating the Tarmac exclusively through the lens of a pavement-centric, UCI-legal, race bike. But 99 percent of us aren’t subject to the UCI’s equipment regulations. Wouldn’t it be great if a brand like Specialized took all the tools and knowledge it uses to build its premier UCI race bikes and used them to build the best bike it could with no regard for the UCI’s rules? Boy, that would be something, wouldn’t it? (That may or may not be a hint.)
But if you want the best, UCI-legal bike for getting from point A to point B as fast as possible on pavement—up, down, flat, or otherwise—I believe that bike is the Tarmac SL7.
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