In an impressive update to the Tour de France-winning Tarmac line, Specialized has moved away from the uncompromising rigidity of the previous version, the SL3. The new frame maintains the Tarmac line’s traditionally precise handling and drag-racer accelerations—courtesy of a rock-solid bottom bracket and rear end. But after listening to riders on the HTC-Highroad ProTeam, the engineers decided to soften the ride, just a touch. The result is a bike that’s as fast as any we’ve ridden, and lets you feel the road’s surface, but doesn’t overly punish you on rough pavement.
Much of the Tarmac’s compliance is the result of a redesigned head tube; it now has a smaller lower bearing (1 3/8, down from 1 1/2 inches) and a shape cribbed from the popular Roubaix line. The down and top tubes wrap around the head tube, giving it an hourglass shape, which Specialized says better soaks up vertical impacts. Despite this added compliance, the bike retains the SL3’s torsional stiffness.
The rock-solid power transmission that helped drive star sprinter Mark Cavendish to multiple wins proved just as impressive when the pavement turned upward. Aero road bikes might have the advantage in a headwind, but up steep hills, hammering over rough roads, and flying down descents, few bikes are better tuned than the SL4.
In fact, the new bike is better able to resist twisting forces, even as shaving weight was a primary goal. The new frame doesn’t surpass featherweight road racers like the Cannondale SuperSix EVO or Cervelo R5CA (video), but 875 grams for a 56cm frame still qualifies this bike as a climber’s dream machine.
The frame’s geometry was only slightly modified from the SL3: The wheelbase is a few millimeters shorter, depending on frame size, and, distinguishing itself from a trend toward taller head tubes on race bikes, the SL4’s head tube is shorter than the SL3’s, by as much as 20mm on the largest size.
As you’d expect at this price, there isn’t a single compromise on the spec—the S-Works FACT crank even spins on ceramic bearings, and the Shimano Di2 drivetrain shifted smoothly and reliably (a SRAM Red-equipped model drops the bill to $7,700). The Roval Rapide SL 45 aero wheels provided excellent all-around performance, complementing the bike’s overall character. I found the padding on the Body Geometry Romin Pro saddle a little thin for long and casual rides, but it’s probably suitable for more dedicated racers.
WEIGHT 14.88 lb. (58cm)
SIZES 49, 52, 54, 56, 58 (tested), 61cm
FRAME S-Works SL4 FACT 11r, FACT IS construction, carbon OSBB
FORK S-Works FACT carbon, full monocoque, OS race
COMPONENT HIGHLIGHTS Shimano Di2 electronic drivetrain, Dura-Ace cassette (11-25); Specialized S-Works FACT carbon crankset, Roval Rapide SL 45 wheels, S-Works Turbo tires, OS integrated bottom bracket w/ceramic bearings, Body Geometry Romin Pro saddle w/carbon rails
BUY IT IF Your Porsche has a roof rack
FORGET IT IF You prize the cushiest ride and a fat wallet
By Matt Allyn